Nuitka Release 2.1 (Draft)

Bug Fixes

  • Windows: Using older MSVC before 14.3 was not working anymore. Fixed in 2.0.1 already.

  • Compatibility: The dill-compat plugin didn’t work for functions with closure variables taken. Fixed in 2.0.1 already.

    def get_local_closure(b):
      def _local_multiply(x, y):
        return x * y + b
      return _local_multiply
    fn = get_local_closure(1)
    fn2 = dill.loads(dill.dumps(fn))
    print(fn2(2, 3))
  • Windows: Fix, sometimes kernel32.dll is actually reported as a dependency, remove assertion against that. Fixed in 2.0.1 already.

  • UI: The help output for --output-filename was not formatted properly. Fixed in 2.0.1 already.

New Features

  • Plugins: Added support for constants in Nuitka package configurations. We can now using when clauses, define variable values to be defined, e.g. to specify the DLL suffix, or the DLL path, based on platform dependent properties.

  • Plugins: Make relative_path, suffix, prefix in DLL Nuitka package configurations allowed to be an expression rather than just a constant value.


  • Scalability: The code trying avoid merge traces of merge traces, and to instead flatten merge traces was only handling part of these correctly, and correcting it reduced optimization time for some functions from infinite to instant. Less memory usage should also come out of this, even where this was not affecting compile time as much. Added in 2.0.1 already.


  • Quality: Added auto-format of PNG and JPEG images. This aims at making it simpler to add images to our repositories, esp. Nuitka Website. This now makes optipng and jpegoptim calls as necessary. Previously this was manual steps for the website to be applied.

  • Release: Remove month from manpage generation, that’s only noise in diffs.


This release is not done yet.

Nuitka Release 2.0

This release had focus on new features and new optimization. There is a really large amount of compatibility with things newly added, but also massive amounts of new features, and esp. for macOS and Windows, lot of platform specified new abilities and corrections.

Bug Fixes

  • Fix, workaround for private functions as Qt slots not having names mangled. Fixed in 1.9.1 already.

  • Fix, when using Nuitka with pdm it was not detected as using pip packages. Fixed in 1.9.1 already.

  • Fix, for pydantic our lazy loader parser didn’t handle all cases properly yet. Fixed in 1.9.1 already.

  • Standalone: Added data files for pyocd package. Fixed in 1.9.1 already.

  • Standalone: Added DLL for cmsis_pack_manager package. Fixed in 1.9.1 already.

  • Standalone: Fix, the specs expanded at run time in some causes could contain random characters. Fixed in 1.9.2 already.

  • Fix, {"a":b, ...}.get("b") could crash at runtime. Fixed in 1.9.2 already.

  • Standalone: Added data files for pyproj package. Fixed in 1.9.2 already.

  • Standalone: Added more metadata requirements for transformers package. Fixed in 1.9.2 already.

  • Plugins: Fix, could crash when including packages from the command line, if they had yaml configuration that requires checking the using module, e.g. anti-bloat work. Fixed in 1.9.3 already.

  • Standalone: Added support for delphifmx package. Fixed in 1.9.4 already.

  • Android: Fix, cannot exclude libz on that platform, it’s not a full Linux OS. Fixed in 1.9.3 already.

  • Standalone: Add needed DLLs for bitsandbytes package. Fixed in 1.9.3 already.

  • Windows: Fix, newer joblib was not working anymore. Fixed in 1.9.3 already.

  • Windows: Fix, could crash when working with junctions that switch drives. Fixed in 1.9.3 already.

  • Fix, was crashing with poetry installed environments. Fixed in 1.9.3 already.

  • Standalone: Added support for newer chromadb package. Fixed in 1.9.3 already.

  • Fix, could crash in report creation on modules excluded that were asked via command line for inclusion. Fixed in 1.9.3 already.

  • Anti-Bloat: Fix for newer streamlit, it was causing SyntaxError for the compilation. Fixed in 1.9.4 already.

  • Arch: Added support for their OS release file location too. Fixed in 1.9.4 already.

  • Windows: Fix, MinGW64 doesn’t accept chinese module names a C source files. Use short paths for these instead. Fixed in 1.9.4 already.

  • Standalone: Added missing DLL for libusb_package package. Fixed in 1.9.4 already.

  • Fix, properly skip directories with non-module top level names when trying to find top level packages of distributions. Fixed in 1.9.4 already.

  • Fix, avoid memory leak bug in triggered by rich package. Fixed in 1.9.4 already.

  • Python3.11+: Fix, didn’t detect non-keywords on star dict calls in some cases. Fixed in 1.9.4 already.

  • Fix, avoid crashes due to unrecognized installers on macOS and Windows, some packages that are built via legacy fallbacks of certain pip versions do not leave any indication of their origin at all. Fixed in 1.9.4 already.

  • Windows: Fix, need to indicate that the program is long path aware or else it cannot work with the paths. Fixed in 1.9.4 already.

  • Debian: The extern namespace might not exist in the pkg_resources module, make the code work with versions that remove it and use the proper external package names then. Fixed in 1.9.6 already.

  • Compatibility: Fix, need to also have .exists method in our files reader objects. Fixed in 1.9.5 already.

  • macOS: Fix, PyQt5 standalone can fail due to libqpdf too.

  • Compatibility: Make dill-compat plugin support module mode too, previously this only worked for executables only. Fixed in 1.9.6 already.

  • Standalone: Added data file for curl_cffi package. Fixed in 1.9.6 already.

  • Windows: Fix warnings given by MinGW64 in debug mode for onefile compilation. Fixed in 1.9.6 already.

  • Python2: The handling of DLL permission changes was not robust against using unicode filenames. Fixed in 1.9.7 already.

  • Python2: Fix, could crash on Debian packages when detecting their installer. Fixed in 1.9.7 already.

  • Standalone: Added required data file for astor package. Fixed in 1.9.7 already.

  • Reports: Fix, in case of build crashes during optimization, the bug report creation could be crashing because the module is not in the list of done modules yet. Fixed in 1.9.7 already.

  • Python2: Fix, unittest.mock was not yet available, code attempting to use it was crashing the compilation. Fixed in 1.9.7 already.

  • Accelerated: Fix, tensorflow configuration removing site usage needs to apply only to standalone mode. Fixed in 1.9.7 already.

  • Plugins: Fix, the get_dist_name Nuitka package configuration function could crash in some rare configurations. Fixed in 1.9.7 already.

  • Standalone: Added necessary data file for pygame package. Added in 1.9.7 already.

  • Standalone: Fix, was not properly handling standard library overloading module names for decisions. Inclusion and compilation mode were made as if the module was part of the standard library, rather than user code. This is now properly checking if it’s also an actual standard library module.

  • Plugins: Fix, crashing on missing absence message with no UPX binary was found.

  • Windows: Fix, couldn’t load extension modules from UNC paths, so standalone distributions failed to launch from network drives. This now works again and was a regression from adding support for symlinks on Windows.

  • Standalone: Added support for non-legacy pillow in imageio package.

  • Standalone: Added required easyOCR data file.

  • Nuitka-Python: Fix, do not demote to non-LTO for “too many” modules there in the default auto mode, it doesn’t work without it.

  • Fix, python install could fail. Apparently it tries to lookup Nuitka during installation, which then could fail, due to hacks we due to make sure wheels are platform dependent. That hack is of course not really needed for install, since no collision is going to happen there.

  • macOS: Fix, the standard matplotlib plugin that uses native UI was not included yet, and it was also not working due to bindings requiring uncompiled functions, which is now worked around.

  • Compatibility: Add back PySide6 workaround for overloading names like update with slots.

  • Standalone: Added geopandas data files.

  • Python2: Fix, code objects must be made from str exactly, unicode however was used in some configurations after recent improvements to the run time path handling.

  • Standalone: Added missing data files for boto, the predecessor of boto3 as well.

  • Standalone: Added missing DLL for tensorflow factorization module.

  • Compatibility: Fix, PySide2 and PySide6 signal disconnection without arguments were not working yet.

  • Standalone: Added support for toga.

  • Scons: Fix, need to Avoid picking up clang from PATH on Windows with --clang provided, as only our winlibs version is really working.

  • Fix, version of setuptools when included (which we try to avoid very much) was None which breaks some users of it, now it’s the correct version so checks of e.g. setuptools_scm can succeed.

  • Fix, icon options for platforms were conflated, so what should be windows only icon could get used on other platforms as well.

  • Fix, could not create compiled methods from compiled methods. Also now errors out for invalid types given properly.

New Features

  • Plugins: Added support for module decisions, these are parameters provided by the user which can be used to influence the Nuitka per package configuration with a new get_parameter function. We are using these to control important choices in the user, sometimes warning it to make that decision, if the default can be considered problematic.

  • Plugins: Added support for variables in Nuitka package configurations. We can now query at compile time, values from installed packages and use them, e.g. to know what backend is to be used.

  • Standalone: Added module decision to disable Torch JIT. This is generally the right idea, but the decision is still asked for since some packages and programs want to do Torch Tracing, and that is then disabled as well. This makes a bunch of transformers programs work.

  • Standalone: Added module decision to disable Numba JIT. This makes numba work in some cases, but not all. Some packages go very deep with JIT integration, but simpler uses will now compile.

  • New option --include-onefile-external-data allows you to specify file patterns that you included by other data files others, but to put those files not inside, but on the outside of the onefile binary. This makes it easier to create deployments fully within Nuitka project configuration, and to change your mind back and forth without adding/removing the data file option.

  • macOS: Added new value auto for detecting signing identity, if only one is available in the system.

  • macOS: Added support for --copyright and --trademark information to be in app bundles as well, this was previously Windows only.

  • Windows: Added support for using junctions in the Python environment, these are used e.g. when installing via scoop. Added in 1.9.2 already.

  • Added option --cf-protection to select the control flow protection mode for the GCC compiler and deviate from default values of some environments to less strict values.

  • Reports: Added output filename to report, mainly intended for automatically locating the compilation result independent of options used.

  • Plugins: Now provides a checksum for yaml files, but not yet verifies them at runtime, to ask the user to run the checker tool to update it when they make modifications.

  • Windows: Detect when we create too large compiled executables. There is a limit of 2GB that you might e.g. violate by attempting to embed very large files. This doesn’t cover onefile yet.

  • Watch: The tool can now create PRs with the changes in Nuitka-Watch for merging, this is for using it in the CI.

  • Watch: Scanning for Python versions now requires pipenv to be installed in them to be found.

  • Watch: Added ability to create branch and PR from watch run results.

  • Plugins: Added overridden-environment-variables feature to package configuration. These are environment variable changes that only last during the import of that module and are undone later.

  • Plugins: Added force-environment-variables feature to package configuration. These are environment variable changes done on module import that are not undone.

  • Nuitka-Action: Nuitka options that can be given multiple times, cannot be specified multiple times in your workflow. As a workaround, Nuitka now allows in Actions, to use new lines as separator. This is best done with this kind of quoting a multiline string.

    include-data-dir: |
  • The Nuitka package configuration no-auto-follow now applies recursively, i.e. that a top level package can have it, and not every sub-package that uses a package but should not be automatically followed, does have to say this. With this e.g. networkx configuration became simpler, and yet covered automatically older versions as well, and future changes too.

  • Windows: Added support for compiling in case sensitive folders. When this option is enabled, using os.path.normcase can make filenames not found, so with a few cleanups, for lazy code that wasn’t really using the APIs designed for comparisons and filename suffix testing, this works now better.

  • The __compiled__ value has a new attribute containing_dir that allows to find where a module, accelerate executable, a standalone dist folder, a macOS app bundle, or the onefile binary lives in a consistent fashion. This allows esp. better use than sys.argv[0] which points deep into the .app bundle, and can be used cross platform.


  • Scalability: Avoid variables that are not shared to be treated as if they were, marking their type shape as tshape_unknown in the first micro pass. These micro passes are not visible, but basically constitute a full visit of the module tree over and over, until no more optimization is changing it. This can lead to quicker resolution, as that unknown type shape effectively disallowed all optimization for variables and reduce the number of necessary micro passes by one.

  • Escaped variables did provide a type shape tshape_unknown and while a lot of optimization looks for value knowledge, and gets by the escaped nature of the value, sometimes, this was seriously inhibiting some of the type based optimization.

  • Loop type shape analysis now succeeds in detecting the types for this code example, which is sort of a break-through for future performance enhancements in generated code.

    # Initial the value of "i" is "NUITKA_NINT_UNASSIGNED" in its
    # indicator part. The C compiler will remove that assignment
    # as it's only checked in the assignment coming up.
    i = 0
    # Assignment from a constant, produces a value where both the C
    # and the object value are value. This is indicated by a value
    # of "NUITKA_NINT_BOTH_VALID". The code generation will assign
    # both the object member from a prepared value, and the clong
    # member to 0.
    # For the conditional check, "NUITKA_NINT_CLONG_VALID" will
    # always be set, and therefore function will resort to comparing
    # that clong member against 9 simply, that will always be very
    # fast. Depending on how well the C compiler can tell if an overflow
    # can even occur, such that an object might get created, it can even
    # optimize that statically. In this case it probably could, but we
    # do not rely on that to be fast.
       # Here, we might change the type of the object. In Python2,
       # this can change from ``int`` to ``long``, and our type
       # analysis tells us that. We can consider another thing,
       # not "NINT", but "NINTLONG" or so, to special case that
       # code. We ignore Python2 here, but multiple possible types
       # will be an issue, e.g. list or tuple, float or complex.
       # So this calls a function, that returns a value of type
       # "NINT" (actually it will become an in-place operation
       # but lets ignore that too).
       # That function is "BINARY_OPERATION_ADD_NINT_NINT_CLONG"(i, 1)
       # and it is going to check if the CLONG is valid, add the one,
       # and set to result to a new int. It will reset the
       # "NUITKA_NINT_OBJECT_VALID" flag, since the object will not be
       # bothered to create.
       i = i + 1
    # Since "NUITKA_INT_OBJECT_VALID" not given, need to create the
    # PyObject and return it.
    return i
  • Python3.11+: Use tomllib from standard library for our distutils integration into pyproject based builds.

  • Avoid late specialization for None returns in generators and do it during tree building already, to remove noise.

  • Added successful detection of static libpython for self compiled Python Linux and macOS. This makes it work with pyenv as well.

  • Standalone: Avoid including .pyx files when scanning for data files, these are code files too, in this case source files that are definitely unused most of the time.

  • macOS: Make static libpython default with CPython for more compact standalone distribution and faster binaries.

  • Remove non-existent entries from sys.path, avoiding many file system lookups during import scans.

  • Anti-Bloat: Avoid using triton in torch package in more cases. Added in 1.9.2 already.

  • Anti-Bloat: Avoid using pytest in knetworkx package in more cases. Added in 1.9.2 already.

  • Anti-Bloat: Avoid using IPython in distributed package. Added in 1.9.3 already.

  • Anti-Bloat: Avoid using dask in skimage. Added in 1.9.3 already.

  • Anti-Bloat: Avoid using triton in the bitsandbytes package. Added in 1.9.3 already.

  • Anti-Bloat: Avoid IPython in tf_keras package as well. Added in 1.9.6 already.

  • Anti-Bloat: Avoid unittest in mock.mock module. Added in 1.9.7 already.

  • Avoid importing setuptools_scm during compilation when using the tqdm inline copy, this also avoids a warning on Ubuntu. Added in 1.9.7 already.

  • Anti-Bloat: Avoid doctest in skimage in their tifffile inline copy as well. Added in 1.9.7 already.

  • Anti-Bloat: Avoid h5py.tests with older h5py as well. Added in 1.9.7 already.

  • Anti-Bloat: Using distributed.utils_test is also considered using pytest.

  • Anti-Bloat: Avoid IPython in the pip package.

  • Anti-Bloat: Avoid site module for older tensorflow versions too.

  • Anti-Bloat: Avoid more unittest usages in tensorflow packages.

  • Anti-Bloat: Avoid nose in skimage package.

  • Anti-Bloat: Avoid nose in networkx package.

  • Anti-Bloat: Avoid nose in pywt package.


  • UI: Change template paths over from %VAR% to {VAR}.

    The old spec values are migrated transparently and continue to work, but get a warning when used.

    The new code detects unknown variable names and more formatting issues than before.

    Using only the {PID} value for process ID, is now making it temporary value for onefile, that was previously a bug.

    The main benefit and reason of doing this, is that Windows CMD.EXE does expand those values before Nuitka sees them as even with quoting %TEMP% is the current one on the building machine, a recipe for disaster. As some people still use that, and e.g. os.system or subprocess with shell=True will use it too, this is just not sustainable for a good user experience.

    As a result, compile time and run time variables now clash, there is e.g. {VERSION} (program version information given) and {Version} (Nuitka version), and we should clean that up too.

  • Project: Added Code of Conduct. Adapted from the one used in the Linux kernel.

  • UI: Warnings given by Nuitka used to be in red color, changed those to be yellow for consistency.

  • User Manual: Added pointer for Nuitka-Action Nuitka-Action for users interested in using Nuitka in GitHub workflows.

  • Added .gitignore to build folder that just causes these folders to be ignored by git.

  • User Manual: Added information on how to debug fork bombs from created binaries.

  • Debugging: The output of --experimental=--report-refcounts that we use to show leaks of compiled time objects at program exit, now counts and reports on functions, generator objects and compiled cells as well.

  • Quality: Warnings from yamllint not disabled are errors. These were only output, but didn’t cause the autoformat to error exit yet.

  • UI: Enhanced formatting of info traces, drop the :INFO part that shouts, and reserve that for errors and warnings. Also format info messages to make sure they fit into the line.

  • UI: Changed --show-source-changes to accept module pattern to make it easier to only see the ones currently being worked on. To get the old behavior of showing everything, use * as a pattern.

  • UI: Allow using ~ in data files source path for command line options and expand it properly.

  • Quality: Enhanced schema for our package configuration yaml files to detect suffixes with leading dots, that is not wanted. These now fail checks, but we also tolerate them now.

  • Quality: Check module names used in the package configuration yaml files for validity, this catches e.g. trailing dots.

  • Quality: Make sure to really prefer clang-format from Visual Code and MSVC for formatting C code, otherwise a system installed one could be used that gives slightly different outputs.

  • Scons: Allow disabling to enforce no warnings for C compilation

    Currently only for gcc, where we need it until loop tracing is better, we can now use --experimental=allow-c-warnings options to make --debug work for some known currently unavoidable warnings.

  • macOS: Make --macos-create-app-bundle imply standalone mode, it’s not working or useful for accelerated mode anyway.

  • Standalone: Added support for using self-compiled Python versions that are not installed on Linux and macOS. This avoids having to do make install and can ease debugging with changes made in Python core itself. Added in 1.9.6 already.

  • Release: Added ability to simple re-date hotfixes. Previously the version bump commit needed to be dropped, now a fixup commit is easy to generate.

  • Release: Man pages are no longer built during package builds, but are available statically in the git, which should make it easier.

  • Release: Disable verbose output in package installation of Nuitka, it never was any use, and just makes things hard to read.

  • UI: Check user yaml file present immediately. Otherwise it was crashing when parsing yaml files first time with less comprehensible exceptions. Added in 1.9.7 already.

  • Quality: Updated to latest rstfmt, black and isort versions.

  • Debian: Remove references to PDF documentation that no longer exists.

  • Quality: Do not crash when collecting modified files due to deleted files.

  • UI: Detect the Alpine flavor of Python as well.

  • UI: Detect manylinux Pythons as a Python flavors as well.

  • UI: Detect self compiled uninstalled Python as a dedicated flavor.


  • For the Nuitka-Action part of the available options is now generated from Nuitka option definitions itself, adding some previously missing options as a result. As a result, adding --include-onefile-external-data was automatic this time.

  • The warnings for onefile only options without onefile mode provided have been moved to common code, and in some cases were having wrong texts corrected.

  • Use enum definitions in the Nuitka package configuration schema rather than manual oneOf types.

  • The User Manual was proof read and had a bunch of wordings improved.

  • Cleanup, avoid “unused but set variable” warning from the C compiler for hard some forms of hard imports.

  • Prefer os.getenv over os.environ.get for readability.

  • Changed parts of the C codes that clang-format had a hard time with to something more normal.


  • When locating the standalone binary created, use a compilation report and resolve the path specified there. This allows macOS app bundles to be used in these tests as well.

  • Made the PyQt tests executable on macOS too adding necessary options.

  • Added reference test case for unpacking into a list, this was not covered but under suspect of reference leaking which turns out to be wrong.

  • Much enhanced usage of virtualenv in the distutils test cases. We make more sure to delete them even in case of issues. We disable warnings during Nuitka package installation. The code to execute a case was factored out and became more clear. We now handle errors in execution with stating what case actually failed, this was a bit hard to tell previously. Also do not install Nuitka when a pyproject case is used, since the build tool installs Nuitka itself.


This release deserves the 2.0 marker, as it is ground breaking in many ways. The loop type analysis stands out on the optimization front. This will open an avenue for much optimized code at least for some benchmark examples this summer.

The new features for package configuration, demonstrate abilities to avoid plugins for Nuitka, where those previously would have been used. The new variables and parameters made it unnecessary to have them, and still add compile time variable use and user decisions and information, without them.

The scope of supported Python configurations got expanded a bit, and the the usual slew of anti-bloat work and new packages supported, makes Nuitka an ever more round package.

The improved user dialog with less noisy messages and slightly better coloring, continues a trend, where Nuitka becomes more and more easy to use.

Nuitka Release 1.9

This release has had a focus on improved startup time and compatibility with lazy loaders which has resulted in some optimization. There are also the usual amounts of bug fixes. For macOS and Linux there are lots of improvements that should make standalone mode for them robust with many more configurations.

Bug Fixes

  • Nuitka Action: Fix, the parsing code intended for the github action was not working as advertised. Fixed in 1.8.1 already.

  • Standalone: Follow soundfile change for their DLL names. Fixed in 1.8.1 already.

  • MSYS: Fix, the recent change to detect their Python flavor with 3.11 was done wrong. Fixed in 1.8.1 already.

  • Windows: Ignore MS API DLLs found from %PATH%. We only ignored them because they come from the Windows system folder, but if any program has them, then we did include them. Fixed in 1.8.1 already.

  • Standalone: Fix, calendar is used by time built-in module actually and therefore must be included. Fixed in 1.8.1 already.

  • Standalone: Added data file for unstructured package. Fixed in 1.8.1 already.

  • Standalone: Added data file for grpc package. Fixed in 1.8.1 already.

  • Standalone: Added missing dependency for skimage. Fixed in 1.8.1 already.

  • Python3.11: The dictionary copy code could crash on special kinds of dictionaries. Fixed in 1.8.2 already.

  • Standalone: Added data file required by ens of web3 package. Fixed in 1.8.2 already.

  • Fix, multiprocessing could not access attributes living in __main__ module, but only things elsewhere, breaking minimal examples. Fixed in 1.8.2 already.

  • Reports: Fix, the license of some packages in case it is UNKNOWN was not handling all the cases that wheels expose. Fixed in 1.8.2 already.

  • Fix, using --include-module and --include-package was behaving identical for packages. Made the former not include all of the package, but only the top level and what that uses.

  • Standalone: Added support for the lightning package. Fixed in 1.8.3 already.

  • Distutils: Fix, the platform tag was sometimes incorrect for wheels built. Fixed in 1.8.3 already.

  • Compatibility: Make the PySide2/PySide6 signal connection workaround more robust. It was not handling reuse of the same method properly and insisted on changing __name__ which some objects apparently dislike a lot. Fixed in 1.8.4 already.

  • Windows: Fix, need to use short path for the Python installation prefix, as it might be unicode path as well. Fixed in 1.8.4 already.

  • Fix, output spec %NONE% was not compiling anymore. Fixed in 1.8.4 already.

  • Reports: Avoid having short paths for DLL sources on Windows. Fixed in 1.8.4 already.

  • Fix, catch provided metadata from command line --include-distribution-metadata without including the package at runtime. Fixed in 1.8.4 already.

  • Python3.10+: Fix, was not properly initializing indicator variable used in the match re-formulation. The generated code still work, but this was an error on the logical level to use a variable un-initialized. Fixed in 1.8.4 already.

  • Standalone: Added missing DLLs for rlottie-python. Fixed in 1.8.4 already.

  • Standalone: Added missing implicit dependencies and also avoid duplication of DLLs for the av package. Fixed in 1.8.4 already.

  • Fix, was not handling errors when creating distribution objects. Fixed in 1.8.4 already.

  • macOS: Remove extended attributes from DLLs, e.g. finder can add them and it prevents code signing. Fixed in 1.8.4 already.

  • macOS: Workaround for signing tkinter data files properly, we just exclude the problematic ones, as they are going to be unused. Fixed in 1.8.4 already.

  • Standalone: Added hidden dependency of curl_cffi package. Fixed in 1.8.5 already.

  • Standalone: Added hidden dependency of tensorflow package. Fixed in 1.8.5 already.

  • Standalone: Added more kivymd data files. Fixed in 1.8.5 already.

  • Standalone: Added implicit dependency for winloop package. Fixed in 1.8.6 already.

  • Windows: Fix, do not resolve main program executable filename to long filename. Fixed in 1.8.5 already.

  • Windows: Fix, ignore ucrtbase runtime DLLs found from %PATH% as well. Fixed in 1.8.6 already.

  • Compatibility: Fix, the dill-compat plugin was regressed and support for dill version 0.3 was added.

  • Fix, need to include package name for joblib usage with --python-flag=-m to work properly.

  • Windows: Added support for newest joblib too, we no longer need to error for using the latest one.

  • Fix, attribute lookups becoming hard through node factories didn’t annotate possible exceptions.

  • Standalone: Added support for huggingface_hub vendored lazy loader variant.

  • Standalone: Added support for datasets module.

  • Plugins: Handle default plugin of matplotlib a lot better. Be more graceful when the query of the default one fails, and point to MPLBACKEND usage. Otherwise inform the user of the backend used for matplotlib so it can be checked.

  • Fix, --include-module on a package was including all of it rather than just top level, which was what it should do. For including the full package, there is --include-package instead.

  • macOS: Fix, need to check dependencies for the selected target arch precisely, otherwise DLLs and extension modules for the other arch can cause errors for our dependency analysis in standalone mode.

    • Also added support for getting DLL exported symbols on macOS which then allows to properly distinguish extension modules from mere DLLs on macOS, and not just Linux.

  • MSYS2: Fix, the GTK DLL name changed again.

  • Compatibility: Added support for .zip files being in python path as well.

  • Fix, when a sub-package module import is rejected for whatever reason, the programs attempt to import it, still implies an attempt to import the parent module. For extension modules in accelerated mode, this is of course common, but the containing package if any, is of course still to be included.

  • Fix, PySide6 in accelerated mode needs workarounds too, previously only standalone mode was avoiding the corruptions it was causing.

  • Fix, make the PySide2/PySide6 signal connection workaround also fix disconnection only. For signals that only ever got disconnected, but never connected, the workaround was not applied.

  • MSYS2: For standalone add more GI dlls.

  • Fix, inline copies of e.g. tqdm could be detected during compilation and even in place of the real package.

  • Standalone: Added proper support for timm without disabling JIT generally.

  • Python3.11: Fix, frozen stdlib modules must be turned off

    Otherwise the value of os.__file__ becomes wrong, and maybe more issues, as Nuitka is more compatible to full modules than the frozen modules are for standalone mode at least.

  • Python2: Avoid RuntimeWarning when using inline copy of tqdm.

  • Standalone: Added support for newer pydantic and its lazy loader.

  • Standalone: Add config for font data files of qtawesome package.

  • Plugins: Added workaround for PySide6 enums checking bytecode when some older enum values are used. The PySide6 means to detect method calls vs. type lookups to decide if to inject the default value for a flag value. With our workaround, enums behave as expected without that check being possible.

  • Standalone: Added support for gradio package.

  • Python3.6+: Added support for non-latin (for example Chinese) module names, these were not working correctly yet.

  • Python3: Fix, star importing from modules with non-UTF8 encodable names in the module dictionary crashed.

  • Python2: Fix, couldn’t list directories with unicode filenames in them, so that e.g. a Python3 created build directory with unicode module names was not possible to fully delete.

  • Compatibility: Added missing as_posix method to our resource reader objects.

  • Standalone: Added missing DLLs for PyAutoIt package.

  • Standalone: Added data files for the flask_restx package, for which --include-package-data also wouldn’t work, due to its strange handling when running in frozen mode.

  • Standalone: Added more metadata requirements for transformers package.

  • Standalone: Added support for newer transformers package.

  • Standalone: Added data files for yapf vendored lib2to3 package.

  • Plugins: Fix, was crashing on module patterns of submodules not existing in the yaml config implicit dependencies.

New Features

  • Plugins: Introduce an explicit hard import registry, that now can be expanded at compile time by plugins.

  • Plugins: Added support for lazy delayed loading, which removes the need for include-pyi-file as we inline its effect at compile time. Also, the dependencies of these kinds of packages no longer need to be overreaching and can analyze the code again. This is using the hard import registry plugin interface.

  • Linux: Standalone builds with PyPI packages no longer include system DLLs unless a new Yaml configuration for DLLs called package-system-dlls is configured, which will be necessary for GTK bindings probably. With this the included DLLs will more often be only ones suitable for use on other OSes. This should make Linux standalone somewhat easier, but still need to compile on old OS.

  • Reports: For distributions include the installer name, so we can tell pip, conda or system packages apart better.

  • Reports: For included modules, we now also attribute the distributions it directly uses modules from and the distribution the module itself belongs to was added as an attribute as well.

  • Reports: Added excluded module reasons to reporting, so that it can be told directly, which imports were found, but not followed to. Also added report reader capable of providing information from a compilation report.

  • Added support for FIPS compliance, a US security standard by NIST, that caused parts of Python used by Nuitka to be flagged.

  • Watch: Added option to control the update mode, handles now rc versions, so it can be used before and after Nuitka releases easily.

  • Watch: Added timeout for how long programs are allow to run.

  • Watch: Added ability to recognize fork loops happening, so test cases of e.g. joblib do not suddenly go wild on a break change in that or other packages.

  • macOS: The --list-package-dlls now needs to check target arch options, so we now delay the non-compiling options execution until it’s set, which also makes it cleaner code. Also, we can now distinguish real Python extension modules from mere DLLs on macOS too.

  • Standalone: Also ignore av and cv2 DLL collisions, making it more generic.

  • Standalone: Make tk-inter plugin more robust. Detect the tkinter version used and scan for its paths. Use path used when compiling tcl from source and check data directory paths for tcl and tk for expected files, and error out if they are not found. With these changes self-compiled Python as e.g. used in our commercial Linux container is supported too now.

  • Enhanced support for self compiled Python by using link libraries needed for static linked extension modules. This allows a better commercial Linux container build mainly.


  • Optimization: Enhanced handling of aliased variables.

    Was not converting variable assignments from variables created during re-formulations to the dedicated nodes, potentially missing out on optimizations specific to that case, because it was then not recognized to be non-generic anymore later.

    Was not optimizing comparisons and truth checks for temporary variable references, missing out a lot of opportunities for optimization of code coming from re-formulations.

    When a variable is aliased, but the source variable is one that cannot escape or is even very hard value, we were not annotating that as well as possible, but now e.g. comparisons with constant values that are immutable are done even if aliased.

    Remove knowledge of variables assigned to other variables only if that value can actually escape, otherwise that has no real point.

  • Use variable length encoding for data blob size values. This removes size constraints in some cases, but also makes the representation of list, tuple, dict more compact, since they commonly have only a few elements, but we used 4 bytes for length, where the average should be close to one 1 byte per length item now.

  • Faster CRC32 with zlib, leading to much faster program startup, and faster checksums for cached mode of onefile, improving that a lot as well.

  • Windows: Updated MinGW64 to latest winlibs package, should produce even faster code and show stopping bugs in its binutils have apparently been fixed. This should now link a lot faster with LTO, due to using multiple processes.

  • Added support for as hard import to open.

  • Scalability: Make sure we actually use __slots__ for our classes. Variables, code generation context, iteration handles, and type shapes didn’t really use those and that should speed their use up and therefore reduce Python compile time and memory usage.

  • Standalone: Removed one more automatic stdlib module textwrap as it otherwise uses a runner code with test code that is bloating with hello world code.

  • Fedora: Enabled LTO linking by default as well, it’s working, but Fedora Python is still not really good to use, since it doesn’t allow static linking of libpython.

  • Anti-Bloat: Avoid pytest usage in pooch package. Added in 1.8.1 already.

  • Anti-Bloat: Remove pdb usage from pyparsing package. Added in 1.8.2 already.

  • Anti-Bloat: Remove unittest usage in bitarray. module. Added in 1.8.2 already.

  • Anti-Bloat: Avoid lightning to cause use of its lightning.testing framework.

  • Anti-Bloat: Added override that that torch but only it can use unittest, it will not work otherwise.

  • Anti-Bloat: Avoid using IPython in gradio package.

  • Anti-Bloat: Avoid using IPython in altair package.

  • Anti-Bloat: Avoid using numba in pyqtgraph package.

  • Anti-Bloat: Avoid using triton in torch package.

  • Anti-Bloat: Avoid using unittest in multiprocess package.

  • Anti-Bloat: Avoid using setuptools with new mmcv package as well.

  • Anti-Bloat: Avoid URLs in numpy messages.

  • Code Generation: Dedicated helper function for fixed imports, that uses less C code for standard imports.

  • Standalone: Avoid including libz on Linux.

  • Quality: Use latest isort and rstchk versions.


  • Python3.12: Mark as unsupported for now, it does not yet compile on the C level again.

  • User Manual: Added description of deployment mode, this was not documented so far, but for some programs, dealing with them is now required.

  • User Manual: Improved --include-plugin-directory documentation to make it more clear what it is usable for and what not.

  • UI: Reject standard library paths for plugin directories given to --include-plugin-directory which is a frequent user error.

  • UI: When interrupting during Scons build with CTRL-C do not give a Nuitka call stack, there is no point in that one, rather just exit with a message saying the user interrupted the scons build.

  • UI: Make package data output from --list-package-data more understandable.

    We already had a count for DLLs too, and should not list directory name in case it’s empty and has no data files, otherwise this can confuse people.

  • UI: Make the progress bar react to terminal resizes. This avoids many of the distortions seen in Visual Code that seems to do it a lot.

  • UI: Added a mnemonic warning for macOS architecture cross compilation, that it will only work as well as Python does when limited to that arch. Read more on the info page for detailed information. Added in 1.8.4 already.

  • UI: Error exit for wrong/non-existent input files first. Otherwise e.g. complaints about not including anything can be given where project options were intended to solve that.

  • UI: Enhanced error message in case of not included imageio plugins. Added in 1.8.4 already.

  • UI: Enhanced messages from options nanny, showing the condition that was not passed.

  • UI: Improved download experience. When hitting CTRL-C during a download, delete the incomplete file immediately, otherwise it’s causing an error next run. Also added progress for downloads as well, so they do not sit there silent without a way to know how much is remaining.

  • UI: Also report errors happening during plugin init nicely.

  • Visual Code: Added ignore paths code spell checking. This only adds the most obvious things, more to come later.

  • Visual Code: Use environment for C include path configurations, and add one for use on macOS, this cleaned up a lot of inconsistencies in paths for the various existing platforms.

  • Debugging: Added experimental switch to disable free lists, so memory corruption issues can become easier to debug.

  • UI: Output clang and gcc versions in --version output as well.

  • UI: Add hint how to disable the warning message that asks to disable the console during debugging by explicit --enable-console usage.

  • UI: Do not consider aliases of options for ambiguous option error. Without this --no-progressbar and --no-progress-bar being both accepted, forced long version of options for no good reason.

  • Debugging: With --debug output failed query command that a plugin made. In this way it is easier to check what is wrong about it for the user already.

  • UI: Check if metadata included has the actual distribution package included. Otherwise we error out, as this would result in a RuntimeError when the program is attempting to use it.

  • UI: Harmonized help text quoting. We will also need that in order to generate the help texts for Nuitka-Action in the future. Currently this is not perfect yet.

  • Debugging: Added trace that allows us to see how long Py_Exit call takes, which might be a while in some cases.

  • User Manual: Made the Nuitka requirements top level chapter.

  • User Manual: Added promise to support newer Python versions as soon as possible.

  • User Manual: Added section about how Linux standalone is hard and needs special care.

  • Python3.11: Disallow to switch to g++ for too old gcc, with this Python version we have to use C11.

  • Quality: Remove inconsistencies with C python hex version literals in auto-format, which will also make searching code easier.

  • UI: More clear error message for asking package data of a module name that is not a package.


  • Dedicated node for fixed and built-in imports were added, which allow the general import node to be cleaner code.

  • Scons: Removed remaining win_target mode, this is long obsolete.

  • Spelling improvements by newer codespell, and generally, partially ported to 1.8.4 already so the Actions pass again.

  • Plugins: Move python code of dill-compat run time hook to separate file.


  • Run the distutils tests on macOS as well, so it’s made sure wheel creation is working there too, which it was though.

  • Avoid relative URLs in use during pyproject.toml tests, these fail to work on macOS at least.

  • Add GI GTK/GDK/Cairo standalone test for use with MSYS2. Eventually this should be run inside Nuitka-Watch against MSYS2 on a regular basis, but it doesn’t support this Python flavor yet.

  • Added test case with Chinese module names and identifiers that exposed issues.

  • Completed the PGO test case and actually verify it does what we want.

  • Added standalone test for setuptools. Since our anti-bloat works makes it not compiled with most packages, when it is, make sure it doesn’t expose Nuitka to some sort of issue by explicitly covering it.

  • Show tracebacks made in report creations on GitHub Actions and during RPM builds.


This is again massive in terms of new features supported. The lazy loader support is very important as it allows to handle more packages in better ways than just including everything.

The new added optimization are nice, esp. startup time will make a huge difference for many people, but mainly the focus was on supporting packages properly, and getting Nuitka-Watch to be able to detect breaking of packages from PyPI closer to when it happens.

And then of course, there is a tremendous amount of improvements for the UI, with lots features become even more rounded.

For Python 3.12 work has begun, but there is more to do for it. At this time it’s not clear how long it takes to add it. Stay tuned.

Older Releases

These are older releases of Nuitka.

Nuitka Release 1.8

Bug Fixes

  • Standalone: Added support for opentelemetry package. Added in 1.7.1 already.

  • Reports: Fix, do not report plugin influence when there are not no-auto-follow in an anti-bloat section. Fixed in 1.7.2 already.

  • Anti-Bloat: Add missing usage tag use_pytest for anti-bloat changes that remove pytest related codes. Fixed in 1.7.2 already.

  • Standalone: Added support for newer jsonschema package. Fixed in 1.7.2 already.

  • Standalone: Fix, our iterdir implementation was crashing in files for packages that don’t actually have a directory for data files to live in. Fixed in 1.7.2 already.

  • Fix, parent package imports could pick the wrong name internally and then collide with sub-packages of that package during collision. Fixed in 1.7.3 already.

  • Standalone: Added support for pymssql package. Fixed in 1.7.3 already.

  • Standalone: Added support for cvxpy package. Fixed in 1.7.4 already.

  • Standalone: Added missing dependencies of lib2to3.refactor. Fixed in 1.7.4 already.

  • Standalone: Fix, data files for lib2to3.pgen were regressed. Fixed in 1.7.4 already.

  • Standalone: Added missing dependency of cairo package. Fixed in 1.7.4 already.

  • Standalone: Added support for new trio package. Fixed in 1.7.4 already.

  • Standalone: Added support for markdown package. Fixed in 1.7.4 already.

  • Standalone: Added support to eventlet package. Fixed in 1.7.4 already.

  • Standalone: Added support for more newer sklearn package. Fixed in 1.7.5 already.

  • Standalone: Added support for more newer skimage package. Fixed in 1.7.5 already.

  • Standalone: Added support for more newer transformers package. Fixed in 1.7.5 already.

  • Standalone: Added support for torch_scatter package. Fixed in 1.7.6 already.

  • Standalone: Added missing DLL for wx.html2 to work well on Windows. Fixed in 1.7.6 already.

  • Fix, the @pyqtSlot decoration could crash the compilation and was effective even if no pyqt plugin was active. Fixed in 1.7.6 already.

  • Python3.11: Fix, need to support BaseExceptionGroup for code generation too, otherwise the exceptiongroup backport was not working. Fixed in 1.7.7 already.

  • MSYS2: Fix usage of deprecated sysconfig variable with mingw. After their switch to Python 3.11, it is no longer available. Fixed in 1.7.7 already.

  • Distutils: Do not compile empty directories found in package scan as namespaces. Fixed in 1.7.7 already.

  • Python3.7+: Fix, need to follow dict internal structure more correctly, otherwise we over-allocate and copy more data than necessary. Fixed in 1.7.7 already.

  • Python3.8: Fix, the new pyqt plugin workaround requires 3.9 or higher and could causes compile time crashes with the @pyqtSlot decorator. Fixed in 1.7.7 already.

  • Modules: Fix, the .pyi file created was using default encoding which can vary and potentially even crash on other systems. Enforcing utf-8 now. Fixed in 1.7.8 already.

  • Fix, only failed relative imports should become package relative. This was giving wrong names for attempts imports in these cases. Mostly only affected dependency caching correctness and reporting at this time. Fixed in 1.7.8 already.

  • Standalone: Added missing metadata dependencies for transformers package. Fixed in 1.7.9 already, but more added for release.

  • Fix, need to ignore folders that cannot be module names in stdlib. Could e.g. crash when encountering folders like .idea which cannot be module names. Fixed in 1.7.9 already.

  • Standalone: Added data files for langchain package. Fixed in 1.7.10 already.

  • Fix, forced output paths didn’t work without C11 mode. This mainly affected older MSVC users, with newer MSVC and good enough Windows SDK, it’s not using C++ anymore. Fixed in 1.7.10 already.

  • Fix, was using int values for boolean returns, something that was giving warnings with at least older MSVC not in C11 mode. Fixed in 1.7.10 already.

  • Fix, failed hard name imports could crash with segfault trying to release their value. Fixed in 1.7.10 already.

  • Standalone: Added missing implicit dependency for xml.sax in stdlib. Fixed in 1.7.10 already.

  • Windows: Fix, --mingw64 mode was not working if MSVC was installed, but not acceptable for use. Fixed in 1.7.10 already.

  • Standalone: Fix, onnxruntime had too few DLLs included. Fixed in 1.7.10 already.

  • Standalone: Added support for moviepy. Fixed in 1.7.10 already.

  • Python3.10+: Fix, matching empty sequences was not considering length, leading to incorrect code execution for that case.

    match x:
       case []:
             ... # non-empty sequences matched here
  • UI: Fix, some error outputs didn’t work nicely with progress bars, need to use our own print function that temporarily disables them or else outputs get corrupted.

  • Linux: Sync output for data composer. This is to avoid race conditions that we might have been seeing occasionally.

  • Compatibility: Fix, the sys.flags.optimize value for --python-flag=-OO didn’t match what Python does.

  • Standalone: Fix, packages have no __file__ if imported from frozen, these was causing issues for some packages that scan all modules and expect those to be there.

  • Fix, the dict built-in could crash if its argument self-destructs during usage.

  • Fix, the PySide2/PySide6 workaround for connecting compiled class methods without crashing were not handling its optional type argument.

  • Enhanced non-commercial PySide2 support by adding yet another class to be hooked. This was ironically contributed by a commercial user.

  • Standalone: Added support for newer delvewheel version as used in newest scipy and probably more packages in the future.

  • Compatibility: The pkgutil.iter_modules function now works without importing the module first. The makes Faker work on Windows as well.

  • Reports: Detect top level packages even with broken packaging. Some packages will not reveal through installed files or top level what package they are for, and as a result, they cannot be uninstalled, but we need to still be able guess what package they are responsible for, so we go by their PyPI name, which works for tensorflow.

  • Compatibility: More robust way of allowing iteration of compiled packages via file path.

    Rather than pre-populating the cache, we should provide the hook function to check if we are responsible for a given path. With this, the Faker package works on Windows as well now, and probably other packages benefit too. This then works on paths rather than strings, which due to short paths, etc. can be non-unique on Windows easily.

  • Standalone: Added support for the opencc package.

  • Compatibility: Fix, import name resolving done for things like six and others should be done as soon as possible, and not just during optimization, or else some imports can become just wrong as a result.

  • Python3.11: Added support for the new closure keyword only argument in exec built-in.

  • Standalone: Added support for pythonnet on Linux as well.

  • Debian: Fix, do not give false alarms for root pip installed packages, they get a similar path component, but are not actually Debian packages of course, this was mostly affecting builds inside containers of course.

  • Compatibility: Added support for comparing results from our resource reader file interfaces. This is needed for when people want to e.g. sort the the file list.

  • Python3.6+: Fix, didn’t catch await on module level as a syntax error.

  • Compatibility: Added support for joblib with loky backend as well.

  • Standalone: Added support for newer chromadb adding missing dependencies and data files.

  • Python3.9+: Fix, importlib.resources.files() was not fully compatible

    Need to provide basename for .name attribute rather than an absolute path. And in some cases, a leading trailing slashes was produced for the full path, which caused trouble for file iteration of filenames.

  • Standalone: Added support for newer importlib_resources as well. We now need to expose the files functionality even before Python 3.9 for this to be possible.

  • Standalone: Added support for newer rapidfuzz package.

  • Added support for newer PyOpenGL package.

New Features

  • Plugins: Added support to specify embedding of metadata for given packages via the package configuration. With this, entry points, version, etc. can even be resolved if not currently possible at compile time to so through the code with static optimization. Added in 1.7.1 already.

    - module-name: 'opentelemetry.propagate'
          - 'opentelemetry-api'
  • Distutils: Add PEP 660 editable install support. With this pdm can be used for building wheels with Nuitka compilation. Added in 1.7.8 already.

  • Haiku: Added support for accelerated mode, standalone will need more work, also recognize its form of the site-packages folder, named vendor-packages.

  • Disable misleading initial import exception handling in numpy, all what it says detracts only.

  • Added python flags given for no_asserts, no_docstrings and no_annotations to the __compiled__ attribute values of modules and functions to fully expose the information.

  • Watch: Added capability to specify what nuitka binary to use in nuitka-watch so we can use enhanced nuitka-watch from develop branch with older versions of Nuitka with no issues.

  • Watch: Now evaluates the minimum version needed for Nuitka, and skips test cases, allowing nuitka-watch to be run with versions that do not yet handle cases that e.g. develop already can, i.e. next Nuitka version.

  • Watch: Now evaluates if a compilation with Nuitka needs to be done at all, as it’s only necessary if the PyPI config changed, or if Nuitka version changed.

  • Reports: Added source path for modules, so it’s easier to tell where something came from, and esp. in case of bugs in the import location of Nuitka.

  • Reports: In case of a crash, always write report file for use in bug reporting. This is now done even if no report was asked for.

  • Reports: Include error exit message from Nuitka in case of explicit exits.

  • UI: Added new --deployment and --no-deployment-flag that disables certain debugging helpers.

    Right now, we use this to control a hook that prevents execution of itself with -c which is used by e.g. joblib and that potentially can turns Nuitka created programs into a fork bombs, when they use sys.executable -c .... This can be disabled with --no-deployment-flag=self-execution or --deployment.

    The plan is to expand this to cover FileNotFoundError and similar exception exits pointing to compilation issues with helpful more annotations.

  • Catch attempts to exec compiled function bytecodes.

    This segfaults otherwise with at least Python3.11 and is probably a good idea to catch for all versions, as it doesn’t do anything.

  • Windows: Remove unnecessary .\ in CMD files generated, these will otherwise show up in sys.argv[0] too, making them more ugly than necessary.

  • Scons: Also respect CFLAGS setting. It’s rarely used, but for completeness sake we should have that too. The effects are the same as CCFLAGS it seems.


  • Added type shape for built-in hash operation, these must indeed be of int type either way.

  • Anti-Bloat: Avoid using unittest in future and multiprocessing package. Added in 1.7.3 already.

  • Anti-Bloat: Avoid using unittest in git package. Added in 1.7.3 already.

  • Anti-Bloat: Avoid IPython in streamlit package.

  • Standalone: Make transformers work with no_docstrings mode. Added in 1.7.7 already.

  • Anti-Bloat: Avoid more IPython usage in transformers package.

  • Anti-Bloat: Avoid using pytest in polyfactory package.

  • Anti-Bloat: Expand the list of modules that are in the unittest group by the ones Python provides itself,, test.test_support and, so the culprits are more easily recognizable.

  • Anti-Bloat: Treat ipykernel and jupyter_client as equal to IPython for usage, so the bloat warning about IPython becomes more meaningful in that case too.

  • Anti-Bloat: Avoid using IPython in plumbum package.

  • Statically optimize the value of sys.byteorder as well.

  • Anti-Bloat: Added no-auto-follow for tornado in joblib package. The user is informed of that happening if nothing else imports tornado in case he wants to enable it.

  • Standalone: Avoid including standard library zipapp or calendar automatically and remove their runners through anti-bloat configuration. This got rid of argparse for hello world compilation.

  • Standalone: Do not auto include standard library json.tool which is a binary only.

  • Standalone: Avoid automatic inclusion a _json extension module for the json module and do not automatically include it as part of stdlib anymore, this can reduce the size of standalone distributions.

  • Standalone: Avoid the standard library audioop extension module by making all audio related modules non-automatically included.

  • Standalone: Avoid the _contextvars standard library extension module. Explicit and implicit imports of contextvar module will continue to work and hopefully give proper errors until we do ourselves raise such errors.

  • Standalone: Avoid also the “_crypt” standard library extension module, and make the crypt module raise an error where we modify the message to not be as misleading.

  • Standalone: On macOS we also saw _bisect, _opcode and more modules that are optional extension modules, that we no longer do automatically use if they are that way.

  • Standalone: Added more modules like mailbox, grp, etc. to exclusion from standard library when they trigger dependencies on other things, or are an extension themselves.

  • Anti-Bloat: Avoid using sqlalchmy.testing and therefore pytest in sqlalchemy package. Also added that testing package to be treated as using pytest. Added in 1.7.10 already.

  • Anti-Bloat: Avoid IPython in distributed package. Added in 1.7.10 already.

  • Anti-Bloat: Avoid dask usage in skimage. Added in 1.7.10 already.

  • Anti-Bloat: More changes needed for newer sympy to avoid IPython. Added in 1.7.10 already.

  • Anti-Bloat: Enhanced handling of PIL.ImageQt even without the Qt binding plugins being active.

  • Anti-Bloat: Do not automatically follow matplotlib from scipy as that is code that will only be used if other code using it exists too.

  • Anti-Bloat: Avoid pandas and matplotlib for sklearn package. Availability checks of third party packages should be counted as real usage.

  • Anti-Bloat: Avoid IPython in newer keras module too.

  • Anti-Bloat: Updated for newer tensorflow package, also using more robust new form of no-auto-follow to achieve that.

  • Anti-Bloat: Avoid using Qt bindings for as it’s only useful if one of our Qt plugins is active.


  • User Manual: Make it clear in the example that renaming created extension modules to change their name does not work, such that the user has to first rename the Python module properly.

  • macOS: Pronounce Homebrew as somewhat support but not recommended due to its limited results for portability.

  • UI: Added mnemonic for unsupported Windows store Python, so we have a place to give more information. Read more on the info page for detailed information.

  • UI: Disable warning for numpy/scipy DLL non-identity conflicts. These are very common unfortunately and known to be harmless.

  • Stop creating PDFs for release. They are not really needed, but cause extra effort that makes no sense.

  • Quality: Updated to latest black which removes some leading new lines in blocks, changing a bunch of files. Bumped development requirements file Python version to 3.8, since black won’t do 3.7 anymore.

  • Quality: Updated to latest PyLint, no changes from that.

  • Quality: Auto-format the markdown files used for GitHub templates as well.

  • Debugging: Catch errors during data composer phase cleaner. Added in 1.7.1 already.

  • Plugins: More clear error messages for Yaml files checker. Added in 1.7.5 already.

  • Release: Avoid DNS lookup by container, these sometimes failed.

  • UI: Catch user error of compiling in module mode with unknown file kinds, it needs to be Python code of course.

  • UI: In case of SyntaxError in main file, always suggest latest supported version. Previous it was toggling between Python2 and Python3, but that’s no longer the main reason this happens.

  • UI: Fix typo in help output for --trademarks option. Added in 1.7.8 already.

  • UI: Fix, need to enforce version information completeness only on Windows, other platforms can be more forgiving. Added in 1.7.8 already.

  • Visual Code: Enable black formatter as default for Python.

  • UI: Disallow --follow-stdlib with --standalone mode. This is now the default, and just generally makes no sense anymore.

  • Plugins: Warn if Qt qml plugins are not included, but qml files are. This has been a trap for first time users for a while now, that now have a way of knowing that they need to enable that Qt plugin feature.

  • Plugins: Enhanced Qt binding plugins selection by the various qt plugins

    Now can also ask to not include specified plugins with --noinclude-qt-plugins and by now include sensible by default, with the --include-qt-plugins=qml line not replacing it, but rather extending it. That makes it easier to handle and catches a common trap, where users would only specify the missing plugin, but remove required plugins like platform making it stop to work.

  • Plugins: Allow plugins provide None for flags not just by return value length, but also an explicit value, so plugin code can make a difference in a consistent way.

  • UI: Lets have the options-nanny output the failed condition, so it’s more clear what the issue is.

  • Quality: Unified spell checker markers to same form in all files through auto-format for more consistency.

  • Quality: Always avoid attempting to format executables, much like we already do for bytecode, otherwise some attempts on them can crash.

  • Windows: Only change directory to short path during execution of Scons, we are otherwise leaking it to --run execution in tests, giving their output comparison a harder time than necessary.

  • Scons: Use report paths for outputs of filenames in slow compilation messages as well.

  • WinPython: Adapted detection of this flavor to changes made in that project.


  • Major Cleanup, do not treat technical modules special anymore

    Previously the immediate demotion of standard library to bytecode is not really needed and prevented dependency analysis. We have had plenty issues with that ever since not all stdlib modules were automatic anymore, there was a risk of missing some of them, just because this analysis was not done.

    Moved the import detection code to a dedicated module cleaning up the size of the standalone mechanics, as it also is not exclusive to it.

    Adding “reasons” to modules, different from “decision reasons” why something was allowed to be included, these give the technical reason why something is added. This is needed for anti-bloat to be able to ignore stdlib being added only for being frozen.

    Now we are correctly annotating why an extension module was included, e.g. is it technical or not, that solves a TODO we had.

    Removes a lot of code duplication for reading source and bytecode of modules and the separate handling of uncompiled modules as a category in the module registry is no more necessary.

    The detection logic for technical modules itself was apparently not robust and had bugs to be fixed that became visible now, and that make it unclear how it ever worked as well.

  • Refactor towards unification of statement and expression.

    Make sure Make existing statement operations, i.e. use the function intended for them so they are immediately closer to what expressions do, and don’t visit their own children themselves anymore.

    Remove checks for expression or statement, we won’t use that anymore, and it’s only costing performance until we merge them.

  • The caching (currently only used when demoting to bytecode), was not keeping track of distributions attempted to be used, but then being not found. That could have led to errors when using the cached result.

  • Again some more spelling fixes in code were identified and fixed.

  • Removed now unused user provided flag from uncompiled module nodes.

  • Removed 3.3 support from test runner as well.

  • Avoid potential slur word from one of the tests.


  • Sometimes the pickle from cached CPython executions cannot be read due to protocol version differences, then of course it’s also not usable.

  • Added CPython311 test suite, but it is not yet completely integrated.

  • Tests: Salvage one test for dateutil from a GSoC 2019 PR, we can use that.


This is massive in terms of new features supported. The deployment mode being added, provides us with a framework to make new user experience with e.g. the missing data files, much more generous and help them by pointing to the right solution.

The technical debt of immediate bytecode demotion being removed, is huge for reliability of Nuitka. We now really only have to deal with actual hidden dependencies in stdlib, and not just ones caused by us trying to exclude parts of it and missing internal dependencies.

Nuitka Release 1.7

There release is focused on adding plenty of new features in Nuitka, with the new isolated mode for standalone being headliners, but there are beginnings for including functions as not compiled, and really a lot of new anti-bloat new features for improved handling, and improving user interaction.

Also many packages were improved specifically to use less unnecessary stuff, some of which are commonly used. For some things, e.g. avoiding tkinter, this got also down to polishing modules that have GUI plugins to avoid those if another GUI toolkit is used.

In terms of bug fixes, it’s also a lot, and macOS got again a lot of improvements that solve issues in our dependency detection. But also a long standing corruption for code generation of cell variables of contractions in loops has finally been solved.

Bug Fixes

  • Python3.11: The MSVC compiler for Windows will not work before 14.3 (Visual Studio 2022) if used in conjunction with Python 3.11, point it out to the user an ignore older versions. Fixed in 1.6.1 already.

  • Standalone: Added support for the pint package. Fixed in 1.6.1 already.

  • Standalone: Added missing standard library dependency for statistics. Fixed in 1.6.1 already.

  • Compatibility: Fix, the transformers auto models were copying invalid bytecode from compiled functions. Added workaround to use compiled function .clone() method. Fixed in 1.6.1 already.

  • Compatibility: Added workaround for scipy.optimize.cobyla package. Fixed in 1.6.1 already.

  • Anaconda: Detect Anaconda package from conda install vs. PyPI package from pip install, the specifics should only be applied to those. Adapted our configurations to make the difference. Fixed in 1.6.1 already.

  • Anaconda: Do not search DLLs for newer shapely versions. Fixed in 1.6.1 already.

  • Standalone: Add new implicit dependencies for pycrytodome.ECC module. Fixed in 1.6.1 already.

  • Standalone: Fix tls_client for Linux by not non-Linux DLLs. Fixed in 1.6.1 already.

  • MacOS: When using --macos-app-name, the executable name of a bundle could become wrong and prevent the launch of the program. Now uses the actual executable name. Fixed in 1.6.1 already.

  • Multidist: The docs didn’t properly state the option name to use which is --main and also it didn’t show up in help output. Fixed in 1.6.2 already.

  • Standalone: Added support for polars package. Fixed in 1.6.3 already.

  • Standalone: Added implicit imports for apscheduler triggers. Fixed in 1.6.3 already.

  • Standalone: Add data files to AXML parser packages. Added in 1.6.4 already.

  • Fix, exec nodes didn’t annotate their exception exit. Fixed in 1.6.4 already.

  • Standalone: Added data files for open_clip package. Fixed in 1.6.4 already.

  • Standalone: Avoid data files warning with old pendulum package. Fixed in 1.6.4 already.

  • Standalone: Added implicit dependencies for faker module. Fixed in 1.6.4 already.

  • Added workaround for opentele exception raising trying to look at the exception frame before its raised. Fixed in 1.6.4 already.

  • Nuitka-Python: Do not check for unknown built-in modules. Fixed in 1.6.4 already.

  • Scons: Fix, the total ccache file number given could be wrong. Ignored messages were counted still as compiled, leading to larger sum of files than actually there was. Fixed in 1.6.5 already.

  • Fix, multiprocessing resource tracker was not properly initialized. On at least macOS this was causing it to work relatively badly, because it could fail to actually use it. Fixed in 1.6.5 already.

  • Standalone: Added support for cassandra-driver package. Fixed in 1.6.5 already.

  • Onefile: Have Python process suicide when bootstrap surprisingly died, respecting the provided grace time for shutdown. Fixed in 1.6.5 already.

  • Plugins: Fix, package versions for at least Ubuntu packages can be broken, such that at least pkg_resources rejects them. Handle that and use fallback to next version detection method. Fixed in 1.6.5 already.

  • Onefile: Handle SIGTERM and SIGQUIT just like SIGINT on non-Windows. The Python code with see KeyboardInterrupt for all 3 signals, so it’s easier to implement. Previously onefile would exit without cleanup being performed. Fixed in 1.6.5 already.

  • Standalone: Fix, need to add more implicit dependencies for pydantic because we do no longer include e.g. decimal and uuid automatically.

  • Standalone: Added missing implicit dependencies for fiona package. Added in 1.6.6 already.

  • Standalone: Added missing implicit dependencies for rasterio package. Added in 1.6.6 already.

  • Standalone: Fix, need to add more implicit dependencies for pydantic. Added in 1.6.6 already.

  • Fix, the data composer used a signed value for encoding constant blob sizes, limiting it needlessly to half the size possible.

  • Windows: Avoid dependency on API not available on all versions, specifically Windows 7 didn’t work anymore. With this, symlinks are only resolved where they actually exist, and MinGW64 does it too now.

  • Standalone: Added support for .location attribute for pkg_resources distribution objects.

  • Anti-Bloat: Avoid using dask and numba in the tsfresh package.

  • Fix, outline cell variables must be re-initialized on entry. The code would be crashing for for outlines used in a loop, since the cleanup code for these cell variables would release the cell that was created during containing scope setup.

  • Standalone: Added missing dependency of pygeos package.

  • Standalone: Added sqlalchemy implicit dependency.

  • Standalone: Added data files for mnemonic package.

  • Fix, attribute checks could cause corruption when used on objects that raise exceptions during __getattr__.

  • Python2: Fix, wasn’t making sure instance attribute lookups were actually only done with str attributes.

  • macOS: Fix, need to allow versioned DLL dependency from un-versioned DLLs packaged.

  • Standalone: Added DLLs for rtree package.

  • Standalone: Added support for newer skimage package.

  • Standalone: Added support for newer matplotlib package.

  • Standalone: Fix, our numpy.testing replacement, was lacking a function assert_array_almost_equal used in at least the pytransform3d package.

New Features

  • Added support for --python-flag=isolated mode. In this mode, packages are not expandable via environment variable provided paths and sys.path is emptied which makes imports from the file system not work.

  • The options for forcing outputs were renamed to --force-stdout-spec and force-stderr-spec to force output to files and now work on non-Windows as well. They kind of were before, but e.g. %PROGRAM% was not implemented for all OSes yet.

  • Capturing of all outputs now extends beyond the Python level outputs is now attempting to capture C level outputs as well. These can be traces of Nuitka itself, but also messages from C libraries. On Windows, with MinGW64 this does not work, and it still only captures MinGW64, due to limitations of using different C run-times. With MSVC it works for the compiled program and C, but DLLs can have their own C runtime outputs that are still not caught.

  • Added new spec value %PROGRAM_BASE% which will avoid the suffix .exe or .bin of binaries that %PROGRAM% will still give.

  • Plugins: Added ability to query if a package in an Anaconda package or not, with the new is_conda_package() function in Nuitka package configuration. Added in 1.6.1 already.

  • Plugins: Provide control tags during plugin startup with new interface, such that these become globally visible.

  • Plugins: Allow to give --include-qt-plugins options of Qt binding plugins to be given multiple times. This is for consistency with other options. These now expand the list of plugins rather than replacing it.

  • Added experimental code to include functions decorated in certain ways to be included as bytecode. Prepare the inclusion as source code in a similar fashion. This was used to make example PyQt5 code work properly with timers where it doesn’t normally work, but is still in development before it will be generally useful. For that it reacts to @pyqtSlot decorators.

  • Plugins: Make anti-bloat not warn when bloating modules include their group. This helps when e.g. distributed is going to use dask, then we warn about distributed, but not anymore, when that then uses dask. And that intention to avoid dask is now in the warning given for distributed.

  • Plugins: Added ability to decide module inclusion based on using module name and not only the used name. This will be super useful to make some imports not count per se for inclusion.

  • Plugins: Added new no-auto-follow Yaml configuration for anti-bloat, that makes imports from one module not automatically included. That can make optional import removal much easier.

  • Plugins: Added new function for when clauses, such that it now can be tested if this Python version has a certain built-in name, e.g. when: 'not has_builtin_module("_socket")' will not apply configuration _socket is an extension module rather than built-in. This can be used to avoid unnecessary changes.


  • Optimization: Better hasattr handling. Added ability for generated expression base class to monitor the attribute name for becoming constant and then calling a new abstract method due to auto_compute_handling saying wait_constant:name.

  • Optimization: Added type shapes for setattr and hasattr built-ins as well as the attribute check node for better code generation.

  • Optimization: Added dedicated nodes for importlib.resources.files to allow including the used package automatically.

  • Standalone: Include only platform DLLs for tls_client rather than all DLLs for all platforms. Added in 1.6.1 already.

  • Anti-Bloat: Avoid including sympy.testing for sympy package. Added in 1.6.3 already.

  • Anti-Bloat: Avoid IPython in transformers package. Added in 1.6.3 already.

  • Anti-Bloat: Avoid transformers.testing_util inclusion for transformers package as it will trigger pytest inclusion.

  • Anti-Bloat: Added missing method to our numpy.testing stub, so it can be used with more packages. Added in 1.6.4 already.

  • Anti-Bloat: Avoid numba usage from parts of pandas. Added in 1.6.4 already.

  • Anti-Bloat: Avoid pytest usage in patsy more completely. Added in 1.6.4 already.

  • Standalone: Added data files needed for pycountry package. Added in 1.6.4 already.

  • Anti-Bloat: Avoid unittest usage in numpy package. Added in 1.6.4 already.

  • Anti-Bloat: Avoid using pytest in statsmodels package. Added in 1.6.4 already.

  • Anti-Bloat: Avoid including PIL.ImageQt when no-qt plugin is used. Added in 1.6.4 already.

  • Anti-Bloat: Avoid IPython usage in dask. We do not cover bloat with dask allowed well yet, more like this should be added. Added in 1.6.5 already.

  • Anti-Bloat: Avoid dask via distributed in fsspec package. Added in 1.6.5 already.

  • Anti-Bloat: Avoid IPython in patsy package. Added in 1.6.5 already.

  • Anti-Bloat: Avoid setuptools in newer torch as well. Added in 1.6.5 already.

  • Anti-Bloat: Avoid tkinter inclusion in PIL and matplotlib if another GUI plugin is active. This is using the control tags made available by GUI plugins.

  • Anti-Bloat: Avoid warning for from unittest import mock imports. These are common, and not considered actual usage of unittest anymore.

  • Anti-Bloat: Avoid pandas usage in tqdm. This uses the new no-auto-follow feature that will enable the optional integration of tqdm if pandas is included by other means only.

  • Anti-Bloat: Better method of avoiding socket in email.utils. With changing the source code to delay the import of socket to the only function using it. Socket is now included only if used elsewhere. These changes however, are only done if _socket if is not a built-in module, because only then they really matters. And using a simple --include-module=socket will restore this. This approach is more robust and less invasive.


  • Added run-inside-nuitka-container for use in CI scripts. With this, dependencies of package building and testing from correct system installation should go away.

  • Release: Add CI container for use with run-inside-nuitka-container to make Debian package releases. This provides a more stable and flexible environment rather than building through ansible maintained environments, since different branches can more easily use different versions, or new features for the container handling.

  • Release: Use upload tokens rather than PyPI password in uploads, and secure the account with 2FA.

  • UI: Avoid duplicate warnings for anti-bloat detected imports. In case of from unittest import mock there were 2 warnings given, for unittest and unittest.mock but that is superfluous.

  • macOS: More beginner friendly version of Apple Python standalone error. They won’t know why it is, and where to get a working Python version, so we explain more and added a download link.

  • Scons: Consider only 5 minutes slow for a module compilation in backend. Many machines are busy or slow by nature, so don’t warn that much.

  • GitHub: Actions no longer work (easily) with Python2, so we removed those and need to test it elsewhere.

  • UI: Output the filename of the XML node dump from --xml as well.

  • UI: Make --edit-module-code work with onefile outputs as well.

  • Debugging: Allow yaml condition traceback to go through in --debug mode, so exception causes are visible.

  • Plugins: Make more clear what is the forbidden module user, such that it is possible to debug it.

  • UI: Inform user about slow linking, and --lto=no choice in case auto was used. This should make this option more obvious for new users that somehow victim of not defaulting to no, but still having a slow link.

  • Debugging: Include PDBs for DLLs in unstripped mode already. Previously this was only done for debug mode, but that’s a bit high of a requirement, and we sometimes need to debug where things do not happen in debug mode.

  • User Manual: Added typical problem with python -m compiled_module execution not working and why that is so.

  • Debian: Do not include PDF files in packages. These are probably not used that much, but they cause issues at times, that are likely not worth the effort.


  • Moved OS error reporting as done in onefile binary to common code for easier reuse in plugins.

  • Moved helper codes for expanding paths and for getting the path to the running executable to file path common code for clearer code structure.

  • Removed x-bits from files that do not need them. For __main__ files, they are not needed, and for some files they were outright wrong.

  • Python3.12: Avoid usage of distutils.utils which were using to disable bytecode compilation for things we expect to not work.

  • Solve TODO and use more modern git command git branch --show-current to detect branch, our CI will have this for sure.

  • In our Yaml configuration prefer the GUI toolkit control tags, e.g. use_pyside6 over the plugin("pyside6") method.


  • Release: Use CI container for linter checks, so different branches can use different versions with less pain involved.

  • macOS: Allow all system library frameworks to be used, not just a few selected ones, there is many of them and they should all exist on every system. Added in 1.6.1 already.

  • Made the pendulum test actually useful to cover new and old pendulum actually working properly.


This release really polished anti-bloat to the point where we now have all the tools needed. Also torch in newest version is now working nicely again with it, and a few rough edges of what we did with 1.6 for not including extension modules were removed. This polishing will go on, but has reached really high levels. More and more people are capable of helping with PRs here.

The optimization work outside of anti-bloat was really minor, with only the two attribute built-in nodes being worked on, and only hasattr seeing real improvements. However, this was more of a structural thing. The wait_constant technique will not get applied more often, but it also will need a wait_all_constant companion, before we can expect scalability improvements.

Restoring Windows 7 is important to many people deploying to old systems, and the like.

However, in the coming release, we need to attack loop tracing. The only bugs currently remaining are related to wrong tracing of items, and it also is a limitation for hard imports to work. So scalability from doing more of the wait_constant work, and from more clever loop tracing shall be the focus of the 1.8 release.

Nuitka Release 1.6

This release bumps the much awaited 3.11 support to full level. This means Nuitka is now expected to behave identical to CPython3.11 for the largest part.

There is plenty of new features in Nuitka, e.g. a new testing approach with reproducible compilation reports, support for including the metadata if an distribution, and more.

In terms of bug fixes, it’s also huge, and esp. macOS got a lot of improvements that solve issues with prominent packages in our dependency detection. And then for PySide we found a corruption issue, that got workarounds.

Bug Fixes

  • The new dict in optimization was compile time crashing on code where the dictionary shaped value checked for a key was actually an conditional expression

    # Was crashing
    "value" in some_dict if condition else other_dict

    Fixed in 1.5.1 already.

  • Standalone: Added support for openvino. This also required to make sure to keep used DLLs and their dependencies in the same folder. Before they were put on the top level. Fixed in 1.5.1 already.

  • Android: Convert RPATH to RUNPATH such that standalone binaries need no LD_LIBRARY_PATH guidance anymore. Fixed in 1.5.1 already.

  • Standalone: Added support for newer skimage. Fixed in 1.5.1 already.

  • Standalone: Fix, new data file type .json needed to be added to the list of extensions used for the Qt plugin bindings. Fixed in 1.5.2 already.

  • Standalone: Fix, the nuitka_types_patch module using during startup was released, which can have bad effects. Fixed in 1.5.2 already.

  • Android: More reliable detection of the Android based Python Flavor. Fixed in 1.5.2 already.

  • Standalone: Added data files for pytorch_lightning and lightning_fabric packages. Added in 1.5.2 already.

  • Windows: Fix, the preservation of PATH didn’t work on systems where this could lead to encoding issues due to reading a MBCS value and writing it as a unicode string. We now read and write the environment value as unicode both. Fixed in 1.5.3 already.

  • Plugins: Fix, the scons report values were not available in case of removed --remove-output deleting it before use. It is now read in case if will be used. Fixed in 1.5.3 already.

  • Python3.11: Added support for ExceptionGroup built-in type. Fixed in 1.5.4 already.

  • Anaconda: Fix, using numpy in a virtualenv and not from conda package was crashing. Fixed in 1.5.4 already.

  • Standalone: Added support for setuptools. Due to the anti-bloat work, we didn’t notice that if that was not sufficiently usable, the compiled result was not usable. Fixed in 1.5.4 already.

  • Distutils: Added support for pyproject with src folders. This supports now tool.setuptools.packages.find with a where value with pyproject files, where it typically is used like this:

    where = ["src"]
  • Windows: Fix, the nuitka-run batch file was not working. Fixed in 1.5.4 already.

  • Standalone: Add pymoo implicit dependencies. Fixed in 1.5.5 already.

  • macOS: Avoid deprecated API, this should fix newer Xcode being used. Fixed in 1.5.5 already.

  • Fix, the multiprocessing in spawn mode didn’t handle relative paths that become invalid after process start. Fixed in 1.5.5 already.

  • Fix, spec %CACHE_DIR% was not given the correct folder on non-Windows. Fixed in 1.5.5 already.

  • Fix, special float values like nan and inf didn’t properly generate code for C values. Fixed in 1.5.5 already.

  • Standalone: Add missing DLL for onnxruntime on Linux too. Fixed in 1.5.5 already.

  • UI: Fix, illegal python flags value could enable site mode. by mistake and were not caught. Fixed in 1.5.6 already.

  • Windows: Fix, user names with spaces failed with MinGW64 during linking. Fixed in 1.5.6 already.

  • Linux: Fix, was not excluding all libraries from glibc, which could cause crashes on newer systems. Fixed in 1.5.6 already.

  • Windows: Fix, could still pickup SxS libraries distributed by other software when found in PATH. Fixed in 1.5.6 already.

  • Windows: Fix, do not use cache DLL dependencies if one the files listed there went missing. Fixed in 1.5.6 already.

  • Onefile: Reject path spec that points to a system folder. We do not want to delete those when cleaning up clearly. Added in 1.5.6 already.

  • Plugins: Fix, the dill-compat was broken by code object changes. Fixed in 1.5.6 already.

  • Standalone: Added workaround for networkx decorator issues. Fixed in 1.5.7 already.

  • Standalone: Added workaround for PySide6 problem with disconnecting signals from methods. Fixed in 1.5.7 already.

  • Standalone: Added workaround for PySide2 problem with disconnecting signals.

  • Fix, need to make sure the yaml package is located absolutely or else case insensitive file systems can confuse things. Fixed in 1.5.7 already.

  • Standalone: Fix, extra scan paths were not considered in caching of module imports, breaking the feature in many cases. Fixed in 1.5.7 already.

  • Windows: Fix, avoid system installed appdirs package as it is frequently broken. Fixed in 1.5.7 already.

  • Standalone: The bytecode cache check needs to handle re-checking relative imports found in the cache better. Otherwise some standard library modules were always recompiled due to apparent import changes. Fixed in 1.5.7 already.

  • Nuitka-Python: Fix, do not insist on PYTHONHOME making it to os.environ in order to delete it again. Fixed in 1.5.7 already.

  • Nuitka-Python: Allow builtin modules of all names. This is of course what it does. Fixed in 1.5.7 already.

  • Nuitka-Python: Ignore empty extension module suffix. Was confusing Nuitka to consider every file an extension module potentially. Fixed in 1.5.7 already.

  • Plugins: Properly merge code coming from distinct plugins. The __future__ imports need to be moved to the start. Added in 1.5.7 already.

  • Standalone: Added support for opentele package. Fixed in 1.5.7 already.

  • Standalone: Added support for newer pandas and pyarrow usage. Fixed in 1.5.7 already.

  • Standalone: Added missing implicit dependency for PySide6. Fixed in 1.5.7 already.

  • Fix, the pyi-file parser didn’t handle doc strings, and could be crash for comment contents not conforming to be import statement code. Fixed in 1.5.8 already.

  • Standalone: Added support for pyqtlet2 data files.

  • Python2: Fix, PermissionError doesn’t exist on that version, which could lead to issues with retries for locked files e.g. but was also observed with symlinks.

  • Plugins: Recognize the error given by with upx if a file is already compressed.

  • Fix, so called “fixed” imports were not properly tracking their use, such that they then didn’t show up in reports, and didn’t cause dependencies on the module, which could e.g. impact importlib to not be included even if still being used.

  • Windows: Fix, retries for payload attachment were crashing when maximum number of retries were reached. Using the common code for retries solves that, since that code handles it just fine.

  • Standalone: Added support for the av module.

  • Distutils: Fix, should build from files in build folder rather than source files. This allows tools like versioneer that integrate with setuptools to do their thing, and get the result of that to compilation rather than the original source files.

  • Standalone: Added support for the Equation module.

  • Windows/macOS: Avoid problems with case insensitive file systems. The nuitka.Constants module and nuitka.constants package could collide, so we now avoid that package, there was only what is now nuitka.Serialization in there anyway. Also similar problem with nuitka.utils.Json and json standard library module.

  • Standalone: Added support transformers package.

  • Standalone: Fix for PyQt5 which needs a directory to exist.

  • macOS: Fix, was crashing with PyQt6 in standalone mode when trying to register plugins to non-default path. We now try to skip the need, which also makes it work.

  • Fix, recursion error for complex code that doesn’t happen in ast module, but during conversion of the node tree it gives to our own tree, were not handled, and crashed with RecursionError. This is now also handled, just like the error from ast.

  • Standalone: Added support for sqlfluff.

  • Standalone: Added support for PySide 6.5 on macOS solving DLL dependency issues.

  • Scons: Recognize more ccache outputs properly, their logging changed and provided irrelevant states, and ones not associated so far.

  • Onefile: Fix, could do random exit codes when failing to fork for whatever reason.

  • Standalone: Added support for pysnmp package.

  • Standalone: Added support for torchaudio and tensorflow on macOS. These contain broken DLL dependencies as relative paths, that are apparently ignored by macOS, so we do that too now.

  • Onefile: Use actual rather than guessed standalone binary name for multiprocessing spawns. Without this, a renamed onefile binary, didn’t work.

  • Fix, side effect nodes, that are typically created when an expression raises, were use in optimization contexts, where they do not work.

  • Standalone: Added missing implicit dependency for sentence_transformers package.

  • macOS: Fix, added missing dependency for platform module.

New Features

  • Support for Python 3.11 is finally there. This took very long, because there were way more core changes than with previous releases. Nuitka integrates close to that core, and is as such very affected by this. Also a lot of missed opportunities to improve 3.7 or higher, 3.9 or higher, and 3.10 or higher were implemented right away, as they were discovered on the way. Those had core changes not yet taken advantage of and as a result got faster with Nuitka too.

  • Reports: Added option --report-diffable to make the XML report created with --report become usable for comparison across different machine installations, users compiling, etc. so it can be used to compare versions of Nuitka and versions of packages being compiled for changes. Also avoid short names in reports, and resolve them back to long names, so they become more portable too.

  • Reports: Added option to provide custom data from the user. We use it in out testing to record the pipenv state used with things like --report-user-provided=pipenv-lock-hash=64a5e4 with this data ending up inside of reports, where tools like the new testing tool nuitka-watch can use it to decide if upstream packages changed or not. These are free form, just needs to fit XML rules.

  • Plugins: Added include-pyi-file flag to data-files section. If provided, the .pyi file belonging to a specific module is included. Some packages, e.g. skimage depend at runtime on them. For data file options and configuration, these files are excluded, but this is now the way to force their inclusion. Added in 1.5.1 already.

  • Compatibility: Added support for including distribution metadata with new option --include-distribution-metadata.

    This allows generic walks over distributions and their entry points to succeed, as well as version checks with the metadata packages that are not compile time optimized.

  • Distutils: Handle extension modules in build tasks. Also recognize if we built it ourselves, in which case we remove it for rebuild. Added in 1.5.7 already.

  • Linux: Detect DLL like filenames that are Python extension modules, and ignore them when listing DLLs of a package with --list-package-dlls option. So far, this was a manual task to figure out actual DLLs. This will of course improve the Yaml package configuration tooling .

  • Onefile: Allow forcing to use no compression for the onefile payload, useful for debugging, to avoid long compression times and for test coverage of the rare case of not compressing if the bootstrap handles that correctly too.

  • Need to resolve symlinks that were used to call the application binary in some places on macOS at least. We therefore implemented the previously experimental and Windows only feature for all platforms.

  • Standalone: Added support including symlinks on non-Windows in standalone distribution, if they still point to a path that is inside the distribution. This can save a bunch of disk space used for some packages that e.g. distribute DLL links on Linux.

  • Onefile: Added support for including symlinks from the standalone distribution as such on non-Windows. Previously they were resolved to complete copies.

  • UI: Respect code suffixes in package data patterns. With this e.g. --include-package-data=package_name:*.py is doing what you say, even if of course, that might not be working.

  • UI: Added option --edit-module-code option.

    To avoid manually locating code to open it in Visual Code replaced old find-module helper to be a main Nuitka option, where it is more accessible. This also goes beyond it it, such that it resolves standalone file paths to module names to make debugging easier, and that it opens the file right away.

  • Standalone: Added support for handling missing DLLs. Needed for macOS PySide6.5.0 from PyPI, which contains DLL references that are broken. With this feature, we can exclude DLLs that wouldn’t work anyway.


  • Anti-Bloat: Remove IPython usage in huggingface_hub package versions. Added in 1.5.2 already.

  • Anti-Bloat: Avoid IPython usage in tokenizers module. Added in 1.5.4 already.

  • Added support for module type as a constant value. We want to add all types we have shapes for to allow better type(x) optimization. This is only the start.

  • Onefile: During payload unpacking the memory mapped data was copied to an input buffer. Removing that avoids memory copying and reduces usage.

  • Onefile: Avoid repeated directory creations. Without it, the bootstrap was creating already existing directories up to the root over and over, making many unnecessary file system checks. Added in 1.5.5 already.

  • Anti-Bloat: Remove usage of IPython in trio package. Added in 1.5.6 already.

  • Onefile: Use resource for payload on Win32 rather than overlay. This integrates better with signatures, removing the need to check for original file size. Changed in 1.5.6 already.

  • Onefile: Avoid using zstd input buffer, but using the memory mapped contents directly avoiding to copy uncompressed payload data. Changed in 1.5.6 already.

  • Onefile: Avoid double slashes in expanded onefile temp spec paths, they are just ugly.

  • Anti-Bloat: Remove usage of pytest and IPython for some packages used by newer torch. Added in 1.5.7 already.

  • Anti-Bloat: Avoid triton to use setuptools. Added in 1.5.7 already.

  • Anti-Bloat: Avoid pytest in newer networkx package. Added in 1.5.7 already.

  • Prepare optimization for more built-in types with experimental code, but we need to disable it for now as it requires more completeness in code generation to cover them all. We did some, e.g. module type, but many more will be missing still.

  • Prepare optimization of class selection at compile time, by having a helper function rather than a dedicated node. This work is not complete though, and cannot be activated yet.

  • Windows: Cache short path name resolutions. Esp. for reporting, we now do a lot more of these than before, and this avoids they can become too time consuming.

  • Faster constant value handling for float value checks by avoiding module lookups per value.

  • Minimize size for hello world distribution such that no unused extension modules are included, by excluding even more modules and using modules from automatic inclusion of standard library.

  • Anti-Bloat: Catch pytest namespaces py and _pytest sooner, to point to the actual uses more directly.

  • Anti-Bloat: Usage of doctest equals usage of “unittest” so cover it too, to point to the actual uses more directly.

  • Ever more spelling fixes in code and tests were identified and fixed.

  • Make sure side effect nodes indicate properly that they are raising, allowing exceptions to fully bubble up. This should lead to more dead code being recognized as such.


  • GitHub: Added marketplace action designed to cross platform build with Nuitka on GitHub directly. Usable with both standard and commercial Nuitka versions, and pronouncing it as officially supported.

    Check out out at Nuitka-Action repository.

  • Windows: When MSVC doesn’t have WindowsSDK, just don’t use it, and proceed, to e.g. allow fallback to winlibs gcc.

  • User Manual: The code to update benchmark numbers as giving was actually wrong. Fixed in 1.5.1 already.

  • UI: Make it clear that partially supported versions are considered experimental, not unsupported. Fixed in 1.5.2 already.

  • Plugins: Do not list deprecated plugins with plugin-list, they do not have any effect, but listing them, makes people use them still. Fixed in 1.5.4 already.

  • Plugins: Make sure all plugins have descriptions. Some didn’t have any yet, and sometimes the wording was improved. Fixed in 1.5.4 already.

  • UI: Accept y as a shortcut for yes in prompts. Added in 1.5.5 already.

  • Reports: Make sure the DLL dependencies for Linux are in a stable order. Added in 1.5.6 already.

  • Plugins: Check for latest fixes in PySide6. Added in 1.5.6 already.

  • Windows XP: For Python3.4 make using Python2 scons work again, we cannot have 3.5 or higher there. Added in 1.5.6 already.

  • Quality: Updated to latest PyLint. With Python 3.11 the older one, was not really working, and it was about time. Due to its many changes, we included it in the hotfix, so those can still be done. Changed in 1.5.7 already.

  • Release: Avoid broken requires.txt in source distribution. This apparently breaks poetry. Changed in 1.5.7 already.

  • GitHub: Enhanced issue template for more clarity, esp. to avoid unnecessary options, e.g. using --onefile for issues that show up with --standalone already, to report factory branch issues rather on Discord, and give a quick tip for a likely reproducer if a package fails to import.

  • User Manual: Added instructions on how to add a DLL or executable to a standalone distribution.

  • User Manual: Example paths in the table for path specs, meant for Windows were not properly escaping the backslashes and therefore rendered incorrectly.

  • Visual Code: Python3.11 is now the default configuration for C code editing.

  • Developer Manual: Updated descriptions for adding test suite. While added the Python 3.11 test suite, these instructions were further improved.

  • Debugging: Make it easier to fully deactivate free lists. Now only need to set max size to 0 and the free list will not be used.

  • Debugging: Added more assertions, added corrections to feature disables, check args after function calls for validity, check more types to be as expected.

  • Plugins: Enhanced plugin error messages generally, with --debug exceptions become warning messages with the original exception being raised instead, making debugging during development much easier.

  • UI: Make it clear what not using ccache actually means. Not everybody is familiar with the design of Nuitka there or what the tool can actually do.

  • UI: Do not warn about not found distributions but merely inform of them.

    Since Nuitka is fully compatible with these, no need to consider those a warning, for some packages they also are given really a lot.

  • UI: Catch user error of wrong cases plugin names

    This now points out the proper name rather than denying the existence outright. We do not want to accept wrong case names silently.


  • Use proper API for setting PyConfig values during interpreter initialization. There is otherwise always the risk of crashes, should these values change during runtime. Fixed in 1.5.2 already.

  • For our reformulations have a helper function that build release statements for multiple variables at once. This removed a bunch of repetitve code from re-formulations.

  • Move the pyi-file parser code out of the module nodes and to source handling, where it is more closely related.


  • Adding a nuitka-watch tool, which is still experimental and for use with the Nuitka-Watch repository.

  • Refined macOS standalone exceptions further to cover more normal usages of files on that OS and for frameworks that applications typically use from the system.

  • Detect and consider onefile mode if given in project options as well.

  • Was not really applying import check in programs tests. Added in 1.5.6 already.

  • Added coverage of testing the signing of Windows binaries with the commercial plugin.

  • Added coverage of version information to hello world onefile test, so we can use it for Virus tools checks.

  • Added tests to cover PyQt6 and PySide6 plugin availability, we so far only had that for PyQt5, which is of course not relevant, and totally different code anyway.

  • Cleanup distutils tests case to use common test case scanning. We now decide version skips based on names, and had to get away from number suffixes, so they are now in the middle.


The class bodies optimization has made some progress in this release, going to a re-formulation of the metaclass selection, so as to allow its future optimization. We are not yet at “compiled objects”, but this is a promising road. We need to make some optimization improvements for inlining constant value calls, then this can become really important, but by itself these changes do not yield a lot of improvement.

For macOS again a bunch of time was spent to improve and complete the detection of DLL dependencies. More corner cases are covered now and more packages just work fine as a result.

The most important is to become Python3.11 compatible, even if attribute lookups, and other things, and not yet optimized. We will get to that in future releases. For now, compatibility is the first step to take.

For GitHub users, the Nuitka-Action will be interesting. But it’s still in develop. We keep adding missing options of Nuitka for a while it seems, but for most people it should be usable already.

The new nuitka-watch ability, should allow us to detect breaking PyPI releases, that need a new tweak in Nuitka sooner. But it will probably grow in the coming releases to full value only. For now the tool itself is not yet finished.

From here, a few open ends in the CPython 3.11 test suite will have to be addressed, and maybe some of the performance tricks that it now will enable, e.g. with repeated attribute lookups.

Nuitka Release 1.5

This release contains the long awaited 3.11 support, even if only on an experimental level. This means where 3.10 code is used, it is expected to work equally well, but the Python 3.11 specific new features have yet been done.

There is plenty of new features in Nuitka, e.g. much enhanced reports, Windows ARM native compilation support, and the usual slew of anti-bloat updates, and newly supported packages.

Bug Fixes

  • Standalone: Added implicit dependencies for charset_normalizer package. Fixed in 1.4.1 already.

  • Standalone: Added platform DLLs for sounddevice package. Fixed in 1.4.1 already.

  • Plugins: The info from Qt bindings about other Qt bindings being suppressed for import, was spawning multiple lines, breaking tests. Merged to a single line until we do text wrap for info messages as well. Fixed in 1.4.1 already.

  • Plugins: Fix removeDllDependencies was broken and could not longer be used to remove DLLs from inclusion. Fixed in 1.4.1 already.

  • Fix, assigning methods of lists and calling them that way could crash at runtime. The same was true of dict methods, but had never been observed. Fixed in 1.4.2 already.

  • Standalone: Added DLL dependencies for onnxruntime. Fixed in 1.4.2 already.

  • Standalone: Added implicit dependencies for textual package. Fixed in 1.4.2 already.

  • Fix, boolean tests of lists could be optimized to wrong result when list methods got recognized, due to not annotating the escape during that pass properly. Fixed in 1.4.3 already.

  • Standalone: Added missing implicit dependency of apsw. Fixed in 1.4.3 already.


    Currently apsw only works with manual workarounds and only in limited ways, there is an import level incompatible with __init__ being an extension module, that Nuitka does not yet handle.

  • Python3: Fix, for range arguments that fail to divide there difference, the code would have crashed. Fixed in 1.4.3 already.

  • Standalone: Fix, added support for newer pkg_resources with another vendored package. Fixed in 1.4.4 already.

  • Standalone: Fix, added support for newer shapely 2.0 versions. Fixed in 1.4.4 already.

  • Plugins: Fix, some yaml package configurations with DLLs by code didn’t work anymore, notably old shapely 1.7.x versions were affected. Fixed in 1.4.4 already.

  • Fix, for onefile final result the “–output-dir” option was ignored. Fixed in 1.4.4 already.

  • Standalone: Added mozilla-ca package data file. Fixed in 1.4.4 already.

  • Standalone: Fix, added missing implicit dependency for newer gevent. Fixed in 1.4.4 already.

  • Scons: Accept an installed Python 3.11 for Scons execution as well. Fixed in 1.4.4 already.

  • Python3.7: Some importlib.resource nodes asserted against use in 3.7, expecting it to be 3.8 or higher, but this interface is present in 3.7 already. Fixed in 1.4.5 already.

  • Standalone: Fix, Python DLLs installed to the Windows system folder were not included, causing the result to be not portable. Fixed in 1.4.5 already.

  • Python3.9+: Fix, metadata.resources files method joinpath is some contexts is expected to accept variable number of arguments. Fixed in 1.4.5 already.

  • Standalone: Workaround for customtkinter data files on non-Windows. Fixed in 1.4.5 already.

  • Standalone: Added support for overrides package. Fixed in 1.4.6 already.

  • Standalone: Added data files for strawberry package. Fixed in 1.4.7 already.

  • Fix, anti-bloat plugin caused crashes when attempting to warn about packages coming from --include-package by the user. Fixed in 1.4.7 already.

  • Windows: Fix, main program filenames with an extra dot apart from the .py suffix, had the part beyond that wrongly trimmed. Fixed in 1.4.7 already.

  • Fix, list methods didn’t properly annotated value escape during their optimization, which could lead to wrong optimization for boolean tests. Fixed in 1.4.7 already.

  • Standalone: Added support for imagej, scyjava, jpype packages. Fixed in 1.4.8 already.

  • Fix, using --include-package on extension module names was not working. Fixed in 1.4.8 already.

  • Standalone: Added support for tensorflow.keras namespace as well.

  • Distutils: Fix namespace packages were not including their contained modules properly with regards to __file__ properties, making relative file access impossible.

  • Onefile: On Windows the onefile binary did lock itself, which could fail with certain types of AV software. This is now avoided.

  • Accessing files using the top level metadata.resources files object was not working properly, this is now supported too.

  • MSYS2: Make sure mixing POSIX and Windows slashes causes no issues by hard-coding the onefile archive to use the subsystem slash rather than what MSYS prefers to use internally.

  • Standalone: Added missing dependencies of newer imageio.

  • Fix, side effect nodes didn’t annotate their non-exception raising nature properly, if that was the case.

New Features

  • Added experimental support for Python 3.11, for 3.10 language level code it should be fully usable, but the CPython311 test suite has not even been started to check newly added or changed features.

  • Windows: Support for native Python on Windows ARM64, which needs 3.11 or higher, but standalone and therefore onefile do not yet work, due to lack of any form of binary dependency analysis tool.

    This platform is relatively new in Python and generally. For the time being standalone and onefile should be done with Intel based Python, they would also be ARM64 only, whereas 32/64 Bit binaries can be run on all Windows ARM platforms.

  • Reports: Write compilation report even in case of Nuitka being interrupted or crashing. This then includes the exception, and a status like completed or interrupted. At this time this happens only when --report= was specified, but in the future we will likely write one in case of Nuitka crashes.

  • Reports: Now the details of the used Python version, its flavor, the OS and the architecture are included. This is crucial information for analysis and can make --version output unnecessary.

  • Reports: License reports now handle UNKNOWN license by falling back to checking the classifiers, and therefore include the correct license e.g. with setuptools. Also in case no license text is found, do not create an empty block. Added in 1.4.4 already.

  • Reports: In case the distribution name and the contained package names differ, output the list of packages included from a distribution. Added in 1.4.4 already.

  • Reports: Include data file sizes in report. Added in 1.4.7 already.

  • Reports: Include memory usage into the compilation report as well.

  • macOS: Add support for downloading ccache on arm64 (M1/M2) too. Added in 1.4.4 already.

  • UI: Allow --output-filename for standalone mode again. Added in 1.4.3 already.

  • Standalone: Improved isolation with Python 3.8 or higher. Using new init mechanisms of Python, we now achieve that the scan for pyvenv.cfg on in current directory and above is not done, using it will be unwanted.

  • Python2: Expose __loader__ for modules and register with pkg_resources too which expects these to be present for custom resource handling.

  • Python3.9+: The metadata.resources files objects method iterdir was not implemented yet. Fixed in 1.4.5 already.

  • Python3.9+: The metadata.resources files objects method absolute was not implemented yet.

  • Added experimental ability to create virtualenv from an existing compilation report with new --create-environment-from-report option. It attempts to create a requirements file with the used packages and their versions. However, sometimes it seems not to be possible to due to conflicts.


  • Onefile: Use memory mapping for calculating the checksum of files on all platforms. This is faster and simpler code. So far it had only be done this way on Windows, but other platforms also benefit a lot from it.

  • Onefile: Use memory mapping for accessing the payload rather than file operations. This avoids differences to macOS payload handling and is much faster too.

  • Anti-Bloat: Avoid using dask in joblib.


    Newer versions of joblib do not currently work yet due to their own form of multiprocessing spawn not being supported yet.

  • Anti-Bloat: Adapt for newer pandas package.

  • Anti-Bloat: Remove more IPython usages in newer tensorflow.

  • Use dedicated class bodies for Python2 and Python3, with the former has a static dict type shape, and with Python3 this needs to be traced in order to tell what the meta class put in there.

  • Compile time optimize dict in/not in and dict.has_key operations statically where the keys of a dict are known. As a result, the class declarations of Python3 no longer created code for both branches, the one with metaclass = in the class declaration and without. That means also a big scalability improvement.

  • For the Python3 class bodies, the usage of locals() was not recognized as not locally escaping all the variables, leading to variable traces where each class variable was marked as escaped for no good reason.

  • Added support for dict.fromkeys method, making the code generation understand and handle static methods as well.

  • Added support for os.listdir and os.path.basename. Added in 1.4.5 already for use in implementing the iterdir method, but they are also now optimized by themselves.

  • Added support for trusted constant values of the os module. These are curdir, pardir, sep, extsep, altsep, pathsep, linesep which may enable some minor compile time optimization to happen and completes this aspect of the os module.

  • Faster digit size checks during float code generation for better compile time performance.

  • Faster list operations due to using PyList_CheckExact everywhere this is applicable, this mostly makes debug operations faster, but also deep copying list values, or extending lists with iterables, etc.

  • Optimization: Collect module usages of the given module during its abstract execution. This avoids a full tree visit afterwards only to find them. It is much cheaper to collect them while we go over the tree. This enhances the scalability of large compilations by ca. 5%.

  • Optimization: Faster determination of loop variables. Rather than using a generic visitor, we use the children having generator codes to add traversal code that emits relevant variables to the user directly.

  • Cache extra search paths in order to avoid repeated directory operations as these are known to be slow at times.

  • Standalone: Do not include py.typed data files, these indicator files are for IDEs, but not needed at run time ever.

  • Make sure that the generic attribute code optimization is also effective in cases where a Python DLL is used. Previously this was only guaranteed to be used with static libpython.

  • Faster list constant usage

    Small immutable constants get their own code that is much faster for small sizes.

    Medium sized lists get code that just is hinted the size, but takes items from a source list, still a lot faster.

    For repeated lists where all elements are the same, we use a dedicated helper for all sizes, that is even faster except for small ones with LTO enabled, where the C compiler may already do that effectively.

  • Added optimization for os.path.abspath and os.path.isabs which of course have not as much potential for compile time optimization, but we needed them for providing .absolute() for the meta path loader files implementation.

  • Faster class dictionary propagation decision. Instead of checking for trace types, let the trace object decide. Also abort immediately on first inhibit, rather than checking all variables. This improves Python2 compile time, and Python3 where this code is now starting to get used when the class dictionary is shown to have dict type.

  • Specialize type method __prepare__ which is used in the Python3 re-formation of class bodies to initialize the class dictionary. Where the metaclass is resolved, we can use this to decide that the standard empty dictionary is used statically, enabling class dictionary propagation for best scalability.

    At this time this only happens with classes without bases, but we expect to soon do this with all compile time known base classes. At this time, these optimization to become effective, we need to optimize meta class selection from bases classes, as well as modification of base classes with __mro_entries__ methods.

  • The bool built-in on boolean values is now optimized away.

    Since it’s used also for conditions being extracted, this is actually somewhat relevant, since it could keep code alive in side effects at least for no good reason and this allows a proper reduction.


  • Project: Require the useful stuff for installation of Nuitka already. These are things we cannot inline really, but otherwise will frequently be warned about, e.g. zstandard for onefile and ordered-set for fast operation, but we do not require packages that might fail to install.

  • User Manual: Added section about virus scanners and how to avoid false reports.

  • User Manual: Enhanced description for plugin module loading, the old code was too complicated and actually working only for a mode of including plugin code that is discouraged.

  • User Manual: Fix section for standalone finding files on wrong level.

  • Windows: Using the console on Python 3.4 to 3.7 is not working very well with e.g. many Asian systems. Nuitka fails to setup the encoding for stdin and stdout or this platform. It can then produce exceptions on input or output of unicode data, that doesn’t overlap with UTF-8.

    We now inform the user of these older Python with a warning and mnemonic, to either disable the console or to upgrade to Python 3.8 or higher, which normally won’t be much of an issue for most users.

    Read more on the info page for detailed information. Added in 1.4.1 already.

  • Debugging: Fixup debugging reference count output with Python3.4. For Python 3.11 compatibility tests, actually it was useful to compare with a version that doesn’t have coroutines yet. Never tell me, supporting old versions is not good.

  • Deprecating support for Python 3.3, there is no apparent use of this version, and it has gained specific bugs, that are indeed not worth our time. Python 2.6 and Python 2.7 will continue to be supported probably indefinitely.

  • Recommend ordered-set for Python 3.7 to 3.9 as well, as not only for 3.10+ because on Windows, to install orderset MSVC needs to be installed, whereas ordered-set has a wheel for ready use.

  • Actually zstandard requirement is for a minimal version, added that to the requirement files.

  • Debugging: Lets not reexecute Nuitka in case if we are debugging it from Visual Code.

  • Debugging: Include the .pdb files in Windows standalone mode for proper C tracebacks should that be necessary.

  • UI: Detect the GitHub flavor of Python as well.

  • Quality: Check the clang-format version to avoid older ones with bugs that made it switch whitespace for one file. Using the one from Visual Code C extension is a good idea, since it will often be available. Running the checks on newer Ubuntu GitHub Actions runner to have the correct version available.

  • Quality: Updated the version of rstfmt and isort to the latest versions.

  • GitHub: Added commented out section for enabling ssh login, which we occasionally need to git bisect problems specific to GitHub Python flavor.

  • Plugins: Report problematic plugin name with module name or DLL name when these raise exceptions.

  • Use ordered-set package for Python3.7+ rather than only Python3.10+ because it doesn’t need any build dependency on Windows.

  • UI: When showing source changes, also display the module name with the changed code.

  • UI: Use function intended for user query when asking about downloads too.

  • UI: Do not report usage of ccache for linking from newer version, that is not relevant.

  • Onefile: Make sure we have proper error codes when reporting IO errors.

  • MSVC: Detect a version for developer prompts too. This version is needed for use in enabling version specific features.

  • Started UML diagrams with plantuml that will need to be completed before using them in then new and more visual parts of Nuitka documentation.

  • UI: Check icon conversion capability at start of compilation rather than error exiting at the very end informing the user about required imageio packages to convert to native icons.

  • Quality: Enhanced autoformat on Windows, which was susceptible to tools introducing Windows new lines before other steps were performed, that then could be confused, also enforcing use of UTF-8 encoding when working with Nuitka source code for formatting.


  • The delvewheel plugin was still using a zmq class name from its original implementation, adapted that.

  • Use common template for generator frames as well. This made them also work with 3.11, by avoiding duplication.

  • Applied code formatting to many more files in tests, etc.

  • Removed a few micro benchmarks that are instead to be covered by construct based tests now.

  • Enhanced code generation for specialized in-place operations to avoid unused code for operations that do not have any shortcuts where the operation would be actual in-place of a reference count 1 object.

  • Better code generation for module variable in-place operations with proper indentation and no repeated calls.

  • Plugins: Use the namedtuple factory that we created for informational tuples from plugins as well.

  • Make details of download utils module more accessible for better reuse.

  • Remove last remaining Python 3.2 version check in C code, for us this is just Python3 with 3.2 being unsupported.

  • Cleanup, name generated call helper file properly, indicating that it is a generated file.


  • Made the CPython3.10 test suite largely executable with Python 3.11 and running that with CI now.

  • Allow measuring constructs without writing the code diff again. Was crashing when no filename was given.

  • Make Python3.11 test execution recognized by generally accepting partially supported versions to execute the tests with.

  • Handle also newfstat directory checks in file usage scan. This are used on newer Linux systems.

  • GitHub: In actions use --report for coverage and upload the reports as artifacts.

  • Use no-qt plugin to avoid warnings in matplotlib test rather than disabling the warnings about Qt bindings.

  • macOS: Detect if the machine can take runtime traces, which on Apple Silicon by default it cannot.

  • macOS: Cover all APIs for file tracing, rather than just one for extended coverage.

  • Fix, distutils test was not installing the built wheels, but source archive and therefore compiling that second time.

  • For the pyproject.toml using tests, Nuitka was always downloaded from PyPI rather than using the version under test.

  • Ignore ld info output about mismatching architecture libraries being ignored. Fixed in 1.4.1 already.


With this release an important new avenue for scalability has been started. While for Python2 class bodies were very often reduced to just that dictionary creation, with Python3 that was not the case, due to the many new complexities, and while this release makes a start, we will be able to continue this path towards much more scalable class creation codes. And while the performance does not really matter all that much for these, knowing these, will ultimately lead us to “compiled classes” as our own type, and “compiled objects” that may well perform much faster.

Already now, the enhancements to class creation codes will result in smaller binaries, but much more is expected the more this is completed.

The majority of the work was of course to become Python3.11 compatible, and unfortunately the attribute lookups are not as optimized as for 3.10 yet, which may cause disappointing results for performance initially. We will need to complete that before benchmarks will make much sense.

For the next release, full Python 3.11 support is planned. I believe it should be usable. Problems with 3.11 may get hotfixes, but ultimately the develop version is probably the one to recommend when using 3.11 with Nuitka, as there will be the whole set of fixes, since not everything will be ported back.

The new reports should be used in bug reporting soon. We foresee that for issue reports, these may well become mandatory. Together with the ability to create a virtualenv from the reports, this may make reproducing issues a breeze, but first tries on complex projects were also highlighting that it may not be as simple.

Nuitka Release 1.4

This release contains a large amount of performance work, where specifically Python versions 3.7 or higher see regressions in relative performance to CPython fixed. Many cases of macros turned to functions have been found and resolved. For 3.10 specifically we take advantage of new opportunities for optimization. And generally avoiding DLL calls will benefit execution times on platform where the Python DLL is used, most prominently Windows.

Then this also adds new features, specifically custom reports. Also tools to aid with adding Nuitka package configuration input data, to list DLLs and data files.

With multidist we see a brand new ability to combine several programs into one, that will become very useful for packaging multiple binaries without the overhead of multiple distributions.

Bug Fixes

  • Standalone: Added implicit dependencies for dependency_injector package. Fixed in 1.3.1 already.

  • Fix, the generated metadata nodes for distribution queries had an error in their generated children handling that could cause crashes at compile time. Fixed in 1.3.2 already.

  • Standalone: Added implicit dependencies for passlib.apache package. Fixed in 1.3.2 already.

  • Windows: Fix, our shortcut to find DLLs by analyzing loaded DLLs stumbled in a case of a DLL loaded into the compiling Python that had no filename associated, while strange, we need to handle this as well. Fixed in 1.3.3 already.

  • Standalone: Also need to workaround more decorator tricks for networkx. Fixed in 1.3.3 already.

  • Scons: Fix, was not updating PATH environment variable anymore, which could lead to externally provided compilers and internal winlibs gcc clashing on Windows, but should be a general problem. Fixed in 1.3.4 already.

  • Standalone: Added support for cefpython3 package. Fixed in 1.3.4 already.

  • Standalone: Added support for newer webview package versions. Fixed in 1.3.4 already.

  • Standalone: Fix, some extension modules set their __file__ to None during multi phase imports, which we then didn’t update anymore, however that is necessary. Fixed in 1.3.4 already.

  • Python3.10+: Fix, was not supporting match cases where an alternative had no condition associated. Fixed in 1.3.5 already.

  • Windows: Identify Windows ARM architecture Python properly. We do not yet support it, but we should report it properly and some package configurations are already taking it already into account. Fixed in 1.3.5 already.

  • Fix, the Nuitka meta path based loader, needs to expose a __module__ attribute because there is code out there, that identifies standard loaders through looking at this value, but crashes without it. Fixed in 1.3.5 already.

  • Fix, very old versions of the importlib_metadata backport were using themselves to load their __version__ attribute. Added a workaround for it, since in Nuitka it doesn’t work until after loading the module.

  • Fix, value escapes for attribute and subscript assignments sources were not properly annotated. This could cause incorrect code execution. Fixed in 1.3.6 already.

  • Fix, “pure” functions, which are currently only our complex call helper functions, were not visited in all cases. This lead to a crash in code generation after modules using them got demoted to bytecode. After use from cache, this didn’t happen again. Fixed in 1.3.6 already.

  • Standalone: Added more implicit dependencies of crypto packages. Fixed in 1.3.6 already.

  • Standalone: Added implicit dependencies of pygments.styles module. Fixed in 1.3.6 already.

  • Fix, was falsely encoding Ellipsis too soon during tree building. It is not quite like True and False. Fixed in 1.3.6 already.

  • Standalone: Fix, numpy on macOS didn’t work inside an application bundle anymore. Fixed in 1.3.7 already.

  • Python3.8+: Fix, need to follow change for extension module handling, otherwise some uses of os.add_dll_directory fail to work. Fixed in 1.3.8 already.

  • Standalone: Added missing implicit dependencies of sqlalchemy. Fixed in 1.3.8 already.

  • Python3.9+: Fix, resource reader files was not fully compatible and needed to register with importlib.resources.as_file to work well with it. Fixed in 1.3.8 already.

  • Fix, the version check for cv2 was not working with the opencv-python-headless variant. Package name and distribution name is not a 1:1 mapping for all things. Fixed in 1.3.8 already.

  • Standalone: Added DLLs needed for tls_client package.

  • Fix, imports of resolved names should be modified for runtime too. Where Nuitka recognizes aliases, as e.g. the requests module does, it only adding a dependency on the resolved name, but not requests itself. The import however was still done at runtime on requests which then didn’t work. This was only visible if only these aliases to other modules were used.

  • Onefile: Fix, do not send duplicate CTRL-C to child process. Our test only send it to the bootstrap process, rather than the process group, as it normally is working, therefore misleading us into sending it to the child even if not needed.

  • Onefile: When not using cached mode, on Windows the temporary folder used sometimes failed to delete after the executable stopped with CTRL-C. This is due to races in releasing of locks and process termination and AV tools, so we now retry for some time, to make sure it is always deleted.

  • Standalone: Fix, was not ignoring .dylib when scanning for data files unlike all other DLL suffixes.

  • Standalone: Added missing implicit dependency of mplcairo.

  • Standalone: The main binary name on non-Windows didn’t have a suffix .bin unlike in accelerated mode. However, this didn’t work well for packages which have binaries colliding with the package name. Therefore now the suffix is added in this case too.

  • macOS: Workaround bug in platform_utils.paths. It is guessing the wrong path for included data files with Nuitka.

  • Standalone: Added DLLs of sound_lib, selecting by OS and architecture.

  • Fix, for package metadata as from importlib.metadata.metadata for use at runtime we need to use both package name and distribution name to create it, or else it failed to work. Packages like opencv-python-headless can now with this too.

  • Standalone: Added support for tkinterweb on Windows. Other platforms will need work to be done later.

New Features

  • UI: Added new option to listing package data files. This is for use with analyzing standalone issues. And will output all files that are data files for a given package name.

    python -m nuitka --list-package-data=tkinterweb
  • UI: Added new option to listing package DLL files. This is also for use with analyzing standalone issues.

    python -m nuitka --list-package-dlls=tkinterweb
  • Reports: The usages of modules, successful or not, are now included in the compilation report. Checking out which ones are not-found might help recognition of issues.

  • Multidist: You can now experimentally create binaries with multiple entry points. At runtime one of multiple __main__ will be executed. The option to use is multiple arguments. If then the binary name is changed, on execution you get a different variant being executed.


    Using it with only one replaces the previous use of the positional argument given and is not using multidist at all.


    Multidist is compatible with onefile, standalone, and mere acceleration. It cannot be used for module mode obviously.

    For deployment this can solve duplication.


    For wheels, we will probably change those with multiple entry points to compiling multidist executables, so we do avoid Python script entry points there. But this has not yet been done.

  • Onefile: Kill non-cooperating child processes on CTRL-C after a grace period, that can be controlled at compile time with --onefile-child-grace-time the hard way. This avoids hangs of processes that fail to properly shutdown.

  • Plugins: Add support for extra global search paths to mimic sys.path manipulations in the Yaml configuration with new global-sys-path import hack.

  • Reports: Include used distributions of compiled packages and their versions.

  • Reports: Added ability to generate custom reports with --report-template where the user can provide a Jinja2 template to make his own reports.

  • Anti-Bloat: Added support for checking python flags. There are no_asserts, no_docstrings and no_annotations now. These can be used to limit rules to be only applied when these optional modes are active.

    Not all packages will work in these modes, but often can be enhanced to work with relatively little patching. This allows to limit these patches to only where they are necessary.


  • Anti-Bloat: Avoid using sparse and through that Numba in the scipy package, reducing its distribution footprint. Part of 1.3.3 already.

  • Anti-Bloat: Avoid IPython and Numba in trimesh package. Part of 1.3.3 already.

  • Anti-Bloat: Avoid Numba in shap package. Part of 1.3.8 already.

  • Anti-bloat: Removed xgboost docstring dependencies, such that --python-flag=no_docstrings can be used with this package.

  • For guided deep copy frozenset and empty tuple need no copies

    This also speeds up copies of non-empty tuples by avoiding that size checking branch in construction with Python 3.10 or higher.

  • For node construction, avoid keyword argument style calls of the base class, where there is only a single argument. They don’t really help readability, but cost compile time.

  • Determine guard mode of frames dynamically and avoid frame preservation checks where they are not needed.

    For Python2 this is necessary, but not for Python3, so make the function avoid finding the parent frame for that version entirely, which should speed up compilation as well.

    By not hard coding frame guard mode at creation time, and instead determine it at compile time, after optimization, so this now allows to use the “once” mode more often. This affects contractions and also classes on the module level right now. They do not need a cached frame, since their code is only executed once.

    By avoiding that useless code, the C compiler also has a slightly better scalability, since the classes are all created in one function that then has less code.

  • The bytecode cache is now checking if the used modules or attempted to be used modules are available or not in just the same way. Previously it was very dependent on the file system to contain the same things, which was not giving cache hits even after only creating a new folder near a binary, since that affected importable modules. With the new check it should be much more directly hitting even across different virtual environments, but with same code.

  • Generate base classes or mixins for all kinds of expression, statements and statement sequences. The previous code had a dedicated variant for single child, to allow faster operation in a common case, but still a lot of hasattr/getattr/setattr on dynamic attribute names were done. This was making the tree traversal during optimization slower than necessary.

    Another shortcoming was that for some nodes, some values are optional, where for others, they are not. Some values are a tuple actually, while most are nodes only. However, dealing with this generically was also slower than necessary.

    The new code now enforces children types during creation and updated, it rejects unexpected None values for non-optional children, and it provides generated code to do this in the fastest way possible, although surely some more improvements will come here.

    Also when abstract executing the tree, rather than generically visiting all children, this now just unrolls this, and there are even some modes added, where a node can indicate properties, e.g. auto_compute_handling = "final,no_raise" will tell the code generator that this expression never raises in the computation, and is final, i.e. doesn’t have any code to evaluate, because it cannot be optimized any further.

    Also the way checkers previously worked, for every node creation, for every child update, a dictionary lookup had to be done. This is now hard coded for the few nodes that actually want to convert values on the fly and we might make a difference in the future for optional checkers, such that these are only run in debug mode.

    These changes brought about much faster compilation, however the big elephant in the room will still be merging value traces, and scalability problems remain there.

  • Attribute node generation for method specs like dict.update, etc. now provide type shapes. From these type shapes, mixins for the result value type are picked automatically. Previously these shapes were added manually. In some cases, they were even missing. In a few cases, where the type is dependent on the Python version, we do not currently do this though, so this needs more work, but expanding the coverage got easier in this way.

  • Determining the used modules of a module requires a tree visit operations, that then asked for node types and used different APIs. This has been unified to be able to call a virtual method instead, which saves some compile time.

  • After scanning for a module, we then determined the module kind even after we previously knew it during the scan. Also, this was checking os.path.isdir which was making it relatively slow and wasting 5% compile time on the IO being done. The check got enhanced and most often replaced with using the knowledge from the original import scan eliminating this time.

  • Already most helper code of Nuitka was included from .c files, but compiled generators and compiled cells codes were not yet done like this, making life unnecessarily harder for the compiler and linker. This should also allow more optimization for some codes.

  • Cache the plugin decisions about recursion for a module name. When a module is imported multiple times plugins were each asked again and again, which is not a good thing to do.

  • Avoid usage of PyObject_RichCompareBool API, as we have our own comparison functions that are faster and faster to call without crossing of DLL barrier.

  • Python3.8+: Avoid usage of PyIndex_Check which has become an API in 3.8, and was as a result not inlined anymore with a DLL barrier was to be crossed, making all kinds of multiplication and subscript/index operations slower.

  • Replace PyNumber_Index API with our own code. As of 3.10 it enforces a conversion to long that for Nuitka is not a good thing to do in all places. But also due to DLL barrier it was potentially slow to call, and is used a lot, and we can drop the checks that are useless for Nuitka.

  • Python3.7+: Avoid the use of PyImport_GetModule for looking up imported modules from sys.modules, rather look it up from interpreter internals, also this was using subscript functions, when this is always a dictionary.

  • Avoid using PyImport_GetModuleDict and instead have our own API to get this quicker.

  • Faster exception match checks and sub type checks.

    This solves a TODO about inlining the API function used, so we can be faster in a relatively common operation. For every exception handler, we had to do one API call there.

  • Faster subtype checks.

    These are common in binary operations on non-identical types, but also needed for the exception checks, and object creation through class type calls. With our own PyType_IsSubType replacement these faster to use and avoid the API call.

  • Faster Python3 int value startup initialization.

    On Python 3.9 or higher we can get small int values directly from the interpreter, and with 3.11 they are accessible as global values.

    Also we no longer de-duplicate small int values through our cache, since there is no use in this, saving a bunch of startup time. And we can create the values with our own API replacement, that will work during startup already and save API calls as these can be relatively slow. And esp. for the small values, this benefits from not having to create them.

  • Faster Python3 bytes value startup initialization.

    On Python 3.10 or higher, we can create these values ourselves without an API call, avoiding its overhead.

    Also we no longer de-duplicate small bytes values through our cache, because that is already done by the API and our replacement, so this was just wasting time.

  • Faster slice object values with Python 3.10 or higher

    On Python 3.10 or higher, we can create these values ourselves without an API call, avoiding its overhead.

    These are important for Python3, because a[x:y] in the general case has to use a[slice(x,y)] on that version, making this somewhat relevant to performance in some cases.

  • Faster str built-in with API calls

    For common cases, this avoids API calls. We mostly have this such that print style tests do not have this as API calls where we strive to remove all API calls for given programs.

  • Faster exception normalization.

    For the common case, we have our own variant of PyErr_NormalizeException that will avoid the API call. It may still call the PyObject_IsSubclass API, for which we only have started replacement work, but this is already a step ahead in the right direction.

  • Faster object releases

    For Python3.8 or higher when our code released objects, it was doing that with an API call, due to a macro change in Python headers. We revert that and do it still on our own which avoids the performance penalty.

  • Enable Python threading during extension module DLL loading

    We now release the GIL for Python3.8 or higher when loading the DLL, following a change in that version.

  • Faster variable handling in trace collection. The code was doing checks for variable types, to decide what to do e.g. when control flow escapes for a variable. However, this is faster if solved with a virtual method in those variable classes, shifting the responsibility to inside there.

  • For call codes the need to check the return value was not perfectly annotated in all cases. This is now driven by the expression rather than passed, and will result in better code generated in some corner cases.


  • Release: Make clear we require wheel and setuptools to install by adding a pyproject.toml that addresses a warning of pip. Part of 1.3.6 release already.

  • Debugging: When plugins evaluate when conditions that raise, output which it was exactly. Part of 1.3.3 already.

  • Anti-Bloat: Added a mnemonic and more clear message for the case of unwanted imports being encountered. Also do not warn about IPython itself using IPython packages, that must of course be considered normal. Now it also lists the module that does the unwanted usage immediately. Previously this was not as clear.

  • UI: More clear output for not yet supported Python version. Make it more clear in the message, what is the highest supported version, and what version is Nuitka and what is Python in this.

  • UI: Make sure data files have normalized paths. Specifically on Windows, otherwise a mix of slashes could appear. Part of 1.3.6 release already.

  • UI: Make it clear that disabling the console harms your debugging when we suggest the --disable-console for GUI packages. Otherwise using that, they just deprive themselves of ways to get error information.

  • UI: The ordering of scons ccache report was not enforced. Part of 1.3.7 release already.

  • Quality: Use proper temporary filename during autoformat, so as to avoid flicker in Visual Code, e.g. search results.

  • User Manual: Was still using old option name for --onefile-tempdir-spec that has since been made not OS specific, with even the OS specific name being removed.

  • Standalone: Do not include data files scanned with site-packages or __pycache__ folders. This should make it easier to use --include-data-file=./**.qml:. when you have a virtualenv living in the same folder.

  • Onefile: Added check for compression ability before starting the compilation to inform the user immediately.

  • Release: Mark macOS as supported in PyPI categories. This is of course true for a long time already.

  • Release: Mark Android as supported in PyPI categories as well. With some extra work, it can be used.

  • User Manual: Added section pointing to and explaining compilation reports. This has become extremely useful even if still somewhat work in progress.

  • User Manual: Added table with included custom reports, at this time only the license reports, which is very rough shape and needs contributors for good looks and content.


  • Plugins: Moved parts of the pywebview plugin that pertain to the DLLs and data files to package configuration.

  • Made the user query code a dedicated function, so it can be reused and more consistent across its uses in Nuitka. With a default that is proposed to a user, and a default that applies if used non-interactively. We will switch all prompts to using this.

  • Code generation for module, class and function frames is now unified, removing duplication while also becoming more flexible. For generators this work has been started, but is not yet completed.

  • Nodes exposing used modules now implement the same virtual method providing a list of them.

  • Make sure to pass tuple values rather than list values from the tree building stage and node optimization creating new nodes. This allows us to drop conversions previously done inside of nodes.


  • Do not enable deprecated plugins, the warnings about them break tests.

  • Ignore Qt binding warnings in tests, some are less supported than PySide6 or commercial PySide2.


The focus of this release was first a major restructuring of how children are handled in the node tree. The generated code opens up the possibility of many more scalability improvements in the coming releases. The pure iteration speed for the node tree will make compile times for the Python part even shorter in coming releases. Scalability will be a continuous focus for some releases.

Then the avoiding of API calls is a huge benefit for many platforms that are otherwise at a disadvantage. This is also only started. We will aim at getting more complex programs to do next to none of these, so far only some tests are working after program start without them, which is of course big progress. We will progress there with future releases as well.

Catching up on problems that previous migrations have not discovered is also a huge step forward to restoring the performance supremacy, that was not there anymore in extreme cases.

The Yaml package configuration work is showing its fruits. More people have been able to contribute changes for anti-bloat or missing dependencies than ever before.

Some part of the Python 3.11 work have positively influenced things, e.g. with the frame cleanup. THe focus of the next release cycle shall be to add support for it. Right now, generator frames need a cleanup to be finished, to also become better and working with 3.11 at the same time. Where possible, work to support 3.11 was also conducted as a cleanup action, or reduction of the technical debts.

All in all, it is fair to say that this release is a big leap forward in all kinds of ways.

Nuitka Release 1.3

This release contains a large amount of performance work, that should specifically be useful on Windows, but also generally. A bit of scalability work has been applied, and as usual many bug fixes and small improvements, many of which have been in hotfixes.

Bug Fixes

  • macOS: Framework build of PySide6 were not properly supporting the use of WebEngine. This requires including frameworks and resources in new ways, and actually some duplication of files, making the bundle big, but this seems to be unavoidable to keep the signature intact.

  • Standalone: Added workaround for dotenv. Do not insist on compiled package directories that may not be there in case of no data files. Fixed in 1.2.1 already.

  • Python3.8+: Fix, the ctypes.CDLL node attributes the winmode argument to Python2, which is wrong, it was actually added with 3.8. Fixed in 1.2.1 already.

  • Windows: Attempt to detect corrupt object file in MSVC linking. These might be produced by cl.exe crashes or clcache bugs. When these are reported by the linker, it now suggests to use the --clean-cache=ccache which will remove it, otherwise there would be no way to cure it. Added in 1.2.1 already.

  • Standalone: Added data files for folium package. Added in 1.2.1 already.

  • Standalone: Added data files for branca package. Added in 1.2.1 already.

  • Fix, some forms try that had exiting finally branches were tracing values only assigned in the try block incorrectly. Fixed in 1.2.2 already.

  • Alpine: Fix, Also include libstdc++ for Alpine to not use the system one which is required by its other binaries, much like we already do for Anaconda. Fixed in 1.2.2 already.

  • Standalone: Added support for latest pytorch. One of our workarounds no longer applies. Fixed in 1.2.2 already.

  • Standalone: Added support for webcam on Windows with opencv-python. Fixed in 1.2.3 already.

  • Standalone: Added support for pytorch_lightning, it was not finding metadata for rich package. Fixed in 1.2.4 already.

    For the release we found that pytorch_lightning may not find rich installed. Need to guard version() checks in our package configuration.

  • Standalone: Added data files for dash package. Fixed in 1.2.4 already.

  • Windows: Retry replace clcache entry after a delay, this works around Virus scanners giving access denied while they are checking the file. Naturally you ought to disable those for your build space, but new users often don’t have this. Fixed in 1.2.4 already.

  • Standalone: Added support for scipy 1.9.2 changes. Fixed in 1.2.4 already.

  • Catch corrupt object file outputs from gcc as well and suggest to clean cache as well. This has been observed to happen at least on Windows and should help resolve the ccache situation there.

  • Windows: In case clcache fails to acquire the global lock, simply ignore that. This happens sporadically and barely is a real locking issue, since that would require two compilations at the same time and for that it largely works.

  • Compatibility: Classes should have the f_locals set to the actual mapping used in their frame. This makes Nuitka usable with the multidispatch package which tries to find methods there while the class is building.

  • Anaconda: Fix, newer Anaconda versions have TCL and Tk in new places, breaking the tk-inter automatic detection. This was fixed in 1.2.6 already.

  • Windows 7: Fix, onefile was not working anymore, a new API usage was not done in a compatible fashion. Fixed in 1.2.6 already.

  • Standalone: Added data files for lark package. Fixed in 1.2.6 already.

  • Fix, pkgutil.iter_modules without arguments was given wrong compiled package names. Fixed in 1.2.6 already.

  • Standalone: Added support for newer clr DLLs changes. Fixed in 1.2.7 already.

  • Standalone: Added workarounds for tensorflow.compat namespace not being available. Fixed in 1.2.7 already.

  • Standalone: Added support for tkextrafont. Fixed in 1.2.7 already.

  • Python3: Fix, locals dict test code testing if a variable was present in a mapping could leak references. Fixed in 1.2.7 already.

  • Standalone: Added support for timm package. Fixed in 1.2.7 already.

  • Plugins: Add tls to list of sensible plugins. This enables at least pyqt6 plugin to do networking with SSL encryption.

  • Standalone: Added implicit dependencies of sklearn.cluster.

  • FreeBSD: Fix, fcopyfile is no longer available on newest OS version, and include files for sendfile have changed.

  • MSYS2: Add back support for MSYS Posix variant. Now onefile works there too.

  • Fix, when picking up data files from command line and plugins, different exclusions were applied. This has been unified to get better coverage for avoiding to include DLLs and the like as data files. DLLs are not data files and must be dealt with differently after all.

New Features

  • UI: Added new option for cache disabling --disable-cache that accepts all and cache names like ccache, bytecode and on Windows, dll-dependencies with selective values.


    The clcache is implied in ccache for simplicity.

  • UI: With the same values as --disable-cache Nuitka may now also be called with --clean-cache in a compilation or without a filename argument, and then it will erase those caches current data before making a compilation.

  • macOS: Added --macos-app-mode option for application bundles that should run in the background (background) or are only a UI element (ui-element).

  • Plugins: In the Nuitka package configuration files, the when allows now to check if a plugin is active. This allowed us to limit console warnings to only packages whose plugin was activated.

  • Plugins: Can now mark a plugin as a GUI toolkit responsible with the consequence that other toolkit detector plugins are all disabled, so when using tk-inter no longer will you be asked about PySide6 plugin, as that is not what you are using apparently.

  • Plugins: Generalized the GUI toolkit detection to include tk-inter as well, so it will now point out that wx and the Qt bindings should be removed for best results, if they are included in the compilation.

  • Plugins: Added ability to provide data files for macOS Resources folder of application bundles.

  • macOS: Fix, Qt WebEngine was not working for framework using Python builds, like the ones from PyPI. This adds support for both PySide2 and PySide6 to distribute those as well.

  • MSYS2: When asking a CPython installation to compress from the POSIX Python, it crashed on the main filename being not the same.

  • Scons: Fix, need to preserve environment attached modes when switching to winlibs gcc on Windows. This was observed with MSYS2, but might have effects in other cases too.


  • Python3.10+: When creating dictionaries, lists, and tuples, we use the newly exposed dictionary free list. This can speedup code that repeatedly allocates and releases dictionaries by a lot.

  • Python3.6+: Added fast path to dictionary copy. Compact dictionaries have their keys and values copied directly. This is inspired by a Python3.10 change, but it is applicable to older Python as well, and so we did.

  • Python3.9+: Faster compiled object creation, esp. on Python platforms that use a DLLs for libpython, which is a given on Windows. This makes up for core changes that went unnoticed so far and should regain relative speedups to standard Python.

  • Python3.10+: Faster float operations, we use the newly exposed float free list. This can speed up all kinds of float operations that are not doable in-place by a lot.

  • Python3.8+: On Windows, faster object tracking is now available, this previously had to go through a DLL call, that is now removed in this way as it was for non-Windows only so far.

  • Python3.7+: On non-Windows, faster object tracking is now used, this was regressed when adding support for this version, becoming equally bad as all of Windows at the time. However, we now managed to restore it.

  • Optimization: Faster deep copy of mutable tuples and list constants, these were already faster, but e.g. went up from 137% gain factor to 201% on Python3.10 as a result. We now use guided a deep copy, which then has the information, what types it is going to copy, removing the need to check through a dictionary.

  • Optimization: Also have own allocator function for fixed size objects. This accelerates allocation of compiled cells, dictionaries, some iterators, and lists objects.

  • More efficient code for object initialization, avoiding one DLL calls to set up our compiled objects.

  • Have our own PyObject_Size variant, that will be slightly faster and avoids DLL usage for len and size hints, e.g. in container creations.

  • Avoid using non-optimal malloc related macros and functions of Python, and instead of the fasted form generally. This avoids Python DLL calls that on Windows can be particularly slow.

  • Scalability: Generated child mixins are now used for the generated package metadata hard import nodes calls, and for all instances of single child tuple containers. These are more efficient for creation and traversal of the tree, directly improving the Python compile time.

  • Scalability: Slightly more efficient compile time constant property detections. For frozenset there was not need to check for hashable values, and some branches could be replaced with e.g. defining our own EllipsisType for use in short paths.

  • Windows: When using MSVC and LTO, the linking stage was done with only one thread, we now use the proper options to use all cores. This is controlled by --jobs much like C compilation already is. For large programs this will give big savings in overall execution time. Added in 1.2.7 already.

  • Anti-Bloat: Remove the use of pytest for dash package compilation.

  • Anti-Bloat: Remove the use of IPython for dotenv, pyvista, python_utils, and trimesh package compilation.

  • Anti-Bloat: Remove IPython usage in rdkit improving compile time for standalone by a lot. Fixed in 1.2.7 already.

  • Anti-Bloat: Avoid keras testing framework when using that package.


  • Plugins: The numpy plugin functionality was moved to Nuitka package configuration, and as a result, the plugin is now deprecated and devoid of functionality. On non-Windows, this removes unused duplications of the numpy.core DLLs.

  • User Manual: Added information about macOS entitlements and Windows console. These features are supported very well by Nuitka, but needed documentation.

  • UI: Remove alternative options from --help output. These are there often only for historic reasons, e.g. when an option was renamed. They should not bother users reading them.

  • Plugins: Expose the mnemonics option to plugin warnings function, and use it for pyside2 and pyqt5 plugins.

  • Quality: Detect trailing/leading spaces in Nuitka package configuration description values during their automatic check.

  • UI: Detect the CPython official flavor on Windows by comparing to registry paths and consider real prefixes, when being used in virtualenv more often, e.g. when checking for CPython on Apple.

  • UI: Enhanced --version output to include the C compiler selection. It is doing that respecting your other options, e.g. --clang, etc. so it will be helpful in debugging setup issues.

    UI: Some error messages were using %r rather than '%s' to output file paths, but that escaped backslashes on Windows, making them look worse, so we changed away from this.

  • UI: Document more clearly what --output-dir actually controls.

  • macOS: Added options hint that the Foundation module requires bundle mode to be usable.

  • UI: Allow using both --follow-imports and --nofollow-imports on command line rather than erroring out. Simply use what was given last, this allows overriding what was given in project options tests should the need arise.

  • Reports: Include plugin reasons for pre and post load modules provided. This solves a TODO and makes it easier to debug plugins.

  • UI: Handle --include-package-data before compilation, removing the ability to use pattern. This makes it easier to recognize mistakes without a long compilation and plugins can know them this way too.

  • GitHub: Migration workflows to using newer actions for Python and checkout. Also use newer Ubuntu LTS for Linux test runner.

  • UI: Catch user error of running Nuitka with the pythonw binary on Windows.

  • UI: Make it clear that MSYS2 defaults to --mingw64 mode. It had been like this, but the --help output didn’t say so.

  • GitHub: Updated contribution guidelines for better readability.

  • GitHub: Use organisation URLs everywhere, some were still pointing to the personal rather than the organisation one. While these are redirected, it is not good to have them like this.

  • Mastodon: Added link to to the PyPI package and User Manual.


  • Nodes for hard import calls of package meta data now have their base classes fully automatically created, replacing what was previously manual code. This aims at making them more consistent and easier to add.

  • When adding the new Scons file for C compiler version output, more values that are needed for both onefile and backend compilation were moved to centralized code, simplifying these somewhat again.

  • Remove unused main_module tag. It cannot happen that a module name matches, and still thinks of itself as __main__ during compilation, so that idea was unnecessary.

  • Generate the dictionary copy variants from template code rather than having manual duplications. For dict.copy(), for deep copy (needed e.g. when there are escaping mutable keyword argument constant values in say a function call), and for **kw value preparation in the called function (checking argument types), we have had diverged copies, that are now unified in a single Jinja2 template for optimization.

  • Plugins: Also allow providing generators for providing extra DLLs much like we already do for data files.

  • Naming of basic tests now makes sure to use a Test suffix, so in Visual Code selector they are more distinct from Nuitka code modules.

  • Rather than populating empty dictionaries, helper code now uses factory functions to create them, passing keys and values, and allowing values to be optional, removing noisy if branches at call side.

  • Removed remaining PyDev annotations, we don’t need those anymore for a long time already.

  • Cleanup, avoid lists objects for ctypes defined functions and their arglist, actually tuples are sufficient and naturally better to use.

  • Spelling cleanups were resumed, as an ongoing action.


  • Added construct test that demonstrates the mutable constant argument passing for lists to see the performance gains in this area too.

  • Made construct runner --diff output usable for interactive usage.

  • Repaired Nuitka Speedcenter, but it’s not yet too usable for general consumption. More work will be needed there, esp. to make comparisons more accessible for the general public.


The major achievement of this release was the removal of the long lived numpy plug-in, replacing it with package based configuration, that is even more optimal and works perfectly across all platforms on both important package installation flavors.

This release has a lot of consolidation efforts, but also as a result of 3.11 investigations, addresses a lot of issues, that have crept in over time with Python3 releases since 3.7, each time, something had not been noticed. There will more need for investigation of relative performance losses, but this should address the most crucial ones, and also takes advantage of optimization that had become with 3.10 already.

There is also some initial results from cleanups with the composite node tree structure, and how it is managed. Generated “child(ren) having” mixins, allow for faster traversal of the node tree.

Some technical things also improved in Scons. Using multiple cores in LTO with MSVC with help this a lot, although for big compilations --lto=no probably has to be recommended still.

More anti-bloat work on more packages rounds up the work.

For macOS specifically, the WebEngine support is crucial to some users, and the new --macos-app-mode with more GUI friendly default resolves long standing problems in this area.

And for MSYS2 and FreeBSD, support has been re-activated, so now 4 OSes work extremely well (others too likely), and on those, most Python flavors work well.

The performance and scalability improvements are going to be crucial. It’s a pity that 3.11 is not yet supported, but we will be getting there.

Nuitka Release 1.2

This release contains a large amount of new compatibility features and a few new optimization, while again consolidating what we have. Scalability should be better in many cases.

Bug Fixes

  • Standalone: Added implicit dependency of thinc backend. Fixed in 1.1.1 already.

  • Python3.10: Fix, match statements with unnamed star matches could give incorrect results. Fixed in 1.1.1 already.

    match x:
       case [*_, y]:
             ... # y had wrong value here.
  • Python3.9+: Fix, file reader objects must convert to str objects. Fixed in 1.1.1 already.

    # This was the `repr` rather than a path value, but it must be usable
    # like that too.
  • Standalone: Added data file of echopype package. Fixed in 1.1.1 already.

  • Anti-Bloat: Remove non-sense warning of compiled pyscf. Fixed in 1.1.1 already.

  • macOS: Fix, in LTO mode using incbin can fail, switch to source mode for constants resources. Fixed in 1.1.2 already.

  • Standalone: Add support for sv_ttk module. Fixed in 1.1.2 already.

  • macOS: Fix, was no longer correcting libpython path, this was a regression preventing CPython for creating properly portable binary. Fixed in 1.1.2 already.

  • macOS: Fix, main binary was not included in signing command. Fixed in 1.1.3 already.

  • Standalone: Added implicit dependency of orjson. Due to zoneinfo not being automatically included anymore, this was having a segfault. Fixed in 1.1.3 already.

  • Standalone: Added support for new shapely. Fixed in 1.1.4 already.

  • macOS: Ignore extension module of non-matching architecture. Some wheels contain extension modules for only x86_64 arch, and others contain them only for arm64, preventing the standalone build. Fixed in 1.1.4 already.

  • Standalone: Added missing sklearn dependencies. Fixed in 1.1.4 already.

  • Fix, packages available through relative import paths could be confused with the same ones imported by absolute paths. This should be very hard to trigger, by normal users, but was seen during development. Fixed in 1.1.4 already.

  • Standalone: Apply import hacks for pywin32 modules only on Windows, otherwise it can break e.g. macOS compilation. Fixed in 1.1.4 already.

  • Windows: More robust DLL dependency caching, otherwise e.g. a Windows update can break things. Also consider plugin contribution, and Nuitka version, to be absolutely sure, much like we already do for bytecode caching. Fixed in 1.1.4 already.

  • Standalone: Fix, seaborn needs the same workaround as scipy for corruption with MSVC. Fixed in 1.1.4 already.

  • UI: Fix, the options-nanny was no longer functional and therefore failed to warn about non working options and package usages. Fixed in 1.1.5 already.

  • macOS: Do not use extension modules of non-matching architecture. Fixed in 1.1.5 already.

  • Windows: Fix, resolving symlinks could fail for spaces in paths. Fixed in 1.1.6 already.

  • Standalone: Added missing DLL for lightgbm module. Fixed in 1.1.6 already.

  • Compatibility: Respect super module variable. It is now possible to have a module level change of super but still get compatible behavior with Nuitka. Fixed in 1.1.6 already.

  • Compatibility: Make sure we respect super overloads in the builtin module. Fixed in 1.1.6 already.

  • Fix, the anti-bloat replacement code for numpy.testing was missing a required function. Fixed in 1.1.6 already.

  • Fix, importlib.import_module static optimization was mishandling a module name of . with a package name given. Fixed in 1.1.6 already.

  • macOS: Fix, some extension modules use wrong suffixes in self references, we need to not complain about this kind of error. Fixed in 1.1.6 already.

  • Fix, do not make ctypes.wintypes a hard import on non-Windows. Nuitka asserted against it failing, where some code handles it failing on non-Windows platforms. Fixed in 1.1.6 already.

  • Standalone: Added data files for vedo package. Fixed in 1.1.7 already.

  • Plugins: Fix, the gi plugin did always set GI_TYPELIB_PATH even if already present from user code. Also it did not handle errors to detect its value during compile time. Fixed in 1.1.7 already.

  • Standalone: Added missing dependencies for sqlalchemy to have all SQL backends working. Fixed in 1.1.7 already.

  • Added support Nixpkgs’s default non-writable HOME directory. Fixed in 1.1.8 already.

  • Fix, distribution metadata name and package name need not align, need to preserve the original looked up name from importlib.metadata.distribution call. Fixed in 1.1.8 already.

  • Windows: Fix, catch usage of unsupported CLCACHE_MEMCACHED mode with MSVC compilation. It is just unsupported.

  • Windows: Fix, file version was spoiled from product version if it was the only version given.

  • Windows: The default for file description in version information was not as intended.

  • Plugins: Workaround for PyQt5 as contained in Anaconda providing wrong paths from the build machine.

  • macOS: After signing a binary with a certificate, compiling the next one was crashing on a warning about initially creating an ad-hoc binary.

  • Fix, detect case of non-writable cache path, make explaining error exit rather than crashing attempting to write to the cache.

  • macOS: Added support for pyobjc in version 9.0 or higher.

New Features

  • Python3.11: For now prevent the execution with 3.11 and give a warning to the user for a not yet supported version. This can be overridden with --experimental=python311 but at this times will not compile anything yet due to required and at this time missing core changes.

  • macOS: Added option --macos-sign-notarization that signs with runtime signature, but requires a developer certificate from Apple. As its name implies, this is for use with notarization for their App store.

  • DLLs used via delvewheel were so far only handled in the zmq plugin, but this has been generalized to cover any package using it. With that, e.g. shapely just works. This probably helps many other packages as well.

  • Added __compiled__ and __compiled_constant__ attributes to compiled functions.

    With this, it can be decided per function what it is and bridges like pyobjc can use it to create better code on their side for constant value returning functions.

  • Added support_info check to Nuitka package format. Make it clear that pyobjc is only supported after 9.0 by erroring out if it has a too low version. It will not work at all before that version added support in upstream. Also using this to make it clear that opencv-python is best supported in version 4.6 or higher. It seems e.g. that video capture is not working with 4.5 at this time.

  • Added --report-template which can be used to provide Jinja2 templates to create custom reports, and refer to built-in reports, at this time e.g. a license reports.


  • Trust the absence of a few selected hard modules and convert those to static raises of import errors.

  • For conditional nodes where only one branch exits, and the other does not, no merging of the trace collection should happen. This should enhance the scalability and leads to more static optimization being done after these kinds of branches on variables assigned in such branches.

    if condition1:
       a = 1
       raise KeyError
    if condition2:
       b = 1
    # Here, "a" is known to be assigned, but before it was only "maybe"
    # assigned, like "b" would have to be since, the branch may or may
    # not have been taken.
  • Do not merge tried blocks that are aborting with an exception handler that is not aborting. This is very similar to the change for conditional statements, again there is a control flow branch, that may have to be merged with an optional part, but sometimes that part is not optional from the perspective of the code following.

       ... # potentially raising, but not aborting code
       return something() # this aborts
    except Exception:
       a = 1
       ... # potentially raising, but not aborting code
    except Exception:
       b = 1
    # Here, "a" is known to be assigned, but before it was only "maybe"
    # assigned, like "b" would have to be since, the branch may or may
    # not have been taken.
  • Exception matches were annotating a control flow escape and an exception exit, even when it is known that no error is possible to be happening that comparison.

    except ImportError: # an exception match is done here, that cannot raise
  • Trust importlib.metadata.PackageNotFoundError to exist, with this some more metadata usages are statically optimized. Added in 1.1.4 already.

  • Handle constant values from trusted imports as trusted values. So far, trusted import values were on equal footing to regular variables, which on the module level could mean that no optimization was done, due to control flow escapes happening.

    # Known to be False at compile time.
    from typing import TYPE_CHECKING
       from something import normally_unused_unless_type_checking

    In this code example above, the static optimization was not done because the value may be changed on the outside. However, for trusted constants, this is no longer assumed to be happening. So far only if typing.TYPE_CHECKING: using code had been optimized.

  • macOS: Use sections for main binary constants binary blob rather than C source code (which we started in a recent hotfix due to LTO issues with incbin) and onefile payload. The latter enables notarization of the onefile binary as well and makes it faster to unpack as well.

  • Windows: Do not include DLLs from SxS. For PyPI packages these are generally unused, and self compiled modules won’t be SxS installations either. We can add it back where it turns out needed. This avoids including comctl32 and similar DLLs, which ought to come from the OS, and might impede backward compatibility only.

  • Disabled C compilation of very large azure modules.

  • The per module usage information of other modules was only updated in first pass was used in later passes. But since they can get optimized away, we have to update every time, avoiding to still include unused modules.

  • Anti-Bloat: Fight the use of dask in xarray and pint, adding a mode controlling its use. This is however still incomplete and needs more work.

  • Fix, the anti-bloat configuration for rich.pretty introduced a SyntaxError that went unnoticed. In the future compilation will abort when this happens.

  • Standalone: Added support for including DLLs of llvmlite.binding package.

  • Anti-Bloat: Avoid using pywin32 through pkg_resources import. This seems rather pointless and follows an optimization done for the inline copy of Nuitka already, the ctypes code path works just fine, and this may well be the only reason why pywin32 is included, which is by itself relatively large.

  • Cache directory contents when scanning for modules. The sys.path and package directories were listed over and over, wasting time during the import analysis.

  • Optimization: Was not caching not found modules, but retrying every time for each usage, potentially wasting time during import analysis.

  • Anti-Bloat: Initial work to avoid pytest in patsy, it is however incomplete.


  • User Manual: Explain how to create 64/32 bits binaries on Windows, with there being no option to control it, this can otherwise be a bit unobvious that you have to just use the matching Python binary.

  • UI: Added an example for a cached onefile temporary location spec to the help output of --onefile-tempdir-spec to make cached more easy to achieve in the proper way.

  • UI: Quote command line options with space in value better, no need to quote an affected command line option in its entirety, and it looks strange.

  • macOS: Catch user error of disabling the console without using the bundle mode, as it otherwise it has no effect.

  • macOS: Warn about not providing an icon with disabled console, otherwise the dock icon is empty, which just looks bad.

  • Debian: Also need to depend on glob2 packages which the yaml engine expects to use when searching for DLLs.

  • Debian: Pertain inline copies of modules in very old builds, there is e.g. no glob2 for older releases, but only recent Debian releases need very pure packages, our backport doesn’t have to do it right.

  • macOS: More reliable detection of Homebrew based Python. Rather than checking file system via its sitecustomize contents. The environment variables are only present to some usages.

  • Installations with pip did not include all license, README files, etc. which however was intended. Also the attempt to disable bytecode compilation for some inline copies was not effective yet.

  • Renamed pyzmq plugin to delvewheel as it is now absolutely generic and covers all uses of said packaging technique.

  • Caching: Use cache directory for cached downloads, rather than application directory, which is just wrong. This will cause all previously cached downloads to become unused and repeated.

  • Quality: Updated development requirements to latest black, isort, yamllint, and tqdm.

  • Visual Code: Added recommendation for extension for Debian packaging files.

  • Added warning for PyQt5 usage, since its support is very incomplete. Made the PyQt6 warning more concrete. It seems only Qt threading does not work, which is of course still significant. Instead PySide2 and PySide6 are recommended.

  • UI: Have dedicated options group for onefile, the spec for the temporary files is not a Windows option at all anymore. Also move the warnings group to the end, people need to see the inclusion related group first.

  • User Manual: Explain how to create 64/32 bits binaries on Windows, which is not too obvious.


  • Moved PySide plugins DLL search extra paths to the Yaml configuration. In this way it is not dependent on the plugin being active, avoiding cryptic errors on macOS when they are not found.

  • Plugins: Avoid duplicate link libraries due to casing. We are now normalizing the link library names, which avoids e.g. Shell32 and shell32 to be in the result.

  • Cleanups to prepare a PyLint update that so otherwise failed due to encountered issues.

  • Plugins: Pass so called build definitions for generically. Rather than having dedicated code for each, and plugins can now provide them and pass their index to the scons builds.

  • Onefile: Moved file handling code to common code reducing code duplication and heavily cleaning up the bootstrap code generally.

  • Onefile: The CRC32 checksum code was duplicated between constants blob and onefile, and has moved to shared code, with an actual interface to take the checksum.

  • Spelling cleanups resumed, e.g. this time more clearly distinguishing between run time and runtime, the first is when the program executes, but the latter can be an environment provided by a C compiler.


  • Tests: Added test that applies anti-bloat configuration to all found modules.

  • Tests: Tests: Avoid including unused code in reflected test, which should make it faster. The compiler itself doesn’t use that code.


This release is again mainly a consolidation of previous release, as well as finishing off existing features. Optimization added in previous releases should have all regressions fixed now, again with a strong series of hotfixes.

New optimization was focused around findings with static optimization not being done, but still resulting in general improvements. Letting static optimization drive the effort is still paying off.

Scalability has seen improvements through some of the optimization, this time a lot less anti-bloat work has been done, and some things are only started. The focus will clearly now shift to making this a community effort. Expect postings that document the Yaml format we use.

For macOS specifically, with the sections work, onefile should launch faster, should be more compatible with signing, and can now be used in notarization, so for that platform, things are more round.

For Windows, a few issues with version information and onefile have been addressed. We should be able to use memory mapped view on this platform too, for faster unpacking of the payload, since it doesn’t have to go through the file anymore.

Nuitka Release 1.1

This release contains a large amount of new compatibility features, while consolidating what we have. Scalability should be better in some cases.

Bug Fixes

  • Standalone: Enhanced dependency scan of dependent DLLs to forward the containing package, so it can be searched in as well. This fixed at least PySide on macOS. Fixed in 1.0.1 already.

  • macOS: Enhanced dependency detection to use normalized paths and therefore to be more stable. Fixed in 1.0.1 already.

  • Standalone: Added support for the networkx package which uses new support for a function decorator trying to copy function default values. Fixed in 1.0.1 already.

  • Standalone: Include data files for package. This one has Jinja2 template files that will be needed when using this package.

  • Python3.10: Fix, could crash in case a class was not giving match arguments, but the user did attempt to match them. This happened e.g. with range objects. Fixed in 1.0.2 already.

  • Standalone: Added data files needed for pyenchant package. Fixed in 1.0.2 already.

  • Python3.10: Fix, matching sequence with as assignments in them didn’t check for sub-pattern given. Fixed in 1.0.2 already.

  • Standalone: Fix, do not attempt to list non-existent PATH entries on Windows, these can crash the dependency detection otherwise. Fixed in 1.0.2 already.

  • Standalone: Fix, on newer Linux, appears in output of ldd in a way that suggests it may exist, which of course it does not, this is a kernel virtual DLL. Fixed in 1.0.3 already.

  • Fix, comparison expressions could give wrong results as a regression of the new release. Fixed in 1.0.3 already.

  • Fix, on older Python (before 3.6), it could crash on data files defined in the Yaml config. Fixed in 1.0.4 already.

  • Fix, binary operations could give wrong results as a regression of the new release. Fixed in 1.0.4 already.

  • Standalone: Added support for pyzbar package. Fixed in 1.0.5 already.

  • Standalone: Fix, empty directory structures were not working anymore due to a regression in the last release. Fixed in 1.0.5 already.

  • Windows: Fix, detected Pythons from Windows registry may of course fail to execute, because they were e.g. manually deleted. This would show e.g. in onefile compression. Fixed in 1.0.5 already.

  • Onefile: Fix, using a too old zstandard without finding another Python with a suitable one, lead to run time unpacking errors. Fixed in 1.0.6 already.

  • Fix, the inline copy of Jinja2 imported logging for no good reason, which lead to errors for users who have a module of the same name, that it was then using instead. Fixed in 1.0.6 already.

  • Fix, disable LTO mode for Anaconda Python, it is known to not work. Fixed in 1.0.6 already.

  • Linux: Fix, no need to insist on icon path for onefile anymore. Fixed in 1.0.6 already.

  • Standalone: Fix, the new version certifi was not working on Windows and 3.10 anymore. Fixed in 1.0.7 already.

  • Standalone: Added support for more rapidfuzz implicit dependencies. Fixed in 1.0.8 already.

  • Standalone: Added support for vibora. Fixed in 1.0.8 already.

  • Fix, must not expose module name objects to Python import hooks. Fixed in 1.0.8 already.

  • Fix, calls to bound methods of string values generated incorrect calls. Fixed in 1.0.8 already.

  • Fix, do not crash in version detection on gcc error exit querying of its version.

  • Standalone: Added back support for older versions of the pyzmq package.

  • Standalone: Ignore PATH elements that fail to be listed as a directory. It appears e.g. on Windows, folders can exist, despite being unusable in fact. These can then cause errors in DLL dependency scan. Also avoid having PATH set when executing dependency walker, it appears to use it even if not asked to.

  • Standalone: Added support for tzlocal package.

  • Python3.10: Fix, complex literals were not working for mappings in match statements.

  • Fix, bool built-in expressions were not properly annotating exception raises, where the value cannot raise on truth check.

  • Standalone: Added support for the agscheduler package. Plugins must be done manually still with explicit --include-module calls.

  • Standalone: Added support for using shapely in Anaconda as well.

  • Debian: Fix, versioned dependency for libzstd should also be in package, this should restore Nuitka package builds for Debian Jessie.

  • Standalone: Added support for vtk package.

  • Windows: Fix, avoid using pywin32 in our appdirs usage, it might be a broken installation and is optional to appdirs anyway, which then will fallback to using ctypes to make the lookups.

  • Standalone: Added support for more pandas versions.

  • Standalone: Adding support for mkl implicit DLL usage in Anaconda.

  • Standalone: Added support for jsonschema with Python 3.10.

  • Standalone: Added support for pyfiglet fonts data files.

  • Scons: Avoid gcc linker command line length limits for module mode too.

  • Standalone: Added data file of distributed.config.

  • Standalone: Add support for cv2 GUI on Linux, the Qt platform plugin is now included.

  • Fix, the anti-bloat configuration for numpy.testing tools exposed an incomplete suppress_warnings replacement that could lead to errors in some functions of numpy.

  • Standalone: Fix DLL dependency caching on Windows, need to consider DLL content of course too.

  • Standalone: Added missing dependency for torchvision.

  • Standalone: Added support for torchvision on Anaconda as well.

  • Standalone: Added support for panda3d.

  • Windows: Fix, need to make sure to use UTF-8 encoding for define values like company name. Otherwise the local system encoding is used, but the C compiler expects UTF-8 in wide literals. This may crash of give wrong results.

  • Standalone: Added facenet_torch data files.

  • Anaconda: Include on Linux or else e.g. cv2 will not work with system library.

  • Windows: Fix, can have file version without a company name.

New Features

  • Python3.10: Added support for assignments in match alternatives | syntax.

  • Compatibility: Register Nuitka meta path based loader with pkg_resources such that checking resource presence with has_resource works too. This should also add support for using jinja2.PackageLoader, previously only jinja2.FileSystemLoader worked. Fixed in 1.0.1 already.

  • Compatibility: Make function __defaults__ attribute size changeable. For a long time, this was a relatively big issue for some packages, but now this is supported as well.

  • Compatibility: Added support for importlib.metadata.distribution and importlib_metadata.distribution functions as well importlib.metadata.metadata and importlib_metadata.metadata functions.

  • Onefile: Added support for including other binaries than the main executable in the payload. So far on non-Windows, we only made the main binary executable, hard coded, and nothing else. But Some things, e.g. Qt web engine, do require binaries to be used, and these no longer have the issue of missing x-bit on macOS and Linux now.

  • Standalone: Resolve executable path when called through symbolic link, which makes file resolutions work properly for it, for this type of installing it in %PATH%.

  • Python3.9+: Added support for importlib.resources.files with compiled modules.

    It returns traversable objects, which can be used to opens files, checks them, etc. and this e.g. allows jsonschema to work with Python 3.10, despite bugs in CPython’s compatibility layer.

  • UI: Added interface method to specify filename patterns with package data inclusion option, making --include-package-data usable in many more cases, picking the only files or file types you want. You can now use --include-package-data=package_name=*.txt and select only a subset of package data files in this way. Before this, it included everything and --noinclude-data-files would have to be used.

  • macOS: Make runtime signing an experimental option.

  • Consistently allow when conditions for all package configuration elements, e.g. also DLLs.

  • Plugins: Added method to overload to work on standalone binary specifically. This makes it easier to only modify that specific binary.

  • Plugins: Added support for regular expressions in anti-bloat replacements, with new replacements_re code.


  • Add support for os.path hard module imports along with specialized nodes for file tests os.path.exists, os.path.isfile, and os.path.isdir aiming at tracking used files, producing warnings about missing files in the future.

  • Standalone: Do not include concurrent standard library package automatically. This avoids the inclusion of multiprocessing which we essentially had reverted during last release cycle.

  • Standalone: Do not include zoneinfo standard library package automatically. It has many data files and is often not used (yet).

  • Standalone: Do not include asyncio standard library package automatically anymore.

  • Avoid compilation of large generated codes in the asyncua package.

  • Compile time optimize pkg_resources.iter_entry_points too, such that these can be used to resolve plugin modules, which helps with adding support for agscheduler package plugins. Note that these still need to be manually included with --include-module but now that works.

  • For known truth values of the right hand side of and or or conditions, reduce the expression as far as possible.

  • Added dedicated assignment node for hard imports, which then are propagated in classes as well, allowing for more static optimization for code on the class level.

  • Added linker options to make static --static-libpython work with clang on Linux as well.

  • macOS: Make sure libpython is loaded relative to the executable. This is needed for at least Anaconda Python.

  • macOS: Fix, need to search environment specific DLL paths and only then global paths, otherwise mixed Python versions will not work correctly.

  • Anti-Bloat: Remove IPython usage in rich package.

  • Anti-Bloat: Avoid doctest dependency when using pyrect.

  • Anti-Bloat: Some unittest removals from pytorch using libraries.

  • Keep the Scons report items sorted, or else it varies for the hashing of dependencies with Python versions before 3.6, causing cache misses without need.


  • UI: Output the .cmd file created (if any) on Windows, e.g. when run in a virtualenv or for uninstalled Python versions, it will otherwise not run in accelerated mode, but previously the output suggested to run the executable directly.

  • UI: Enhanced command line option description of --include-plugin-directory which is frequently misunderstood. That option barely does what people want it to do. Point them to using the other options that are easy to use and will work.

  • UI: Specified needed Python version for use in --python-for-scons so users can know ahead of time what versions are suitable.

  • Reports: Added information about data files including, optimization times per module, active plugins.

  • Debugging: Repaired offline DLL dependency listing tool, such that it can be used during Windows DLL analysis.

  • Make --xml accept a filename for the node tree dump, and change it so it can be executed in addition to actual compilation. This way we need not be super-robust about keeping stdout clean, to not break XML parsing.

  • Plugins: Avoid useless warning about PySide2 plugin usage if another Qt plugin is actually selected.

  • UI: Catch error of directories being used as data files where plain files are expected and point out that other options must be used.

  • User Manual: Added section about accessing files in standalone mode too, so people can make sure it works properly.

  • Onefile: Using %TEMP% folder should not by itself prevent cached onefile mode, only really variable paths should. People may want to have this as some kind of temporary cache still.

  • UI: Catch user error of using elements, that resolve to absolute values in the middle of path specs, so using e.g. something/%PROGRAM% is now a mistake caught at compile time. These values can only be at the start of spec values naturally.

  • Quality: Updated to newer version of rstfmt.

  • UI: Nicer error message when a forbidden import is requested as an implicit import by a plugin.

  • Python3.11: Adapted to allocator and exception state changes, but more will be needed to compile at all.

  • Visual Code: Find clang-format from the recommended C++ extension of Visual Code, which makes it finally available on macOS easily too.

  • UI: Quote command line argument values as necessary when stating them in the logging. Otherwise they are not directly usable on the shell and also less readable.

  • Debian: Do not list fake modules as used debian packages codes, which could e.g. happen with the pre-load code of pkg_resources if that is from a Debian package. Fake packages should not be mentioned for these lists though.

  • Nuitka-Python: Added support to set link time flags coming from statically included packages.

  • For our isort trick of splitting files in two parts (mostly to setup import paths for nuitka package), make sure the second parts starts with a new line.

  • Added more usable form --output-filename to specify the output filename, the short form has become barely usable after we switched to enforcing no space separation for command line arguments.

  • UI: Check if output filename’s directory exists ahead of time, and error exit if not, otherwise compilation crashed only in the very end, trying to create the final result.

  • UI: When exiting with no error code, do not use red color or FATAL error annotation, that is not justified.

  • Quality: Make sure the Yaml auto-format does not change effective contents.

  • Quality: Added ability to limit autoformat by file type, which can be handy when e.g. only the yaml files should be scanned.

  • UI: Removed --windows-onefile-tempdir-spec alias of --onefile-tempdir-spec option, it is no longer Windows specific.


  • Prefer single quotes rather than double quotes in our package configuration Yaml files, otherwise esp. regular expressions with escapes become very confusing.

  • Move import hacks to general mechanism in Yaml package configuration files. This is for extra paths from package names or from directory paths relative to the package. This removes special purpose code from core code paths and allows their reuse.

  • Again more spelling cleanups have been done, to make the code cleaner to read and search.

  • Unified how plugins treat iteration over their value list, and how the when condition is applied for the various kinds of sections.

  • Output compilation command that failed during coverage taking, which makes it unnecessary to attempt to reconstruct what happened from test modes.


  • Added coverage for comparisons that need argument swaps.

  • Allow more time in onefile keyboard signal test, otherwise it can be a race on slow machines, e.g. emulated machines.

  • Tests: Added support for running a local web server.


This release is mainly a consolidation of previous release. Optimization added in previous release did in fact introduce regressions, that needed to be addressed and were cause for relatively many hotfixes.

The Yaml nuitka package configuration feature is getting ever more powerful, but is not one bit more documented, such that the community as a whole is not yet capable of adding missing dependencies, data files, DLLs, and even anti-bloat patches.

New optimization was focused around compatibility with very few exceptions, where the non-automatic standard library work is standing out, and allows for smaller binaries in many cases.

Scalability has seen improvements through a few optimization, but mainly again with anti-bloat work being done. This is owed to the fact that consolidation was the name of the game.

For Anaconda specifically, a lot more software is covered, and generally, cv2 and torch related tools are now working better, but it seems DLL handling will remain problematic in many instances.

The compilation report contains much more information and is getting there is terms of completeness. At some point, we should ask for it in bug reports.

Nuitka Release 1.0

This release contains a large amount of new features, while consolidating what we have with many bug fixes. Scalability should be dramatically better, as well as new optimization that will accelerate some code quite a bit. See the summary, how this release is paving the way forward.

Bug Fixes

  • Python3: Fix, bytes.decode with only errors argument given was not working. Fixed in 0.9.1 already.

  • MSYS2: Fix, the accelerate mode .cmd file was not working correctly. Fixed in 0.9.1 already.

  • Onefile: Fix, the bootstrap when waiting for the child, didn’t protect against signals that interrupt this call. This only affected users of the non-public --onefile-tempdir option on Linux, but with that becoming the default in 1.0, this was discovered. Fixed in 0.9.1 already.

  • Fix, pkg_resources compile time generated Distribution values could cause issues with code that put it into calls, or in tried blocks. Fixed in 0.9.1 already.

  • Standalone: Added implicit dependencies of Xlib package. Fixed in 0.9.1 already.

  • macOS: Fix, the package configuration for wx had become invalid when restructuring the Yaml with code and schema disagreeing on allowed values. Fixed in 0.9.1 already.

  • Fix: The str.format with a single positional argument didn’t generate proper code and failed to compile on the C level. Fixed in 0.9.1 already.

  • Fix, the type shape of str.count result was wrong. Fixed in 0.9.1 already.

  • UI: Fix, the warning about collision of just compiled package and original package in the same folder hiding the compiled package should not apply to packages without an file, as those do not take precedence. Fixed in 0.9.2 already.

  • Debugging: Fix, the fallback to lldb from gdb when using the option --debugger was broken on anything but Windows. Fixed in 0.9.2 already.

  • Python3.8: The module importlib.metadata was not recognized before 3.9, but actually 3.8 already has it, causing the compile time resolution of package versions to not work there. Fixed in 0.9.3 already.

  • Standalone: Fix, at least on macOS we should also scan from parent folders of DLLs, since they may contain sub-directories in their names. This is mostly the case, when using frameworks. Fixed in 0.9.2 already.

  • Standalone: Added package configuration for PyQt5 to require onefile bundle mode on macOS, and recommend to disable console for PyQt6. This is same as we already do for PySide2 and PySide6. Fixed in 0.9.2 already.

  • Standalone: Removed stray macOS onefile bundle package configuration for pickle module which must have been added in error. Fixed in 0.9.2 already.

  • UI: Catch user error of attempting to compile the rather than the package directory. Fixed in 0.9.2 already.

  • Fix, hard name import nodes failed to clone, causing issues in optimization phase. Fixed in 0.9.2 already.

  • Fix, avoid warnings given with gcc 11. Fixed in 0.9.2 already.

  • Fix, dictionary nodes where the operation itself has no effect, e.g. dict.copy were not properly annotating that their dictionary argument could still cause a raise and have side effects, triggering an assertion violation in Nuitka. Fixed in 0.9.2 already.

  • Standalone: Added pynput implicit dependencies on Linux. Fixed in 0.9.2 already.

  • Fix, boolean condition checks on variables converted immutable constant value assignments to boolean values, leading to incorrect code execution. Fixed in 0.9.2 already.

  • Python3.9: Fix, could crash on generic aliases with non-hashable values. Fixed in 0.9.3 already.

  • Python3: Fix, an iteration over sys.version_info was falsely optimized into a tuple, which is not always compatible. Fixed in 0.9.3 already.

  • Standalone: Added support for xgboost package. Fixed in 0.9.3 already.

  • Standalone: Added data file for text_unidecode package. Fixed in 0.9.4 already.

  • Standalone: Added data files for swagger_ui_bundle package. Fixed in 0.9.4 already.

  • Standalone: Added data files for connexion package. Fixed in 0.9.4 already.

  • Standalone: Added implicit dependencies for sklearn.utils and rapidfuzz. Fixed in 0.9.4 already.

  • Python3.10: Fix, the reformulation of match statements could create nodes that are used twice, causing code generation to assert. Fixed in 0.9.4 already.

  • Fix, module objects removed from sys.modules but still used could lack a reference to themselves, and therefore crash due to working on a released module variables dictionary. Fixed in 0.9.5 already.

  • Fix, the MSVC compiles code generated for SciPy 1.8 wrongly. Added a workaround for that code to avoid triggering it. Fixed in 0.9.6 already.

  • Fix, calls to str.format where the result is not used, could crash the compiler during code generation. Fixed in 0.9.6 already.

  • Standalone: For DLLs on macOS and Anaconda, also consider the lib directory of the root environment, as some DLLs are otherwise not found.

  • Fix, allow nonlocal and global for __class__ to be used on the class level.

  • Fix, xrange with large values didn’t work on all platforms. This affected at least Python2 on macOS, but potentially others as well.

  • Windows: When scanning for installed Pythons to e.g. run Scons or onefile compression, it was attempting to use installations that got deleted manually and could crash.

  • macOS: Fix, DLL conflicts are now resolved by checking the version information too, also all cases that previously errored out after a conflict was reported, will now work.

  • Fix, conditional expressions whose statically decided condition picking a branch will raise an exception could crash the compilation.

    # Would previously crash Nuitka during optimization.
    return 1/0 if == "nt" else 1/0
  • Windows: Make sure we set C level standard file handles too

    At least newer subprocess was affected by this, being unable to provide working handles to child processes that pass their current handles through, and also this should help DLL code to use it as level.

  • Standalone: Added support for pyqtgraph data files.

  • Standalone: Added support for dipy by anti-bloat removal of its testing framework that wants to do unsupported stuff.

  • UI: Could still give warnings about modules not being followed, where that was not true.

  • Fix, --include-module was not working for non-automatic standard library paths.

New Features

  • Onefile: Recognize a non-changing path from --onefile-tempdir-spec and then use cached mode. By default a temporary folder is used in the spec value, make it delete the files afterwards.

    The cached mode is not necessarily faster, but it is not going to change files already there, leaving the binaries there intact. In the future it may also become faster to execute, but right now checking the validity of the file takes about as long as re-creating it, therefore no gain yet. The main point, is to not change where it runs from.

  • Standalone: Added option to exclude DLLs. You can npw use --noinclude-dlls to exclude DLLs by filename patterns.

    The may e.g. come from Qt plugins, where you know, or experimented, that it is not going to be used in your specific application. Use with care, removing DLLs will lead to very hard to recognize errors.

  • Anaconda: Use CondaCC from environment variables for Linux and macOS, in case it is installed. This can be done with e.g. conda install gcc_linux-64 on Linux or conda install clang_osx-64 on macOS.

  • Added new option --nowarn-mnemonic to disable warnings that use mnemonics, there is currently not that many yet, but it’s going to expand. You can use this to acknowledge the ones you accept, and not get that warning with the information pointer anymore.

  • Added method for resolving DLL conflicts on macOS too. This is using version information and picks the newer one where possible.

  • Added option --user-package-configuration-file for user provided Yaml files, which can be used to provide package configuration to Nuitka, to e.g. add DLLs, data files, do some anti-bloat work, or add missing dependencies locally. The documentation for this does not yet exist though, but Nuitka contains a Yaml schema in the misc/nuitka-package-config-schema.json file.

  • Added nuitka-project-else to avoid repeating conditions in Nuitka project configuration, this can e.g. be used like this:

    # nuitka-project-if: os.getenv("TEST_VARIANT", "pyside2") == "pyside2":
    #   nuitka-project: --enable-plugin=no-qt
    # nuitka-project-else:
    #   nuitka-project: --enable-plugin=no-qt
    #   nuitka-project: --noinclude-data-file=*.svg

    Previously, the inverted condition had to be used in another nuitka-project-if which is no big deal, but less readable.

  • Added support for deep copying uncompiled functions. There is now a section in the User Manual that explains how to clone compiled functions. This allows a workaround like this:

    def binder(func, name):
          result = func.clone()
       except AttributeError:
          result = types.FunctionType(func.__code__, func.__globals__, name=func.__name__, argdefs=func.__defaults__, closure=func.__closure__)
          result = functools.update_wrapper(result, func)
          result.__kwdefaults__ = func.__kwdefaults__
       result.__name__ = name
       return result
  • Plugins: Added explicit deprecation status of a plugin. We now have a few that do nothing, and are just there for compatibility with existing users, and this now informs the user properly rather than just saying it is not relevant.

  • Fix, some Python installations crash when attempting to import modules, such as os with a ModuleName object, because we limit string operations done, and e.g. refuse to do .startswith which of course, other loaders that your installation has added, might still use.

  • Windows: In case of not found DLLs, we can still examine the run time of the currently compiling Python process of Nuitka, and locate them that way, which helps for some Python configurations to support standalone, esp. to find CPython DLL in unusual spots.

  • Debian: Workaround for lib2to3 data files. These are from stdlib and therefore the patched code from Debian needs to be undone, to make these portable again.


  • Scalability: Avoid merge traces of initial variable versions, which came into play when merging a variable used in only one branch. These are useless and only made other optimization slower or impossible.

  • Scalability: Also avoid merge traces of merge traces, instead flatten merge traces and avoid the duplication doing so. There were pathological cases, where this reduced optimization time for functions from infinite to instant.

  • For comparison helpers, switch comparison where possible, such that there are only 3 variants, rather than 6. Instead the boolean result is inverted, e.g. changing >= into not < effectively. Of course this can only be done for types, where we know that nothing special, i.e. no method overloads of __gte__ is going on.

  • For binary operations that are commutative with the selected types, in mixed type cases, swap the arguments during code generation, such that e.g. long_a + float_b is actually computed as float_b + long_a. This again avoids many helpers. It also can be done for * with integers and container types.

  • In cases, where a comparison (or one of the few binary operation where we consider it useful), is used in a boolean context, but we know it is impossible to raise an exception, a C boolean result type is used rather than a nuitka_bool which is now only used when necessary, because it can indicate the exception result.

  • Anti-Bloat: More anti-bloat work was done for popular packages, covering also uses of setuptools_scm, nose and nose2 package removals and warnings. There was also a focus on making mmvc, tensorflow and tifffile compile well, removing e.g. the uses of the tensorflow testing framework.

  • Faster comparison of int values with constant values, this uses helpers that work with C long values that represent a single “digit” of a value, or ones that use the full value space of C long.

  • Faster comparison of float values with constant values, this uses helpers that work with C float values, avoiding the useless Python level constant objects.

  • Python2: Comparison of int and long now has specialized helpers that avoids converting the int to a long through coercion. This takes advantage of code to compare C long values (which are at the core of Python2 int objects, with long objects.

  • For binary operation on mixed types, e.g. int * bytes the slot of the first function was still considered, and called to give a Py_NotImplemented return value for no good reason. This also applies to mixed operations of int, long, and float types, and for str and unicode values on Python2.

  • Added missing helper for ** operation with floats, this had been overlooked so far.

  • Added dedicated nodes for ctypes.CDLL which aims to allow us to detect used DLLs at compile time in the future, and to move closer to support its bindings more efficiently.

  • Added specialized nodes for dict.popitem as well. With this, now all of the dictionary methods are specialized.

  • Added specialized nodes for str.expandtabs, str.translate, str.ljust, str.rjust,, str.zfill, and str.splitlines. While these are barely performance relevant, this completes all str methods, except removeprefix and removesuffix that are Python3.9 or higher.

  • Added type shape for result of str.index operation as well, this was missing so far.

  • Optimize str, bytes and dict method calls through variables.

  • Optimize calls through variables containing e.g. mutable constant values, these will be rare, because they all become exceptions.

  • Optimize calls through variables containing built-in values, unlocking optimization of such calls, where it is assigned to a local variable.

  • For generated attribute nodes, avoid local doing import statements on the function level. While these were easier to generate, they can only be slow at run time.

  • For the str built-in annotate its value as derived from str, which unfortunately does not allow much optimization, since that can still change many things, but it was still a missing attribute.

  • For variable value release nodes, specialize them by value type as well, enhancing the scalability, because e.g. parameter variable specific tests, need not be considered for all other variable types as well.


  • Plugins: Major changes to the Yaml file content, cleaning up some of the DLL configuration to more easy to use.

    The DLL configuration has two flavors, one from code and one from filename matching, and these got separated into distinct items in the Yaml configuration. Also how source and dest paths get provided got simplified, with a relative path now being used consistently and with sane defaults, deriving the destination path from where the module lives. Also what we called patterns, are actually prefixes, as there is still the platform specific DLL file naming appended.

  • Plugins: Move mode checks to dedicated plugin called options-nanny that is always enabled, giving also much cleaner Yaml configuration with a new section added specifically for these. It controls advice on the optional or required use of --disable-console and the like. Some packages, e.g. wx are known to crash on macOS when the console is enabled, so this advice is now done with saner configuration.

  • Plugins: Also for all Yaml configuration sub-items where is now a consistent when field, that allows checking Python version, OS, Nuitka modes such as standalone, and only apply configuration when matching this criterion, with that the anti-bloat options to allow certain bloat, should now have proper effect as well.

  • The use of AppImage on Linux is no more. The performance for startup was always slower, while having lost the main benefit of avoiding IO at startup, due to new cached mode, so now we always use the same bootstrap binary as on macOS and Windows.

  • UI: Do not display implicit reports reported by plugins by default anymore. These have become far too many, esp. with the recent stdlib work, and often do not add any value. The compilation report will become where to turn to find out why a module in included.

  • UI: Ask the user to install the ordered set package that will actually work for the specific Python version, rather than making him try one of two, where sometimes only one can work, esp. with Python 3.10 allowing only one.

  • GitHub: More clear wording in the issue template that python -m nuitka --version output is really required for support to given.

  • Attempt to use Anaconda ccache binary if installed on non-Windows. This is esp. handy on macOS, where it is harder to get it.

  • Windows: Avoid byte-compiling the inline copy of Scons that uses Python3 when installing for Python2.

  • Added experimental switches to disable certain optimization in order to try out their impact, e.g. on corruption bugs.

  • Reports: Added included DLLs for standalone mode to compilation report.

  • Reports: Added control tags influencing plugin decisions to the compilation report.

  • Plugins: Make the implicit-imports dependency section in the Yaml package configuration a list, for consistency with other blocks.

  • Plugins: Added checking of tags such from the package configuration, so that for things dependent on python version (e.g. python39_or_higher, before_python39), the usage of Anaconda (anaconda) or certain OS (e.g. macos), or modes (e.g. standalone), expressions in when can limit a configuration item.

  • Quality: Re-enabled string normalization from black, the issues with changes that are breaking to Python2 have been worked around.

  • User Manual: Describe using a minimal virtualenv as a possible help low memory situations as well.

  • Quality: The yaml auto-format now properly preserves comments, being based on ruamel.yaml.

  • Nuitka-Python: Added support for the Linux build with Nuitka-Python for our own CPython fork as well, previously only Windows was working, amd macOS will follow later.

  • The commit hook when installed from git bash was working, but doing so from cmd.exe didn’t find a proper path for shell from the git location.

  • Debugging: A lot of experimental toggles were added, that allow control over the use of certain optimization, e.g. use of dict, list, iterators, subscripts, etc. internals, to aid in debugging in situations where it’s not clear, if these are causing the issue or not.

  • Added support for Fedora 36, which requires some specific linker options, also recognize Fedora based distributions as such.

  • Removed long deprecated option --noinclude-matplotlib from numpy plugin, as it hasn’t had an effect for a long time now.

  • Visual Code: Added extension for editing Jinja2 templates. This one even detects that we are editing C or Python and properly highlights accordingly.


  • Standalone: Major cleanup of the dependency analysis for standalone. There is no longer a distinction between entry points (main binary, extension modules) and DLLs that they depend on. The OS specific parts got broken out into dedicated modules as well and decisions are now taken immediately.

  • Plugins: Split the Yaml package configuration files into 3 files. One contains now Python2 only stdlib configuration, and another one general stdlib.

  • Plugins: Also cleanup the zmq plugin, which was one the last holdouts of now removed plugin method, moving parts to the Yaml configuration. We therefore no longer have considerExtraDlls which used to work on the standalone folder, but instead only plugin code that provides included DLL or binary objects from getExtraDlls which gives Nuitka much needed control over DLL copying. This was a long lasting battle finally won, and will allow many new features to come.

  • UI: Avoid changing whitespace in warnings, where we have intended line breaks, e.g. in case of duplicate DLLs. Went over all warnings and made sure to either avoid new-lines or have them, depending on wanted output.

  • Iterator end check code now uses the same code as rich comparison expressions and can benefit from optimization being done there as well.

  • Solved TODO item about code generation time C types to specify if they have error checking or not, rather than hard coding it.

  • Production of binary helper function set was cleaned up massively, but still needs more work, comparison helper function set was also redesigned.

  • Changing the spelling of our container package to become more clear.

  • Used namedtuple objects for storing used DLL information for more clear code.

  • Added spellchecker ignores for all attribute and argument names of generated fixed attribute nodes.

  • In auto-format make sure the imports float to the top. That very much cleans up generated attribute nodes code, allowing also to combine the many ones it makes, but also cleans up some of our existing code.

  • The package configuration Yaml files are now sorted according to module names. This will help to avoid merge conflicts during hotfixes merge back to develop and automatically group related entries in a sane way.

  • Moved large amounts of code producing implicit imports to Yaml configuration files.

  • Changed the tensorflow plugin to Yaml based configuration, making it a deprecated do nothing plugin, that only remains there for a few releases, to not crash existing build scripts.

  • Lots of spelling cleanups, e.g. renaming nuitka.codegen to nuitka.code_generation for clarity.


  • Added generated test to cover bytes method. This would have found the issue with decode potentially.

  • Enhanced standalone test for ctypes on Linux to actually have something to test.


This release improves on many things at once. A lot of work has been put into polishing the Yaml configuration that now only lacks documentation and examples, such that the community as a whole should become capable of adding missing dependencies, data files, DLLs, and even anti-bloat patches.

Then a lot of new optimization has been done, to close the missing gaps with dict and str methods, but before completing list which is already a work in progress pull request, and bytes, we want to start and generate the node classes that form the link or basis of dedicated nodes. This will be an area to work on more.

The many improvements to existing code helpers, and them being able to pick target types for the arguments of comparisons and binary operations, is a pre-cursor to universal optimization of this kind. What is currently only done for constant values, will in the future be interesting for picking specific C types for use. That will then be a huge difference from what we are doing now, where most things still have to use PyObject * based types.

Scalability has again seen very real improvements, memory usage of Nuitka itself, as well as compile time inside Nuitka are down by a lot for some cases, very noticeably. There is never enough of this, but it appears, in many cases now, large compilations run much faster.

For macOS specifically, the new DLL dependency analysis, is much more capable or resolving conflicts all by itself. Many of the more complex packages with some variants of Python, specifically Anaconda will now be working a lot better.

And then, of course there is the big improvement for Onefile, that allows to use cached paths. This will make it more usable in the general case, e.g. where the firewall of Windows hate binaries that change their path each time they run.

Future directions will aim to make the compilation report more concise, and given reasons and dependencies as they are known on the inside more clearly, such that is can be a major tool for testing, bug reporting and analysis of the compilation result.

Nuitka Release 0.9

This release has a many optimization improvements, and scalability improvements, while also adding new features, with also some important bug fixes.

Bug Fixes

  • Fix, hard module name lookups leaked a reference to that object. Fixed in 0.8.1 already.

  • Python2: Fix, str.decode with errors as the only argument wasn’t working. Fixed in 0.8.1 already.

  • Fix, could corrupt created uncompiled class objects __init__ functions in case of descriptors being used.

  • Standalone: Added support for newer torch. Fixed in 0.8.1 already.

  • Standalone: Added support for newer torchvision. Fixed in 0.8.1 already.

  • Fix, could compile time crash during initial parsing phase on constant dictionary literals with non-hashable keys.

    { {}:1, }
  • Fix, hard imported sub-modules of hard imports were falsely resolved to their parent. Fixed in 0.8.3 already.

    importlib.resources.read_bytes() # gave importlib has no attribute...
  • Windows: Fix, outputs with --force-stdout-spec or --force-stderr-spec were created with the file system encoding on Python3, but they nee to be utf-8.

  • Fix, didn’t allow zero spaces in Nuitka project options, which is not expected.

  • Modules: Fix, the del __file__ in the top level module in module mode caused crashes at run time, when trying to restore the original __file__ value, after the loading CPython corrupted it.

  • Python2.6: Fixes for installations without pkg_resources.

  • Windows: Fix for very old Python 2.6 versions, these didn’t have a language assigned that could be used.

  • Security: Fix for CVE-2022-2054 where environment variables used for transfer of information between Nuitka restarting itself, could be used to execute arbitrary code at compile time.

  • Anaconda: Fix, the torch plugin was not working on Linux due to missing DLL dependencies.

  • Fix, static optimization of importlib.import_module with a package given, for an absolute import was optimized into the wrong import, package was not ignored as it should be.

  • Windows: Installed Python scan could crash on trying installation paths from registry that were manually removed in the mean time, but not through an uninstaller.

  • Standalone: Added missing implicit dependency for pyreadstat because parts of standard library it uses are no more automatically included.

  • Windows: Could still crash when no powershell is available with symlinks, handle this more gracefully.

  • Standalone: Added more missing Plotly dependencies, but more work will be needed to complete this.

  • Standalone: Add missing stdlib dependency on multiprocessing by concurrent.futures.process.

  • Standalone: Fix, implicit dependencies assigned to imageio on PIL plugins should actually be assigned to PIL.Image that actually loads them, so it works outside of imageio too.

New Features

  • UI: Added new option --user-package-configuration-file to allow users to provide extra Yaml configuration files for the Nuitka plugin mechanism to add hidden dependencies, anti-bloat, or data files, for packages. This will be useful for developing PRs to the standard file of Nuitka. Currently the schema is available, but it is not documented very well yet, so not really ready for end users just yet.

  • Standalone: Added new no-qt plugin as an easy way to prevent all of the Qt bindings from being included in a compilation.

  • Include module search path in compilation report.


  • Faster dictionary iteration with our own replacement for PyDict_Next that avoids the DLL call overhead (in case of non-static libpython) and does less unnecessary checks.

  • Added optimization for str.count and str.format methods as well, this should help in some cases with compile time optimization.

  • The node for dict.update with only an iterable argument, but no keyword arguments, was in fact unused due to wrongly generated code. Also the form with no arguments wasn’t yet handled properly.

  • Scalability: Use specialized nodes for pair values, i.e. the representation of x = y in e.g. dictionary creations. With constant keys, and values, these avoid full constant value nodes, and therefore save memory and compile time for a lot of code.

  • Anti-Bloat: Added more scalability work to avoid including modules that make compilation unnecessarily big.

  • Python3.9+: Faster calls in case of mixed code, i.e. compiled code calling uncompiled code.

  • Removing duplicates and non-existent entries from modules search path should improve performance when locating modules.

  • Optimize calls through variables as well. These are needed for the package resource nodes to properly resolve at compile time from their hard imports to the called function.

  • Hard imported names should also be considered very trusted themselves, so they are e.g. also optimized in calls.

  • Anti-Bloat: Avoid more useless imports in Pandas, Numba, Plotly, and other packages, improving the scalability some more.

  • Added dedicated nodes for pkg_resources.require, pkg_resources.get_distribution, importlib.metadata.version, and importlib_metadata.version, so we can use compile time optimization to resolve their argument values where possible.

  • Avoid annotating control flow escape for all release statements. Sometimes we can tell that __del__ will not execute outside code ever, so this then avoids marking values as escaped, and taking the time to do so.

  • Calls of methods through variables on str, dict, bytes that have dedicated nodes are now also optimized through variables.

  • Boolean tests through variables now also are optimized when the original assignment is a compile time constant that is not mutable. This is only basic, but will allow tests on TYPE_CHECKING coming from a from typing import TYPE_CHECKING statement to be optimized, avoiding this overhead.


  • Changed to torch plugin to Yaml based configuration, making it obsolete, it only remains there for a few releases, to not crash existing build scripts.

  • Moved older package specific hacks to the Yaml file. Some of these were from hotfixes where the Yaml file wasn’t yet used by default, but now there is no need for them anymore.

  • Removed most of the pkg-resources plugin work. This is now done during optimization phase and rather than being based on source code matches, it uses actual value tracing, so it immediately covers many more cases.

  • Continued spelling improvements, renaming identifiers used in the source that the cspell based extension doesn’t like. This aims at producing more readable and searchable code.

  • Generated attribute nodes no longer do local imports of the operation nodes they refer to. This also avoids compile time penalties during optimization that are not necessary.

  • Windows: Avoid useless bytecode of inline copy used by Python3 when installing for Python2, this spams just a lot of errors.


  • Removed MSI installers from the download page. The MSI installers are discontinued as Python has deprecated their support for them, as well as Windows 10 is making it harder for users to install them. Using the PyPI installation is recommended on Windows.

  • Merged our Yaml files into one and added schema description, for completion and checking in Visual Code while editing. Also check the schema in check-nuitka-with-yamllint which is now slightly misnamed. The schema is in no way final and will see improvements in future releases.

  • UI: Nicer progress bar layout that avoids flicker when optimizing modules.

  • UI: When linking, output the total number of object files used, to have that knowledge after the progress bar for C compilation is gone.

  • Quality: Auto-format the package configuration Yaml file for anti-bloat, implicit dependencies, etc.

  • GitHub: Point out the commit hook in the PR template.

  • UI: Nicer output in case of no commercial version is used.

  • Updated the MinGW64 winlibs download used on Windows to the latest version based on gcc 11, the gcc 12 is not yet ready.

  • Git: Make sure we are not affected by core.autocrlf setting, as it interferes with auto-format enforcing Unix newlines.

  • Removed the MSI downloads. Windows 10 has made them harder to install and Python itself is discontinuing support for them, while often it was only used by beginners, for which it was not intended.

  • Anaconda: Make it more clear how to install static libpython with precise command.

  • UI: Warn about using module from Debian packages. These can be made non-portable to other OSes. Read more on the info page for detailed information.

  • Quality: The auto-format now floats imports to the top for consistency. With few exceptions, it was already done like this. But it makes things easier for generated code.


  • The reflected test was adapted to preserve PYTHONPATH now that module presence influences optimization.


This release marks a point, that will allow us to open up the compatibility work for implicit dependencies and anti-bloat stuff even further. The Yaml format will need documentation and potentially more refinement, but will open up a future, where latest packages can be supported with just updating this configuration.

The scalability improvements really make a difference for many libraries and are a welcome improvement on both memory usage and compile time. They are achieved by an accord of static optimization of

One optimization aimed at optimizing tuple unpacking, was not finished in time for this release, but will be subject of a future release. It has driven many other improvements though.

Generally, also from the UI, this is a huge step forward. With links to the website for complex topics being started, and the progress bar flicker being removed, the tool has yet again become more user friendly.

Nuitka Release 0.8

This release has a massive amount of bug fixes, builds on existing features, and adds new ones.

Bug Fixes

  • Windows: Fix, need to ignore cases where shorting in path for external use during compilation gives an permission error. Fixed in 0.7.1 already.

  • Compatibility: Added workaround for scipy.stats function copying. Fixed in 0.7.1 already.

  • Windows: Fix, detect ARM64 arch of MSVC properly, such that we can give a proper mismatch for the Python architecture. Fixed in 0.7.1 already.

  • Standalone: Fix, using importlib.metadata module failed to include email from standard library parts no longer included by default. Fixed in 0.7.1 already.

  • macOS: Fix, the dependency parser was using normalized paths where original paths must be used. Fixed in 0.7.1 already.

  • Standalone: Fix, using shiboken6 module (mostly due to PySide6) failed to include argparse from the standard library from standard library parts no longer included by default. Fixed in 0.7.1 already.

  • Onefile: Fix, the detection of a usable Python for compression could crash. Fixed in 0.7.2 already.

  • Onefile: Adding the payload on Windows could run into locks still being held, need to wait in that case. Fixed in 0.7.2 already.

  • Fix, need to include pkg_resources as well, we need it for when we use Jinja2, which is more often now. For Python3 this was fixed in 0.7.3 already. Later a version to use with Python2 was added as well.

  • Release: The wheels built for Nuitka when installed through URLs were not version specific, but due to different inline copies per OS and Python version, they must not be reused. Therefore we now pretend to contain an extension module, which handles that. Fixed in 0.7.3 already.

  • Standalone: Fix, using urllib.requests module failed to include http.client from standard library parts no longer included by default. Fixed in 0.7.3 already. Later http.cookiejar was added too.

  • Standalone: Do not compress MSVC run time library when using upx plugin, that is not going to work. Fixed in 0.7.4 already.

  • Standalone: Fix, on Windows more files should be included for TkInter to work with all software. Fixed in 0.7.5 already.

  • Distutils: Added support for package_dir directive to specify where source code lives. Fixed in 0.7.6 already.

  • Standalone: Fix, using shelve module failed to include dbm from standard library parts no longer included by default. Fixed in 0.7.6 already.

  • Standalone: Added support for arcade data files. Fixed in 0.7.7 already.

  • Standalone: Fix, bytecode demotions should use relative filenames rather than original ones. Fixed in 0.7.7 already.

  • Standalone: Fix, must remove extension module objects from sys.modules before executing an extension module that will create it. This fixes cases of cyclic dependencies from modules loaded by the extension module.

  • Windows: In case of an exception, clcache was itself triggering one during its handling, hiding the real exception behind a TypeError.

  • Windows: Improved clcache locking behavior, avoiding a race. Also increase characters used for key from 2 to 3 chars, making collisions far more rare.

  • Standalone: Added support for persistent package.

  • Standalone: Added support for newer tensorflow package.

  • Module: Fix, need to restore the __file__ and __spec__ values of top level module. It is changed by CPython after import to an incompatible file name, and not our loader, preventing package resources to be found.

  • Standalone: Added support for Crpytodome.Cipher.PKCS1_v1_5.

  • Fix, pkgutil.iter_modules without arguments was not working properly with our meta path based loader.

  • Windows: Fix, could crash on when the Scons report was written due to directories in PATH that failed to encode.

  • Compatibility: Fix, positive divmod and modulo % with negative remainders of positive floats was not correct.

  • Fix, str.encode with only errors value, but default value for encoding was crashing the compilation.

  • Python3.10+: Fix, match statement sliced values must be lists, not tuples.

  • Standalone: Added support for newer glfw and OpenGL packages.

  • Python3: Fix, failed to read bytecode only stdlib files. This affect mostly Fedora Python which does this for encodings.

  • Python3.5+: Fix, two phase loading of modules could release it immediately.

  • Standalone: Added missing dependency for pydantic.

  • Fix, the str.split rejected default sep value with only maxsplit given as a keyword argument.

  • Standalone: Added missing dependency of wsgiref module.

  • Standalone: Added support for falcon module.

  • Standalone: Added support for eliot module.

  • Fix, need to mark assigned from variables as escaped. Without it, some aliased loop variables could be misunderstood and falsely statically optimized.

  • Standalone: Added support for newer uvicorn package.

  • Standalone: Added data files for the accessible_output2, babel, frozendict, and sound_lib package.

  • Standalone: Added support for newer sklearn package.

  • Standalone: Added support for tkinterdnd2 package.

  • Python3.7+: Fix, the error message wasn’t fully compatible for unsubscriptable type exception messages.

  • Standalone: Fix, idlelib from stdlib was always ignored.

  • Python3.4+: Fix, the __spec__.origin as produced by find_spec of our meta path based loader, didn’t have the correct origin attribute value.

  • Standalone: Disable QtPDF plugin of PySide 6.3.0, because it’s failing dependency checks. On macOS this was blocking, we will change it to detection if that is necessary in a future release.

  • Standalone: Added support for orderedmultidict.

  • Standalone: Added support for clr module.

  • Standalone: Added support for newer cv2 package.

New Features

  • Added new option --module-name-choice to select what value __name__ and __package__ are going to be. With --module-name-choice=runtime (default for --module mode), the created module uses the parent package to deduce the value of __package__, to be fully compatible. The value --module-name-choice=original (default for other modes) allows for more static optimization to happen.

  • Added support for get_resource_reader to our meta path based loader. This allows to avoid useless temporary files in case importlib.resources.path is used, due to a bad interaction with the fallback implementation used without it.

  • Added support for --force-stdout-spec```and ``--force-stderr-spec on all platforms, this was previously limited to Windows.

  • Added support for requiring and suggesting modes. In part this was added to 0.7.3 already, and is used e.g. to enforce that on macOS the wx will only work as a GUI program and crash unless --disable-console is specified. These will warn the user or outright error the compilation if something is known to be needed or useful.

  • Debian: Detect version information for “Debian Sid”. Added in 0.7.4 already, and also improved how Debian/Ubuntu versions are output.

  • Added new option --noinclude-data-files to instruct Nuitka to not include data files matching patterns given. Also attached loggers and tags to included data file and include them in the compilation report.

  • Distutils: When using pyproject.toml without so far it was not possible to pass arguments. This is now possible by adding a section like this.

    # options without an argument are passed as boolean value
    show-scons = true
    # options with single values, e.g. enable a plugin of Nuitka
    enable-plugin = "pyside2"
    # options with several values, e.g. avoiding including modules, accepts
    # list argument.
    nofollow-import-to = ["*.tests", "*.distutils"]

    The option names are the same, but without leading dashes. Lists are only needed when passing multiple values with the same option.

  • macOS: Add support for specifying signing identity with --macos-sign-identity and access to protected resources --macos-app-protected-resource.

  • Included data files are now reported in the compilation report XML as well.

  • Accept absolute paths for searching paths of binaries. This allows e.g. the upx plugin to accept both a folder path and the full path including the binary name to work when you specify the binary location with --upx-binary making it more user friendly.

  • Python3.10: Added support for positional matching of classes, so far only keyword matching was working.

  • Added support for path spec values %CACHE_DIR, %COMPANY%, %PRODUCT%, %VERSION%, and %HOME in preparation of onefile once again being able to be cached and not unpacked repeatedly for each execution.

  • Standalone: Detect missing tk-inter plugin at run time. When TCL fails to load, it then outputs a more helpful error. This ought to be done for all plugins, where it’s not clear if they are needed.

  • Anti-Bloat: Added support for plain replacements in the anti-bloat.yml file. Before with replacement`, the new value had to be produced by an eval, which makes for less readable values due to extra quoting. for plain values.


  • Python3.10+: Added support for ordered-set PyPI package to speed up compilation on these versions too, adding a warning if no accelerated form of OrderedSet is used, but believed to be usable.

  • Optimization: Added bytes.decode operations. This is only a start and we needed this for internal usage, more should follow later.

  • Much more anti-bloat work was added. Avoiding ipython, unittest, and sometimes even doctest usage for some more packages.

  • The ccache was not always used, sometimes it believed to catch a potential race, that we need to tell it to ignore. This will speed up re-compilation of the C side in many cases.

  • Do not compile the meta path based loader separate, which allows us to not expose functions and values only used by it. Also spares the C compiler one file.

  • Added various dedicated nodes for querying package resources data, e.g. pkgutil.get_data. This will make it easier to detect cases of missing data files in the future.

  • Added more hard imports, some of which help scalability in the compilation, because these are then known to exist in standalone mode, others are used for package resource specific operations.

  • Onefile: Releasing decompression buffers avoiding unnecessary high memory usage of bootstrap binary.

  • Standalone: Avoid proving directories with no DLLs (e.g. from packages) towards ldd, this should avoid exceeding command line limits.

  • For clcache remove writing of the stats file before Scons has completed, which avoids IO and locking churn.

  • Standalone: Avoid including wsgiref from stdlib by default.


  • Removed references to chrpath and dead code around it, it was still listed as a dependency, although we stopped using it a while ago.

  • Removed uses of anti-bloat in examples and tests, it is now enabled by default.

  • Made standard plugin file naming consistent, their name should be *

  • Cleaned up tensorflow plugin. The source modification was moved to anti-bloat where it is easy to do. The implicit dependencies are now in the config file of implicit-imports plugin.

  • Massive cleanups of data file handling in plugins. Adding methods for producing the now required objects.

  • The Scons file handling got further cleaned up and unified, doing more things in common code.

  • Avoid #ifdefs usages with new helper function Nuitka_String_FromFormat that implies them for more readable code.

  • Split the allowance check from the encountering. Allow plugins and options all to say if an import should be followed, and only when that is decided, to complain about it. Previously the attempt was causing an error, even if another plugin were to decide against it later.

  • Python2.6: Avoid warnings from MSVC for out specialized long code. In testing it worked correctly, but this is more explicit and doesn’t rely on C implementation specific behavior, although it appears to be universal.


  • UI: Warning tests are now wrapped to multiple lines if necessary. That makes it more accessible for larger messages that contain more guiding information.

  • Documented how to use local Nuitka checkout with pyproject.toml files, this makes debugging Nuitka straightforward in these setups.

  • Added instructions on how to pass extra C and linker flags and to the User Manual.

  • Made our auto-format usable for the Nuitka website code too.

  • Removed dependencies on chrpath and the now dead code that would use it, we are happy with patchelf.

  • Updated to latest versions of requirements for development, esp. black and pylint.

  • Renamed --macos-onefile-icon to --macos-app-icon because that is what it is really used for.

  • Unified how dependencies are installed in GitHub actions.

  • Updated man page contents for option name changes from last releases.

  • Updated the MinGW64 winlibs download used on Windows to the latest version.

  • Updated the ccache binary used on Windows with MinGW64. This is in preparation of using it potentially for MSVC as well.

  • Updated Visual Code C config to use Python3.10 and MSVC 2022 include paths.


  • Better outputs from standalone library compilation test, esp. when finding a problem, present the script to reproduce it immediately.

  • Enhanced generated tests to cover str methods to use keyword arguments.

  • Added automatic execution of pyproject.toml driven test case.

  • Enhanced output in case of optimization test failures, dumping what value is there that has not become a compile time constant.


This release has seen a lot of consolidation. The plugins layer for data files is now all powerful, allowing much nicer handling of them by the plugins, they are better reported in normal output, and they are also part of the report file that Nuitka can create. You may now also inhibit their inclusion from the command line, if you decide otherwise.

The pyproject.toml now supporting Nuitka arguments is closing an important gap.

Generally many features got more polished, e.g. non-automatic inclusion of stdlib modules has most problems fixed up.

An important area of improvement, are the hard imports. These will be used to replace the source based resolution of package requirements with ones that are proper nodes in the tree. Getting these hard imports to still retain full compatibility with existing imports, that are more or less __import__ uses only, was revealing quite a bit of technical debt, that has been addressed with this release.

For onefile, the cached mode is being prepared with the variables added, but will only be in a later release.

Also a bunch of new or upgraded packages are working now, and the push for anti-bloat work has increased, making many compilations even more lean, but scalability is still an issue.

Nuitka Release 0.7

This release is massively improving macOS support, esp. for M1 and the latest OS releases, but it also has massive improvements for usability and bug fixes in all areas.

Bug Fixes

  • Fix, set creation wasn’t annotating its possible exception exit from hashing values and is not as free of side effects as list and tuple creations are. Fixed in already.

  • Windows: Fix, --experimental option values got lost for the C compilation when switching from MSVC to MinGW64, making them have no effect. Fixed in already.

  • Windows: Fix, Clang from MinGW64 doesn’t support LTO at this time, therefore default to no for it. Fixed in already.

  • Debian: Fix, failed to detect Debian unstable as suitable for linking, it doesn’t have the release number. Fixed in already.

  • Standalone: Added data files for pygsheets package. Fixed in already.

  • Fix, paths from plugin related file paths need to be made absolute before used internally, otherwise the cache can fail to deduplicate them. Fixed in already.

  • Python3: With gcc before version 5, e.g. on CentOS 7, where we switch to using g++ instead, the gcc version checks could crash. Fixed in already.

  • Windows: Disable MinGW64 wildcard expansion for command line arguments. This was breaking command lines with arguments like --filename *.txt, which under cmd.exe are left alone by the shell, and are to be expanded by the program. Fixed in already.

  • Standalone: Added missing implicit dependency needed for --follow-stdlib with Python for some uses of the locale module. Fixed in already.

  • Standalone: Added workarounds for newest numpy that wants to set __code__ objects and required improvements for macOS library handling. Fixed in already.

  • Windows: Caching of DLL dependencies for the main programs was not really working, requiring to detect them anew for every standalone compilation for no good reason. Fixed in already.

  • Windows: Fix, CTRL-C from a terminal was not propagated to child processes on Windows. Fixed in already.

  • Standalone: With certifi and Python3.10 the importlib.resource could trigger Virus scanner inflicted file access errors. Fixed in already.

  • Python3.10: Reverted error back iteration past end of generator change for Python 3.10.2 or higher to become compatible with that too. Fixed in already.

  • Standalone: Added support for anyio and by proxy for Solana. Fixed in already.

  • Fix, compilation with resource mode incbin and --debugger was not working together. Fixed in already.

  • Fix, format optimization of known str objects was not properly annotating an exception exit when being optimized away, causing consistency checks to complain. Fixed in already.

  • Windows: Fix, clcache didn’t work for non-standard encoding source paths due to using th direct mode, where wrong filenames are output by MSVC. Fixed in already.

  • Windows: Fix, ccache cannot handle source code paths for non-standard encoding source paths. Fixed in already.

  • Python2.6: Fix, calls to iteritems and iterkeys on known dictionary values could give wrong values. Fixed in already.

  • Fix, the value of __module__ if set by the metaclass was overwritten when creating types. Fixed in already.

  • Plugins: Add support for the latest version of pkg_resources that has “vendored” even more packages. Fixed in already.

  • Onefile: The onefile binary was locked during run time and could not be renamed, preventing in-place updates. This has been resolved and now on Windows, the standard trick for updating a running binary of renaming it, then placing the new file works.

  • Fix, wasn’t checking the zstandard version and as a result could crash if too old versions of it. This is now checked.

  • macOS: Large amounts of bug fixes for the dependency scanner. It got cleaned up and now handles many more cases correctly.

  • Windows: Fix, was not properly detecting wrong ClangCL architecture mismatch with the Python architecture. This could result in strange errors during C compilation in this setup.

  • Standalone: Added implicit dependencies for the asyncpg module.

  • Linux: Detect Debian or Ubuntu base and distribution name more reliably. This helps esp. with static libpython optimization being recognized automatically.

New Features

  • We now disallow options that take arguments to be provided without using =.

  • Previously --lto no worked just as well as --lto=no did. And that was the cause of problems when --lto first became a choice.

    Recently similar, but worse problems were observed, where e.g. --include-module could swallow trailing other arguments when users forgot to specify the name by accident. Therefore this style of giving options is now explicitly rejected.

  • Compiled types of Nuitka now inherit from uncompiled types. This should allow easier and more complete compatibility, making even code in extension modules that uses PyObject_IsInstance work, e.g. pydantic.

  • macOS: Added signing of application bundles and standalone binaries for deployment to newer macOS platforms and esp. M1 where these are mandatory for execution.

  • macOS: Added support for selecting the single macOS target arch to create a binary for. The universal architecture is not yet supported though, but will be added in a future release.

  • Added support for compression in onefile mode through the use of an other Python installation, that has the zstandard module installed. With this it will work with 2.6 or higher, but require a 3.5 or higher Python with it installed in either PATH or on Windows in the registry alternatively.

  • Added UPX plugin to compress created extension modules and binaries and for standalone mode, the included DLLs. For onefile, the compression is not useful since it has the payload already compressed.

  • Added a more explicit way to list usable MSVC versions with --msvc=list rather than requiring an invalid value. Check values given in the same way that Scons will do.

  • Added support for --python-flag=-u which disabled outputs buffers, so that these outputs are written immediately.

  • Plugins: Always on plugins now can have command line options. We want this for the anti-bloat plugin that is enabled by default in this release.

  • Plugins: Added ability for plugin to provide fake dependencies for a module. We want the this for the multiprocessing plugin, that is now enabled by default in this release too.

  • Plugins: Added ability for plugins to modify DLLs after copy for standalone. We will be using this in the new upx plugin.

  • Added retry for file copies that fail due to still running program. This can happen on Windows with DLLs in standalone mode. For interactive compilation, this allows a retry to happen after prompting the user.

  • UI: Added ability to list MSVC versions with --msvc=list, and detect illegal values given to --msvc= before Scons sees them, it also crashes with a relative unhelpful error message.

  • UI: When linking, close the C compilation progress bar and state that that linking is going on. For some very large LTO compilations, it was otherwise at 100% and still taking a long time, confusing users.

  • Plugins: Added new plugin that is designed to handle DLL dependencies through a configuration file that can both handle filename patterns as well as code provided DLL locations.

  • Optimization: Exclude parts of the standard library by default. This allows for much smaller standalone distributions on modules, that can be expected to never be an implicit dependency of anything, e.g. argparse or pydoc.


  • Standalone: Do not include encodings.bz2_codec and encodings.idna anymore, these are not file system encodings, but require extension modules.

  • Make sure we use proper (void) arguments for C functions without arguments, as for C functions, that makes a real difference, they are variable args functions and more expensive to call otherwise.

  • For standalone, default to using --python-flag=no_site to avoid the overhead that the typically unused site module incurs. It often includes large parts of the standard library, which we now want to be more selective about. There is new Python flag added called --python-flag=site that restores the inclusion of site module.

  • Standalone: Exclude non-critical codec modules from being technical, i.e. have to be available at program startup. This removes the need for e.g. bz2 related extension modules previously included.

  • In reformulations, use dictionary methods directly, we have since introduced dictionary specific methods, and avoid the unnecessary churn during optimization.

  • The complex call helper could trigger unnecessary passes in some cases. The pure functions were immediately optimized, but usages in other modules inside loops sometimes left them in incomplete states.

  • Windows: Avoid repeated hashing of the same files over and over for clcache.

  • Cache dependencies of bytecode demoted modules in first compile and reuse that information in subsequent compilations.

  • Linux: Added option for switching compression method for onefile created with AppImage. The default is also now gzip and not xz which has been observed to cause much slower startup for little size gains.

  • Standalone: For failed relative imports, during compiled time absolute imports were attempted still and included if successful, the imports would not be use them at run time, but lead to more modules being included than necessary.


  • There is now a Discord server for Nuitka community where you can hang out with the developers and ask questions. It is mirrored with the Gitter community chat, but offers more features.

  • The anti-bloat is now on by default. It helps scalability by changing popular packages to not provide test frameworks, installation tools etc. in the resulting binary. This oftentimes reduces the compilation by thousands of modules.

  • Also the multiprocessing plugin is now on by default. Detecting its need automatically removes a source of problems for first time users, that didn’t know to enable it, but had all kinds of strange crashes from multiprocessing malfunctioning. This should enhance the out of the box experience by a lot.

  • With this release, the version numbering scheme will be changed. For a long time we have used 4 digits, where one is a leading zero. That was initially done to indicate that it’s not yet ready. However, that is just untrue these days. Therefore, we switch to 3 digits, and a first hotfix with now be 0.7.1 rather than, which is too long.

    It has been observed that people disregard differences in the third digit, but actually for Nuitka these have oftentimes been very important updates. This change is to rectify it, and a new release will be 0.8, and there will be a 1.0 release after 0.9.

  • Added a new section to User Manual that explains how to manually load files, such that it is cleaner and compatible code. Using paths relative to current directory is not the right way, but there are nice helpers that make it very simple and correct with all kinds of contexts.

  • Report the MSVC version in Scons output during compilation. The 2022 version is required, but we support everything back to 2008, to work on very old systems as well. This will help identifying differences that arise from there.

  • Quality: Find Clang format from MSVC 2022 too. We use in auto format of Nuitka source code, but need to also search that as a new path.

  • Added a spellchecker extension for Visual Code, resulting in many spelling fixes in all kinds of documentation and code. This finds more things than codespell, but also has a lot of false alarms.

  • Check value of --onefile-tempdir-spec for typical user errors. It cannot be . as that would require to overwrite the onefile binary on Windows, and will generally behave very confusing. Warn about absolute or relative paths going outside of where the binary lives. Can be useful in controlled setups, but not generally. Also warn about using no variables, making non-unique paths.

  • macOS: Flavor detection was largely expanded. The Apple flavor is recognized on more systems. Homebrew was newly added, and we actually can detect CPython reliably as a first.

  • Added a tool from leo project to create better .pyi files for modules. We will make use of it in the future to enhance the files created by Nuitka to not only contain hidden dependencies, but optionally also module signatures.

  • Plugins: Clearer information from pyside2 that patched wheels might be mandatory and workarounds only patches cannot be done for older Python.

  • Added progress bars for DLL dependency detection and DLL copying for standalone. These both can end up using take a fair bit of time depending on project size, and it’s nice to know what’s going on.

  • macOS: Added support for using both --onefile and --macos-create-app-bundle as it is needed for PySide2 due to issues with signing code now.

  • Added warning when attempting to include extension modules in an accelerated compilation.

  • Modules: Catch the user error of following all imports when creating a module. This is very unlikely to produce usable results.

  • Start integrating Sourcery for improved Nuitka code. It will comment on PRs and automatically improve Nuitka code as we develop it.

  • Debugging: Added command line tool find-module that outputs how Nuitka locates a module in the Python environment it’s ran with. That removes the need to use Python prompt to dump __file__ of imported modules. Some modules even hide parts of their namespace actively during run-time, the tool will not be affected by that.


  • Refactored Python scan previously used for Scons usage on versions that need to run in with another Python to be more generally usable.

  • Use explicit nuitka.utils.Hashing module that allows the core to perform these operations with simpler code.

  • macOS: Use isPathBelow for checking if something is a system library for enhanced robustness and code clarity.

  • macOS: Make sure to use our proper error checking wrappers for command execution when using tools like otool or codesign.

  • Standalone: Avoid a temporary file with a script during technical import detection. These have been observed to potentially become corrupted, and this avoids any chance of that happening, while also being simpler code.

  • Avoid naming things shlib and call them extension instead. Inspired by the spell checker disliking the former term, which is also less precise.

  • Removed the dead architecture selection option for Windows, it was unused for a long time.

  • Moved Windows SxS handling of DLLs to a more general place where also macOS specific tasks are applied, to host standard modification of DLLs during their copying.


  • Better matching of relative filenames for search modes of the individual test suite runners.

  • Debugger outputs on segfaults were no longer visible and have been restored.


This release is tremendous progress for macOS. Finally biting the bullet and paying obscene amounts of money to rent an M1 machine, it was possible to enhance the support for this platform. Currently typical packages for macOS are being made compatible as well, so it can now be expected to perform equally well.

On the quality side, the spell checker has had some positive effects, finding typos and generally misspelled code, that codespell does not, due to it being very conservative.

The trend to enhance plugins has continued. The copying of DLLs is very nearly finalized. Making more plugins enabled by default is seeing a lot of progress, with 2 important ones addressed.

Work on the size of distributions has seen a lot of positive results, in that now standalone distributions are often very minimal, with many extension modules from standard library no longer being present.

Nuitka Release 0.6.19

This release adds support for 3.10 while also adding very many new optimization, and doing a lot of bug fixes.

Bug Fixes

  • Calls to importlib.import_module with expressions that need releases, i.e. are not constant values, could crash the compilation. Fixed in already.

  • After a fix for the previous release, modules that fail to import are attempted again when another import is executed. However, during this initialization for top level module in --module mode, this was was done repeatedly, and could cause issues. Fixed in already.

  • Standalone: Ignore warning given by patchelf on Linux with at least newer OpenSUSE. Fixed in already.

  • Fix, need to avoid computing large values out of << operation as well. Fixed in already.

    # This large value was computed at run time and then if used, also
    # converted to a string and potentially hashed, taking a long time.
    1 << sys.maxint
  • Standalone: Ignore warning given by patchelf on Linux about a workaround being applied.

  • Fix, calls to importlib.import_module were not correctly creating code for dynamic argument values that need to be released, causing the compilation to report the error. Fixed in already.

  • MSYS2: Fix, the console scripts are actually good for it as opposed to CPython, and the batch scripts should not be installed. Fixed in already.

  • Setuptools: Added support older version of setuptools in meta build integration of Nuitka.

  • Fix, calls to importlib.import_module with 2 arguments that are dynamic, were not working at all. Fixed in already.

  • Windows: Compiling with MinGW64 without ccache was not working due to issues in Scons. Fixed in already.

  • Fix, the repr built-in was falsely annotated as producing a str value, but it can be also derived or unicode in Python2.

  • Fix, attribute nodes were not considering the value they are looking up on. Now that more values will know to have the attributes, that was causing errors. Fixed in already.

  • Fix, left shifting can also produce large values and needs to be avoided in that case, similar to what we do for multiplications already. Fixed in already.

  • UI: The new option --disable-ccache didn’t really have the intended effect. Fixed in already.

  • UI: The progress bar was causing tearing and corrupted outputs, when outputs were made, now using proper tqdm API for doing it, this has been solved. Fixed in already.

  • Fix, the constant value sys.version_info didn’t yet have support for its type to be also a compile time constant in e.g. tuples. Fixed in already.

  • Onefile: Assertions were not disabled, and on Windows with MinGW64 this lead to including the C filenames of the zstd inline copy files and obviously less optimal code. Fixed in already.

  • Standalone: Added support for bottle.ext loading extensions to resolve at compile time. Fixed in already.

  • Standalone: Added support for seedir required data file. Fixed in already.

  • MSYS2: Failed to link when using the static libpython, which is also now the default for MSYS2. Fixed in already.

  • Python3.6+: Fix, the intended finalizer of compiled asyncgen was not present and in fact associated to help type. This could have caused corruption, but that was also very unlikely. Fixed in already.

  • Python3: Fix, need to set __file__ before executing modules, as some modules, e.g. newer PyWin32 use them to locate things during their initialization already.

  • Standalone: Handle all PyWin32 modules that need the special DLLs and not just a few.

  • Fix, some .pth files create module namespaces with __path__ that does not exist, ignore these in module importing.

  • Python2.6-3.4: Fix, modules with an error could use their module name after it was released.

  • Distutils: When providing arguments, the method suggested in the docs is not compatible with all other systems, e.g. not setuptools_rust for which a two elements tuple form needs to be used for values. Added support for that and documented its use as well in the User Manual.

  • Python3.7+: Do no longer allow deleting cell values, this can lead to corruption and should be avoided, it seems unlikely outside of tests anyway.

  • Standalone: Added support for more ciphers and hashes with pycryptodome and pycryptodomex, while also only including Ciphers when needed.

  • Distutils: Was not including modules or packages only referenced in the entry point definition, but not in the list of packages. That is not compatible and has been fixed.

  • Fix, must not expose the constants blob from extension modules, as loading these into a compiled binary can cause issues in this case.

  • Standalone: Added support for including OpenGL and SSL libraries with PySide2 and PySide6 packages.

  • Windows: Fix, the cmd files created for uninstalled Python and accelerated programs to find the Python installation were not passing command line arguments.

  • Windows: Executing modules with --run was not working properly due to missing escaping of file paths.

  • Fix, parsing .pyi files that make relative imports was not resolving them correctly.

  • Python3: Fix, when disabling the console on Windows, make sure the file handles still work and are not None.

  • Windows: Fix, need to claim all OS versions of Windows as supported, otherwise e.g. high DPI features are not available.

New Features

  • Programs that are to be executed with the -m flag, can now be compiled with --python-flag=-m and will then behave in a compatible way, i.e. load the containing package first, and have a proper __package__ value at run time.

  • We now can write XML reports with information about the compilation. This is initially for use in PGO tests, to decide if the expected forms of inclusions have happened and should grow into a proper reporting tool over time. At this point, the report is not very useful yet.

  • Added support for Python 3.10, only match statements are not completely supported. Variations with | matches that also assign are not allowed currently.

  • Windows: Allow using --clang with --mingw64 to e.g. use the clang.exe that is contained in the Nuitka automatic download rather than gcc.exe.

  • Added support for Kivy. Works through a plugin that is automatically enabled and needs no other inputs, detecting everything from using Kivy at compile time.

  • Added initial support for Haiku OS, a clone of BeOS with a few differences in their Python installation.

  • Added experimental plugin trio that works around issues with that package.


  • Also trust hard imports made on the module level in function level code, this unlocks many more static optimization e.g. with sys.version_info when the import and the use are not on the same level.

  • For the built-in type method calls with generic implementation, we now do faster method descriptor calls. These avoid creating a temporary PyCFunction object, that the normal call slot would, this should make these calls faster. Checking them for compiled function, etc. was only wasteful, so this makes it more direct.

  • Loop and normal merge traces were keeping assignments made before the loop or inside a branch, that was otherwise unused alive. This should enable more optimization for code with branches and loops. Also unused loop traces are now recognized and removed as well.

  • Avoiding merges of escaped traces with the unescaped trace, there is no point in them. This was actually happening a lot and should mean a scalability improvement and unlock new optimization as well.

  • Avoid escaping un-init traces. Unset values need not be considered as potentially modified as that cannot be done.

  • The str shape is now detected through variables, this enables many optimization on the function level.

  • Added many str operation nodes.

    These are specifically all methods with no arguments, as these are very generic to add, introduced a base class for them, where we know they all have no effect or raise, as these functions are all guaranteed to succeed and can be served by a common base class.

    This covers the str.capitalize, str.upper, str.lower, str.swapcase, str.title, str.isalnum, str.isalpha, str.isdigit, str.islower, str.isupper, str.isspace, and str.istitle functions.

    For static optimization str.find and str.rfind were added, as they are e.g. used in a sys.version.find(...) style in the os module, helping to decide to not consider OS/2 only modules.

    Then, support for str.index and str.rindex was added, as these are very similar to str.find forms, only that these may raise an exception.

    Also add support for str.split and str.rsplit which will be used sometimes for code needed to be compile time computed, to e.g. detect imports.

    Same goes for endswith and startswith, the later is e.g. popular with sys.platform checks, and can remove a lot of code from compilation with them now being decided at compile time.


    A few str methods are still missing, with time we will achieve all of them, but this will take time.

  • Added trust for sys.builtin_module_names as well. The os module is using it to make platform determinations.

  • When writing constant values, esp. tuple, list, or dict values, an encoding of “last value” has been added, avoiding the need to repeat the same value again, making many values more compact.

  • When starting Nuitka, it usually restarts itself with information collected in a mode without the site module loaded, and with hash randomization disabled, for deterministic behaviour. There is a option to prevent this from happening, where the goal is to avoid it, e.g. in testing, say for the coverage taking, but that meant to parse the options twice, which also loads a lot of code.

    Now only a minimal amount of code is used, and the options are parsed only on the restart, and then an error is raised when it notices, it was not allowed to do so. This also makes code a lot cleaner.

  • Specialized comparison code for Python2 long and Python3 int code, making these operations much faster to use.

  • Specialized comparison code for Python2 unicode and Python3 str code, making these operations much faster to use, currently only == and != are fully accelerated, the other comparisons will follow.

  • Enable static libpython with Python3 Debian packages too. As with Python2, this will improve the performance of the created binary a lot and reduce size for standalone distribution.

  • Comparisons with in and not in also consider value traces and go through variables as well where possible. So far only the rich comparisons and is and is not did that.

  • Create fixed import nodes in re-formulations rather than __import__ nodes, avoiding later optimization doing that, and of course that’s simpler code too.

  • Python 3.10: Added support for union types as compiled time constants.

  • Modules are now fully optimized before considering which modules they are in turn using, this avoids temporary dependencies, that later turn out unused, and can shorten the compilation in some cases by a lot of time.

  • On platforms without a static link library, in LTO mode, and with gcc, we can use the -O3 mode, which doesn’t work for libpython, but that’s not used there. This also includes fake static libpython, as used by MinGW64 and Anaconda on Windows.

  • The anti-bloat plugin now also handles newer sklearn and knows more about the standard library, and its runners which it will exclude from compilation if use for it. Currently that is not the default, but it should become that.


  • Migrated the Nuitka blog from Nikola to Sphinx based ABlog and made the whole site render with Sphinx, making it a lot more usable.

  • Added a small presentation about Nuitka on the Download page, to make sure people are aware of core features.

  • The gi plugin is now always on. The copying of the typelib when gi is imported is harmless and people can disable the plugin if that’s not needed.

  • The matplotlib plugin is new and also always on. It previously was part of the numpy plugin, which is doing too many unrelated things. Moving this one out is part of a plan to split it up and have it on by default without causing issues.

  • MSYS2: Detecting MinGW and POSIX flavors of this Python. For the MinGW flavor of MSYS2, the option --mingw64 is now the default, before it could attempt to use MSVC, which is not going to work for it. And also the Tcl and Tk installations of it are being detected automatically for the tk-inter plugin.

  • Added Windows version to Nuitka version output, so we have this for bug reports.

  • User Manual: Added example explaining how to access values from your code in Nuitka project options.

  • UI: For Python flavors where we expect a static libpython, the error message will now point out how to achieve it for each flavor.

  • UI: Disable progress bar when --show-scons is used, it makes capturing the output from the terminal only harder.

  • UI: Catch error of specifying both --msvc= and --mingw64 options.

  • Distutils: Improved error messages when using setuptools or build integration and failing to provide packages to compile.

  • Plugins: Removed now unused feature to rename modules on import, as it was only making the code more complex, while being no more needed after recently adding a place for meta path based importers to be accounted for.

  • Twitter: Use embedded Tweet in Credits, and regular follow button in User Manual.

  • Warnings about imports not done, are now only given when optimization can not remove the usage, and no options related to following have been given.

  • Added Windows version to --version output of Nuitka. This is to more clearly recognize Windows 10 from Windows 11 report, and also the odd Windows 7 report, where tool chain will be different.

  • In Visual Code, the default Python used is now 3.9 in the “Linux” C configuration. This matches Debian Bullseye.

  • Nicer outputs from check mode of the auto-format as run for CI testing, displays problematic files more clearly.

  • Remove broken links to old bug tracker that is no longer online from the Changelog.

  • UI: When hitting CTRL-C during initial technical import detection, no longer ask to submit a bug report with the exception stack, instead exit cleanly.

  • Windows: Enable LTO mode for MinGW64 and other gcc by default. We require a version that can do it, so take advantage of that.

  • For cases, where code generation of a module takes long, make sure its name is output when CTRL-C is hit.

  • Windows: Splash screen only works with MSVC, added error indicator for MinGW64 that states that and asks for porting help.


  • Generate all existing C code for generic builtin type method calls automatically, and use those for method attribute lookups, making it easier to add more.

  • Changed TkInter module to data file providing interface, yielding the 2 directories in question, with a filter for demos.

  • The importing code got a major overhaul and no longer works with relative filenames, or filenames combined with package names, and module names, but always only with module names and absolute filenames. This cleans up some of the oldest and most complex code in Nuitka, that had grown to address various requirements discovered over time.

  • Major cleanup of Jinja2 template organisation.

    Renamed all C templates from .j2 to .c.j2 for clarity, this was not done fully consistent before. Also move all C templates to nuitka.codegen package data, it will be confusing to make a difference between ones used during compile time and for the static generation, and the lines are going to become blurry.

    Added Jinja2 new macro CHECK_OBJECTS to avoid branches on argument count in the call code templates. More of these things should be added.

    Cleanup of code that generates header declarations, there was some duplication going on, that made it hard to generate consistent code.

  • Removed nuitka.finalizatios.FinalizationBase, we only have one final visitor that does everything, and that of course makes a lot of sense for its performance.

  • Major cleanup of the Scons C compiler configuration setup. Moved things to the dedicate function, and harmonized it more.

  • Resolved deprecation warnings given by with --python-debug for Nuitka.


  • Started test suite for Python PGO, not yet completely working though, it’s not yet doing what is needed though.

  • Added generated test that exercises str methods in multiple variations.

  • Revived reflected test suite, that had been removed, because of Nuitka special needs. This one is not yet passing again though, due to a few details not yet being as compatible as needed.

  • Added test suite for CPython 3.10 and enable execution of tests with this version on GitHub actions.


This release is another big step forward.

The amount of optimization added is again very large, some of which yet again unlocks more static optimization of module imports, that previously would have to be considered implicit. Now analyzing these on the function level as well, we can start searching for cases, where it could be done, but is not done yet.

After starting with dict, method optimization has focused on str which is esp. important for static optimization of imports. The next goal will here be to cover list which are important for run time performance and currently not yet optimized. Future releases will progress there, and also add more types.

The C type specialization for Python3 has finally progressed, such that it is also covering the long and unicode and as such not limited to Python2 as much. The focus now needs to turn back to not working with PyObject * for these types, but e.g. with += 1 to make it directly work with CLONG rather than LONG for which structural changes in code generation will be needed.

For scalability, the anti-bloat work has not yet progressed as much as to be able to enable it by default. It needs to be more possible to disable it where it causes problems, e.g. when somebody really wants to include pytest and test frameworks generally, that’s something that needs to be doable. Compiling without anti-bloat plugin is something that is immediately noticeable in exploding module amounts. It is very urgently recommended to enable it for your compilations.

The support for Windows has been further refined, actually fixing a few important issues, esp. for the Qt bindings too.

This release adds support for 3.10 outside of very special match statements, bringing Nuitka back to where it works great with recent Python. Unfortunately orderedset is not available for it yet, which means it will be slower than 3.9 during compilation.

Overall, Nuitka is closing many open lines of action with this. The setuptools support has yet again improved and at this point should be very good.

Nuitka Release 0.6.18

This release has a focus on new features of all kinds, and then also new kinds of performance improvements, some of which enable static optimization of what normally would be dynamic imports, while also polishing plugins and adding also many new features and a huge amount of organisational changes.

Bug Fixes

  • Python3.6+: Fixes to asyncgen, need to raise StopAsyncIteration rather than StopIteration in some situations to be fully compatible.

  • Onefile: Fix, LTO mode was always enabled for onefile compilation, but not all compilers support it yet, e.g. MinGW64 did not. Fixed in already.

  • Fix, type calls with 3 arguments didn’t annotate their potential exception exit. Fixed in already.

  • Fix, trusted module constants were not working properly in all cases. Fixed in already.

  • Fix, pkg-resources exiting with error at compile time for unresolved requirements in compiled code, but these can of course still be optional, i.e. that code would never run. Instead give only a warning, and run time fail on these. Fixed in already.

  • Standalone: Prevent the inclusion of drm libraries on Linux, they have to come from the target OS at run time. Fixed in already.

  • Standalone: Added missing implicit dependency for ipcqueue module. Fixed in already.

  • Fix, Qt webengine support for everything but PySide2 wasn’t working properly. Partially fixed in already.

  • Windows: Fix, bootstrap splash screen code for Windows was missing in release packages. Fixed in already.

  • Fix, could crash on known implicit data directories not present. Fixed in already.

  • macOS: Disable download of ccache binary for M1 architecture and systems before macOS 10.14 as it doesn’t work on these. Fixed in already.

  • Standalone: The pendulum.locals handling for Python 3.6 was regressed. Fixed in already.

  • Onefile: Make sure the child process is cleaned up even after its successful exit. Fixed in already.

  • Standalone: Added support for xmlschema. Fixed in already.

  • Standalone: Added support for curses on Windows. Fixed in already.

  • Standalone: Added support for coincurve module. Fixed in already.

  • Python3.4+: Up until Python3.7 inclusive, a workaround for stream encoding (was ASCII), causing crashes on output of non-ASCII, other Python versions are not affected. Fixed in already.

  • Python2: Workaround for LTO error messages from older gcc versions. Fixed in already.

  • Standalone: Added support for win32print. Fixed in already.

  • Fix, need to prevent usage of static libpython in module mode or else on some Python versions, linker errors can happen. Fixed in already.

  • Standalone: Do not load site module early anymore. This might have caused issues in some configurations, but really only would be needed for loading inspect which doesn`t depend on it in standalone mode. Fixed in already.

  • Fix, could crash with generator expressions in finally blocks of tried blocks that return. Fixed in already.

       return 9
       "".join(x for x in b"some_iterable")
  • Python3.5+: Compatibility of comparisons with types.CoroutineType and types.AsyncGeneratorType types was not yet implemented. Fixed in already.

    # These already worked:
    assert isinstance(compiledCoroutine(), types.CoroutineType) is True
    assert isinstance(compiledAsyncgen(), types.AsyncGeneratorType) is True
    # These now work too:
    assert type(compiledCoroutine()) == types.CoroutineType
    assert type(compiledAsyncgen()) == types.AsyncGeneratorType
  • Standalone: Added support for ruamel.yaml. Fixed in already.

  • Distutils: Fix, when building more than one package, things could go wrong. Fixed in already.

  • Fix, for module mode filenames are used, and for packages, you can specify a directory, however, a trailing slash was not working. Fixed in already.

  • Compatibility: Fix, when locating modules, a package directory and an extension module of the same name were not used according to priority. Fixed in already.

  • Standalone: Added workaround importlib_resources insisting on Python source files to exist to be able to load datafiles. Fixed in already.

  • Standalone: Properly detect usage of hard imports from standard library in --follow-stdlib mode.

  • Standalone: Added data files for opensapi_spec_validator.

  • MSYS2: Fix, need to normalize compiler paths before comparing.

  • Anaconda: For accelerated binaries, the created .cmd file wasn’t containing all needed environment.

  • macOS: Set minimum OS version derived from the Python executable used, this should make it work on all supported platforms (of that Python).

  • Standalone: Added support for automatic inclusion of xmlschema package datafiles.

  • Standalone: Added support for automatic inclusion of eel package datafiles.

  • Standalone: Added support for h5py package.

  • Standalone: Added support for phonenumbers package.

  • Standalone: Added support for feedparser package, this currently depends on the anti-bloat plugin to be enabled, which will become enabled by default in the future.

  • Standalone: Added gi plugin for said package that copies typelib files and sets the search path for them in standalone mode.

  • Standalone: Added necessary datafiles for eel package.

  • Standalone: Added support for QtWebEngine to all Qt bindings and also make it work on Linux. Before only PySide2 on Windows was supported.

  • Python3: Fix, the all built-in was wrongly assuming that bytes values could not be false, but in fact they are if they contain \0 which is actually false. The same does not happen for string values, but that’s a difference to be considered.

  • Windows: The LTO was supposed to be used automatically on with MSVC 14.2 or higher, but that was regressed and has been repaired now.

  • Standalone: Extension modules contained in packages, depending on their mode of loading had the __package__ value set to a wrong value, which at least impacted new matplotlib detection of Qt backend.

  • Windows: The python install was installing binaries for no good reason.

New Features

  • Setuptools support. Documented bdist_nuitka and bdist_wheel integration and added support for Nuitka as a build package backend in pyproject.toml files. Using Nuitka to build your wheels is supposed to be easy now.

  • Added experimental support for Python 3.10, there are however still important issues with compatibility with the CPython 3.9 test suite with at least asyncgen and coroutines.

  • macOS: For app bundles, version information can be provided with the new option --macos-app-version.

  • Added Python vendor detection of Anaconda, pyenv, Apple Python, and pyenv and output the result in version output, this should make it easiert to analyse reported issues.

  • Plugins: Also handle the usage of __name__ for metadata version resolution of the pkg-resources standard plugin.

  • Plugins: The data-files standard plugin now reads configuration from a Yaml file that data-files.yml making it more accessible for contributions.

  • Windows: Allow enforcing usage of MSVC with --msvc=latest. This allows you to prevent accidental usage of MinGW64 on Windows, when MSVC is intended, but achieves that without fixing the version to use.

  • Windows: Added support for LTO with MinGW64 on Windows, this was previously limited to the MSVC compiler only.

  • Windows: Added support for using --debugger with the downloaded MinGW64 provided gdb.exe.


    It doesn`t work when executed from a Git bash prompt, but e.g. from a standard command prompt.

  • Added new experimental flag for compiled types to inherit from uncompiled types. This should allow easier and more complete compatibility, making even code in extension modules that uses PyObject_IsInstance work, providing support for packages like pydantic.

  • Plugins: The Qt binding plugins now resolve pyqtgraph selection of binding by hard coding QT_LIB. This will allow to resolve its own dynamic imports depending on that variable at compile time. At this time, the compile time analysis is not covering all cases yet, but we hope to get there.

  • macOS: Provide minOS for standalone builds, derived from the setting of the Python used to create it.

  • UI: Added new option --disable-ccache to prevent Nuitka from injecting ccache (Clang, gcc) and clcache (MSVC) for caching the C results of the compilation.

  • Plugins: Added experimental support for PyQt6. While using PySide2 or PySide6 is very much recommended with Nuitka, this allows its use.

  • UI: Added option --low-memory to allow the user to specify that the compilation should attempt to use less memory where possible, this increases compile times, but might enable compilation on some weaker machines.


  • Added dedicated attribute nodes for attribute values that match names of dictionary operations. These are optimized into dedicate nodes for methods of dictionaries should their expression have an exact dictionary shape. These in turn optimize calls on them statically into dictionary operations. This is done for all methods of dict for both Python2 and Python3, namely get, items, iteritems, itervalues, iterkeys, viewvalues, viewkeys, pop, setdefault, has_key, clear, copy, update.

    The new operation nodes also add compile time optimization for being used on constant values where possible.

  • Also added dedicated attribute nodes for string operations. For operations, currently only part of the methods are done. These are currently only join, strip, lstrip, rstrip, partition, rpartition. Besides performance, this subset was enough to cover compile time evaluation of module name computation for importlib.import_module as done by SWIG bindings, allowing these implicit dependencies to be discovered at compile time without any help, marking a significant improvement for standalone usage.

  • Annotate type shape for dictionary in/not in nodes, this was missing unlike in the generic in/not in nodes.

  • Faster processing of “expression only” statement nodes. These are nodes, where a value is computed, but then not used, it still needs to be accounted for though, representing the value release.

    something() # ignores return value, means statement only node
  • Windows: Enabled LTO by default with MinGW64, which makes it produce much faster results. It now yield faster binaries than MSVC 2019 with pystone.

  • Windows: Added support for C level PGO (Profile Guided Optimization) with MSVC and MinGW64, allowing extra speed boosts from the C compilation on Windows as well.

  • Standalone: Better handling of requests.packages and six.moves. The old handling could duplicate their code. Now uses a new mechanism to resolve metapath based importer effects at compile time.

  • Avoid useless exception checks in our dictionary helpers, as these could only occur when working with dictionary overloads, which we know to not be the case.

  • For nodes, have dedicated child mixin classes for nodes with a single child value and for nodes with a tuple of children, so that these common kind of nodes operate faster and don’t have to check at run time what type they are during access.

  • Actually make use of the egg cache. Nuitka was unpacking eggs in every compilation, but in wheel installs, these can be quite common and should be faster.

  • Star arguments annotated their type shape, but the methods to check for dictionary exactly were not affected by this preventing optimization in some cases.

  • Added anti-bloat configuration for main programs present in the modules of the standard library, these can be removed from the compilation and should lower dependencies detected.

  • Using static libpython with pyenv automatically. This should give both smaller (standalone mode) and faster results as is the case when using this feature..

  • Plugins: Added improvements to the anti-bloat plugin for gevent to avoid including its testing framework.

  • Python3.9+: Faster calls into uncompiled functions from compiled code using newly introduced API of that version.

  • Statically optimize importlib.import_module calls with constant args into fixed name imports.

  • Added support for sys.version_info to be used as a compile time constant. This should enable many checks to be done at compile time.

  • Added hard import and static optimization for typing.TYPE_CHECKING.

  • Also compute named import lookup through variables, expanding their use to more cases, e.g. like this:

    import sys
    if sys.version_info.major >= 3:
  • Also optimize compile time comparisons through variable names if possible, i.e. the value cannot have changed.

  • Faster calls of uncompiled code with Python3.9 or higher avoiding DLL call overhead.


  • Commercial: There are Buy Now buttons available now for the direct purchase of the Nuitka Commercial offering. Finally Credit Card, Google Pay, and Apple Pay are all possible. This is using Stripe. Get in touch with me if you want to use bank transfer, which is of course still best for me.

  • The main script runners for Python2 have been renamed to nuitka2 and nuitka2-run, which is consistent with what we do for Python3, and avoids issues where bin folder ends up in sys.path and prevents the loading of nuitka package.

  • Windows: Added support for Visual Studio 2022 by updating the inline copy of Scons used for Windows to version 4.3.0, on non Windows, the other ones will keep being used.

  • Windows: Requiring latest MinGW64 with version 11.2 as released by winlibs, because this is known to allow LTO, where previous releases were missing needed binaries.

  • Reject standalone mode usage with Apple Python, as it works only with the other supported Pythons, avoiding pitfalls in attempting to distribute it.

  • Move hosting of documentation to Sphinx, added Changelog and some early parts of API documentation there too. This gives much more readable results than what we have done so far with Nikola. More things will move there.

  • User Manual: Add description how to access code attributes in nuitka-project style options.

  • User Manual: Added commands used to generate performance numbers for Python.

  • User Manual: List other Python’s for which static linking is supposed to work.

  • Improved help for --include-package with a hint how to exclude some of the subpackages.

  • Started using Jinja2 in code templates with a few types, adding basic infrastructure to do that. This will be expanded in the future.

  • Updated plugin documentation with more recent information.

  • Added Python flavor as detected to the --version output for improved bug reports.

  • Linux: Added distribution name to --version output for improved bug reports.

  • Always enable the gevent plugin, we want to achieve this for all plugins, and this is only a step in that direction.

  • Added project URLs for PyPI, so people looking at it from there have some immediate places to checkout.

  • Debian: Use common code for included PDF files, which have page styles and automatic corrections for rst2pdf applied.

  • Updated to latest black, isort, pylint versions.

  • The binary names for Python2 changed from nuitka and nuitka-run to nuitka2 and nuitka2-run. This harmonizes it with Python2 and avoids issues, where the bin folder in sys.path can cause issues with re-execution of Nuitka finding those to import.


    You ought to be using python -m nuitka style of calling Nuitka anyway, as it gives you best control over what Python is used to run Nuitka, you can pick python2 there if you want it to run with that, even with full path. Check the relevant section in the User Manual too.

  • Added support for Fedora 34 and Fedora 35.


  • In a change of mind --enable-plugin has become the only form to enable a plugin used in documentation and tests.

  • Massive cleanup of numpy and Qt binding plugins, e.g. pyside2. Data files and DLLs are now provided through proper declarative objects rather than copied manually. The handling of PyQt5 from the plugin should have improved as a side effect.

  • Massive cleanups of all documentation in ReST format. Plenty of formatting errors were resolved. Many typos were identified and globally fixed. Spellings e.g. of “Developer Manual” are now enforced with automatic replacements. Also missing or wrong quotes were turned to proper methods. Also enforce code language for shell scripts to be the same everywhere.

  • Removed last usages of getPythonFlags() and made the function private, replacing their use with dedicated function to check for individual flags.

  • Avoid string comparison with nuitka.utils.getOS() and instead add accessors that are more readable, e.g. nuitka.utils.isMacOS() and put them to use where it makes sense.

  • Replaced usages of string tests in list of python flags specified, with functions that check for a specific name with a speaking function name.

  • Added mixin for expressions that have no side effect outside of their value, providing common method implementation more consistently.

  • Remove code geared to using old PyLint and on Python2, we no longer use that. Also removed annotations only used for overriding Python2 builtins from Nuitka code.

  • The PDF specific annotations were moved into being applied only in the PDF building step, avoiding errors for raw PDF directives.

  • Apply Visual Code auto-format to our Yaml files. This is unfortunately not and automatic formatting yet.

  • Introduce dedicated nuitka.utils.Json module, as we intend to expand its usage, e.g. for caching.

  • Replacing remaining usages of print functions with uses of nuitka.Tracing instead.

  • Massive cleanup of the gevent plugin, user proper method to execute code after module load, rather than source patching without need. The plugin no longer messes with inclusions that other code already provides for standalone.

  • Using own helper to update sys module attributes, to avoid errors from old C compilers, and also cleaning up using code to not have to cast on string constants.

  • More consistent naming of plugin classes, and enforce a relationship of detector class names to the names of detected plugins. The new naming consistency is now enforced.


  • Added CPython 3.10 test suite, it needs more work though.

  • Added generated test that exercises dictionary methods in multiple variations.

  • Test suite names were specified wrongly in a few of them.


This release is again a huge step forward. It refines on PGO and LTO for C level to work with all relevant compilers. Internally Python level PGO is prepared, but only a future release will feature it. With that, scalability improvements as well as even more performance improvements will be unlocked.

The amount of optimization added this time is even bigger, some of which unlocks static optimization of module imports, that previously would have to be considered implicit. This work will need one extra step, namely to also trace hard imports on the function level, then this will be an extremely powerful tool to solve these kinds of issues in the future. The next release will have this and go even further in this area.

With the dictionary methods, and some string methods, also a whole new kind of optimization has been started. These will make working with dict containers faster, but obviously a lot of ground is to cover there still, e.g. list values are a natural target not yet started. Future releases will progress here.

Type specialization for Python3 has not progressed though, and will have to be featured in a future releases though.

For scalability, the anti-bloat work has continued, and this should be the last release, where this is not on by default. Compiling without it is something that is immediately noticeable in exploding module amounts. It is very urgently recommended to enable it for your compilations.

The support for macOS has been refined, with version information being possible to add, and adding information to the binary about which OSes are supported, as well as rejecting Apple Python, which is only a trap if you want to deploy to other OS versions. More work will be needed to support pyenv or even Homebrew there too, for now CPython is still the recommended platform to use.

This release achieves major compatibility improvements. And of course, the experimental support for 3.10 is not the least. The next release will strive to complete the support for it fully, but this should be usable at least, for now please stay on 3.9 if you can.

Nuitka Release 0.6.17

This release has a focus on performance improvements, while also polishing plugins and adding many new features.

Bug Fixes

  • Fix, plugins were not catching being used on packages not installed. Fixed in already.

  • macOS: Fix weaknesses in the otool parsing to determine DLL dependency parsing. Fixed in already.

  • Linux: Allow onefile program args with spaces contained to be properly passed. Fixed in already.

  • Windows: Avoid using less portable C function for %PID% formatting, which restores compilation on Windows 7 with old toolchains. Fixed in already.

  • Standalone: Added support for fstrings package. Fixed in already.

  • Compatibility: Fix, need to import .pth files after site module, not before. This was causing crashes on CentOS7 with Python2. Fixed in already.

  • Compatibility: Fix, when extension modules failed to load, in some cases the ImportError was lost to a KeyError. Fixed in already.

  • Fix, linker resource modes code and linker were not working anymore, but are needed with LTO mode at least. Fixed in already.

  • Standalone: Bytecode modules with null bytes in standard library, typically from disk corruption, were not handled properly. Fixed in already.

  • Fix, failed .throw() into generators could cause corruption. Fixed in already.

  • Python2: Fix, the bytecode compilation didn’t respect the --python-flag=no_asserts mode. Fixed in already.

  • Fix, calls were not annotating their arguments as escaped, causing corruption of mutable in static optimization. Fixed in already.

  • Fix, some sequence objects, e.g. numpy.array actually implement in-place add operations that need to be called. Fixed in already.

  • Windows: Fix, onefile binaries were not working after being signed. This now works.

  • Standalone: Added missing implicit dependency for sklearn.

  • Compatibility: Modules giving SyntaxError from source were not properly handled, giving run time ImportError. Now they are giving SyntaxError.

  • Fix, the LTO mode has issues with incbin usage on older gcc, so use linker mode when it is enabled.

  • Python3: Fix, locals dict codes were not properly checking errors that the mapping might raise when setting values.

  • Fix, modules named entry were causing compile time errors in the C stage.

  • macOS: Never include files from OS private frameworks in standalone mode.

  • Fix, the python flag --python-flag=no_warning wasn’t working on all platforms.

  • Compatibility: Fix, the main code of the site module wasn’t executing, so that its added builtins were not there. Of course, you ought to use --python-flag=no_site to not have it in the normal case.

  • Python2: Added code path to handle edited standard library source code which then has no valid bytecode file.

  • Anaconda: In module mode, the CondaCC wasn’t recognized as form of gcc.

  • Fix, bytecode modules could shadow compiled modules of the same name.

  • Onefile: Fix, expansion of %PID% wasn’t working properly on non-Windows, making temp paths less unique. The time stamp is not necessarily enough.

  • Fix, multiprocessing error exits from slave processes were not reporting tracebacks.

  • Standalone: Added xcbglintegrations to the list of sensible Qt plugins to include by default, otherwise rendering will be inferior.

  • Standalone: Added platformthemes to the list of sensible Qt plugins to include by default, otherwise file dialogs on non-Windows would be inferior.

  • Fix, created .pyi files were not ordered deterministically.

  • Standalone: Added support for win32file.

  • Fix, namespace packages were not using run time values for their __path__ value.

  • Python3.7+: Fix, was leaking AttributeError exceptions during name imports.

  • Fix, standard library detection could fail for relative paths.

New Features

  • Added experimental support for C level PGO (Profile Guided Optimization), which runs your program and then uses feedback from the execution. At this time only gcc is supported, and only C compiler is collecting feedback. Check the User Manual for a table with current results.

  • macOS: Added experimental support for creating application bundles. For these, icons can be specified and console can be disabled. But at this time, onefile and accelerated mode are not yet usable with it, only standalone mode works.

  • Plugins: Add support for pkg_resources.require calls to be resolved at compile time. These are not working at run time, but this avoids the issue very nicely.

  • Plugins: Massive improvements to the anti-bloat plugin, it can now make numpy, scipy, skimage, pywt, and matplotlib use much less packages and has better error handling.

  • Plugins: Added anti-bloat ability ability to append code to a module, which might get used in the future by other plugins that need some sort of post load changes to be applied.

  • Plugins: Added ability to replace code of functions at parse time, and use this in anti-bloat plugin to replace functions that do unnecessary stuff with variants that often just do nothing. This is illustrated here.

    description: "remove gevent release framework"
       "prereleaser_middle": "'(lambda data: None)'"
       "postreleaser_before": "'(lambda data: None)'"

    This example is removing gevent code that loads dependencies used for their CI release process, that need not be part of normal programs.

  • Added ability to persist source code changes done by plugins in the Python installation. This is considered experimental and needs write access to the Python installation, so this is best done in a virtualenv and it may confuse plugins.

  • Added support for multiprocessing.tracker and spawn mode for all platforms. For non-default modes outside of Windows, you need to --enable-plugin=multiprocessing to use these.

  • Plugins: Allow multiple entry points to be provided by one or several plugins for the same modules. These are now merged into one automatically.

  • Standalone: Fix for numpy not working when compiling with --python-flag=no_docstrings.

  • Fix, method calls were not respecting descriptors provided by types with non-generic attribute lookups.

  • Windows: Add support for using self-compiled Python3 from the build folder too.

  • Added support for Nuitka-Python 2.7, which will be our faster Python fork.

  • Colorized output for error outputs encountered in Scons, these are now yellow for better recognition.


  • Faster threading code was used for Python3.8 or higher, and this has been extended to 3.7 on Windows, but we won’t be able to have it other platforms and not on earlier Python3 versions.

  • Faster calls esp. with keyword arguments. Call with keywords no longer create dictionaries if the call target supports that, and with 3.8 or higher, non-compiled code that allows vectorcall is taken advantage of.

  • Faster class creation that avoids creation of argument tuples and dictionaries.

  • Faster attribute check code in case of non-present attributes.

  • Faster unbound method calls, unlike bound methods calls these were not optimized as well yet.

  • Type shapes for star arguments are now known and used in optimization.

    def f(*args, **kwargs):
       type(args) # Statically known to be tuple
       type(kwargs) # Statically known to be dict
  • Python2: Faster old-style class creation. These are classes that do not explicitly inherit from object.

  • Python2: Faster string comparisons for Python by specializing for the str type as well.

  • Python3: Added specialization for bytes comparisons too. These are naturally very much the same as str comparisons in Python2.

  • Added specialization for list comparisons too. We had them for tuples only so far.

  • Faster method calls when called from Python core, our tp_call slot wasn’t as good as it can be.

  • Optimization: Faster deep copies of constants. This can speed up constant calls with mutable types. Before it was checking the type too often to be fast.

  • Allow using static linking with Debian Python giving much better performance with the system Python. This is actually a huge improvement as it makes things much faster. So far it’s only automatically enabled for Python2, but it seems to work for Python3 on Debian too. Needs more tweaking in the future.

  • Optimization: Added functools module to the list of hard imports in preparation of optimizing functools.partial to work better with compiled functions.

  • Python2: Demote to xrange when iterating over range calls, even for small ranges, they are always faster. Previously this was only done for values with at least 256 values.

  • Enable LTO automatically for Debian Python, this also allows more optimization.

  • Enable LTO automatically for Anaconda with CondaCC on non-Windows, also allowing more optimization.


  • Added section in the User Manual on how to deal with memory issues and C compiler bugs. This is a frequent topic and should serve as a pointer for this kind of issue.

  • The --lto option was changed to require an argument, so that it can also be disabled. The default is auto which is the old behaviour where it’s enabled if possible.

  • Changed --no-progress to --no-progressbar in order to make it more clear what it’s about. Previously it was possible to relate it to --show-progress.

  • No longer require specific versions of dependencies in our requirements.txt and relegate those to only being in requirements-devel.txt such that by default Nuitka doesn’t collide with user requirements on those same packages which absolutely all the time don’t really make a difference.

  • Added ability to check all unpushed changes with pylint with a new ./bin/check-nuitka-with-pylint --unpushed option. Before it was only possible to make the check (quickly) with --diff, but that stopped working after commits are made.

  • Revived support for vmprof based analysis of compiled programs, but it requires a fork of it now.

  • Make Windows specific compiler options visible on all platforms. There is no point in them being errors, instead warnings are given when they are specified on non-Windows.

  • Added project variable Commercial for use in Nuitka project syntax.

  • Consistent use of metavars for nicer help output should make it more readable.

  • Avoid ast tree dumps in case of KeyboardInterrupt exceptions, they are just very noisy. Also not annotate where Nuitka was in optimization when a plugin is asking to sysexit.


  • Encoding names for UTF-8 in calls to .encode() were used inconsistent with and without dashes in the source code, added cleanup to auto-format that picks the one blessed.

  • Cleanup taking of run time traces of DLLs used in preparation for using it in main code eventually, moving it to a dedicated module.

  • Avoid special names for Nuitka options in test runner, this only adds a level of confusion. Needs more work in future release.

  • Unify implementation to create modules into single function. We had 3 forms, one in recursion, one for main module, and one for plugin generated code. This makes it much easier to understand and use in plugins.

  • Further reduced code duplication between the two Scons files, but more work will be needed there.

  • Escaped variables are still known to be assigned/unassigned rather than unknown, allowing for many optimizations to still work on them., esp. for immutable value

  • Enhanced auto-format for rest documents, bullet list spacing is now consistent and spelling of organisational is unified automatically.

  • Moved icon conversion functionality to separate module, so it can be reused for other platforms more easily.


  • Removed reflected test, because of Nuitka special needs to restart with variable Python flags. This could be reverted though, since Nuitka no longer needs anything outside inline copies, and therefore no longer loads from site packages.

  • Use anti-bloat plugin in standalone tests of Numpy, Pandas and tests to reduce their compile times, these have become much more manageable now.

  • Enhanced checks for used files to use proper below path checks for their ignoring.

  • Remove reflected test, compiling Nuitka with Nuitka has gotten too difficult.

  • Verify constants integrity at program end in debug mode again, so we catch corruption of them in tests.


This release is one of the most important ones in a long time. The PGO and LTO, and static libpython work make a big different for performance of created binaries.

The amount of optimization added is also huge, calls are much faster now, and object creations too. These avoiding to go through actual dictionaries and tuples in most cases when compiled code interacts gives very significant gains. This can be seen in the increase of pystone performance.

The new type specializations allow many operations to be much faster. More work will follow in this area and important types, str and int do not have specialized comparisons for Python3, holding it back somewhat to where our Python2 performance is for these things.

For scalability, the anti-bloat work is extremely valuable, and this plugin should become active by default in the future, for now it must be strongly recommended. It needs more control over what parts you want to deactivate from it, in case of it causing problems, then we can and should do it.

The support for macOS has been enhanced a lot, and will become perfect in the next release (currently develop). The bundle mode is needed for all kinds of GUI programs to not need a console. This platform is becoming as well supported as the others now.

Generally this release marks a huge step forward. We hope to add Python level PGO in the coming releases, for type knowledge retrofitted without any annotations used. Benchmarks will become more fun clearly.

Nuitka Release 0.6.16

This release is mostly polishing and new features. Optimization looked only at threading performance, and LTO improvements on Windows.

Bug Fixes

  • Fix, the pkg-resources failed to resolve versions for importlib.metadata from its standard library at compile time. Fixed in already.

  • Standalone: Fix, --include-module was not including the module if it was an extension modules, but only for Python modules. Fixed in already.

  • Standalone: Added missing implicit dependencies for gi.overrides. Fixed in already.

  • Python3.9: Fix, could crash when using generic aliases in certain configurations. Fixed in already.

  • Fix, the tensorflow plugin needed an update due to changed API. Fixed in already.

  • When error exiting Nuitka, it now closes any open progress bar for cleaner display.

  • Standalone: Added missing dependency for skimage.

  • Standalone: The numpy plugin now automatically includes Qt backend if any of the Qt binding plugins is active.

New Features

  • Python3.5+: Added support for onefile compression. This is using zstd which is known to give very good compression with very high decompression, much better than e.g. zlib.

  • macOS: Added onefile support.

  • FreeBSD: Added onefile support.

  • Linux: Added method to use tempdir onefile support as used on other platforms as an alternative to AppImage based.

  • Added support for recursive addition of files from directories with patterns.

  • Attaching the payload to onefile now has a progress bar too.

  • Windows: Prelimary support for the yet unfinished Nuitka-Python that allows static linking and higher performance on Windows, esp. with Nuitka.

  • Windows: In acceleration mode, for uninstalled Python, now a CMD file is created rather than copying the DLL to the binary directory. That avoids conflicts with architectures and of course useless file copies.

  • New abilities for plugin anti-bloat allow to make it an error when certain modules are imported. Added more specific options for usual trouble makes, esp. setuptools, pytest are causing an explosion for some programs, while being unused code. This makes it now easier to oversee this.

  • It’s now possible to override appdirs decision for where cache files live with an environment variable NUITKA_CACHE_DIR.

  • The -o option now also works with onefile mode, it previously rejected anything but acceleration mode. Fixed in already.

  • Plugins: It’s now possible for multiple plugins to provide pre or post load code for the same module.

  • Added indications for compilation modes standalone and onefile to the __compiled__ attribute.

  • Plugins: Give nicer error message in case of colliding command line options.


  • Faster threading code is now using for Python3.8 or higher and not only 3.9, giving a performance boost, esp. on Windows.

  • Using --lto is now the default with MSVC 2019 or higher. This will given smaller and faster binaries. It has been available for some time, but not been the default yet.


  • Using different progress bar titles for C compilation of Python code and C compilation of onefile bootstrap.

  • Moved platform specific detections, for FreeBSD/OpenBSD/macOS out of the Scons file and to common Nuitka code, sometimes eliminating duplications with one version being more correct than the other.

  • Massive cleanup of datafile plugin, using pattern descriptions, so more code duplication can be removed.

  • More cleanup of the scons files, sharing more common code.


  • Under the name Nuitka-Python we are now also developing a fork of CPython with enhancements, you can follow and joint it at but at this time it is not yet ready for prime time.

  • Onefile under Windows now only is temporary file mode. Until we figure out how to solve the problems with locking and caching, the mode where it installs to the AppData of the user is no longer available.

  • Renamed the plugin responsible for PyQt5 support to match the names of others. Note however, that at this time, PySide2 or PySide6 are to be recommended.

  • Make it clear that PySide 6.1.2 is actually going to be the supported version of PySide6.

  • Use MSVC in GitHub actions.


This release had a massive focus on expanding existing features, esp. for onefile, and plugins API, such that we can now configure anti-bloat with yaml, have really nice datafile handling options, and have onefile on all OSes practically.

Nuitka Release 0.6.15

This release polished previous work with bug fixes, but there are also important new things that help make Nuitka more usable, with one important performance improvement.

Bug Fixes

  • Fix, hard imports were not automatically used in code generation leading to errors when used. Fixed in already.

  • Windows: Fix, clcache was disabled by mistake. Fixed in already.

  • Standalone: Added data files for jsonschema to be copied automatically.

  • Standalone: Support for pendulum wasn’t working anymore with the last release due to plugin interface issues.

  • Retry downloads without SSL if that fails, as some Python do not have working SSL. Fixed in already.

  • Fix, the ccache path wasn’t working if it contained spaces. Fixed in already.

  • Onefile: For Linux and ARM using proper download off appimage. Fixed in already.

  • Standalone: Added support for pyreadstat. Fixed in already.

  • Standalone: Added missing dependencies for pandas. Fixed in already.

  • Standalone: Some preloaded packages from .pth do not have a __path__, these can and must be ignored.

  • Onefile: On Linux, the sys.argv[0] was not the original file as advertised.

  • Standalone: Do not consider .mesh and .frag files as DLls in the Qt bindings when including the qml support. This was causing errors on Linux, but was generally wasteful.

  • Fix, project options could be injected twice, which could lead to errors with options that were only allowed once, e.g. --linux-onefile-icon.

  • Windows: When updating the resources in created binaries, treat all kinds of OSError with information output.

  • Onefile: Remove onefile target binary path at startup as well, so it cannot cause confusion after error exit.

  • Onefile: In case of error exit from AppImage, preserve its outputs and attempt to detect if there was a locking issue.

  • Standalone: Scan package folders on Linux for DLLs too. This is necessary to properly handle PyQt5 in case of Qt installed in the system as well.

  • Standalone: On Linux, standard QML files were not found.

  • Standalone: Enforce C locale when detecting DLLs on Linux, otherwise whitelisting messages didn’t work properly on newer Linux.

  • Standalone: Added support for tzdata package data files.

  • Standalone: Added support for exchangelib.

  • Python3.9: Fix, type subscripts could cause optimization errors.

  • UI: Project options didn’t properly handle quoting of arguments, these are normally removed by the shell.

  • Linux: The default icon for Python in the system is now found with more version specific names and should work on more systems.

  • Standalone: Do not include libstdc++ as it should come from the system rather.

New Features

  • Added plugin anti-bloat plugin, intended to fight bloat. For now it can make including certain modules an error, a warning, or force ImportError, e.g. --noinclude-setuptools-mode=nofollow is very much recommended to limit compilation size.

  • The pkg-resources builtin now covers metadata and importlib_metadata packages for compile time version resolution as well.

  • Added support for PySide2 on Python version before 3.6, because the patched code needs no workarounds. Fixed in already.

  • Windows: Convert images to icon files on the fly. So now you can specify multiple PNG files, and Nuitka will create an icon out of that automatically.

  • macOS: Automatically download ccache binary if not present.

  • Plugins: New interface to query the main script path. This allows plugins to look at its directory.

  • UI: Output the versions of Nuitka and Python during compilation.

  • UI: Added option to control static linking. So far this had been enabled only automatically for cases where we are certain, but this allows to force enable or disable it. Now an info is given, if Nuitka thinks it might be possible to enable it, but doesn’t do it automatically.

  • UI: Added --no-onefile to disable --onefile from project options.


  • Much enhanced GIL interaction with Python3.9 giving a big speed boost and better threading behaviour.

  • Faster conversion of iterables to list, if size can be know, allocation ahead saves a lot of effort.

  • Added support for GenericAlias objects as compile time constants.


  • Enhanced GitHub issue raising instructions.

  • Apply rstfmt to all documentation and make it part of the commit hook.

  • Make sure to check Scons files as well. This would have caught the code used to disable clcache temporarily.

  • Do not mention Travis in PR template anymore, we have stopped using it.

  • Updated requirements to latest versions.

  • Bump requirements for development to 3.7 at least, toosl like black do not work with 3.6 anymore.

  • Started work on Nuitka Python, a CPython fork intended for enhanced performance and standalone support with Nuitka.


  • Determine system prefix without virtualenv outside of Scons, such that plugins can share the code. There was duplication with the numpy plugin, and this will only be more complete using all approaches. This also removes a lot of noise from the scons file moving it to shared code.

  • The Qt plugins now collect QML files with cleaner code.


  • Nicer error message if a wrong search mode is given.

  • Windows: Added timeout for determining run time traces with dependency walker, sometimes this hangs.

  • Added test to cover the zip importer.

  • Making use of project options in onefile tests, making it easier to execute them manually.


For Windows, it’s now easier than ever to create an icon for your deployment, because you can use PNG files, and need not produce ICO files anymore, with Nuitka doing that for you.

The onefile for Linux had some more or less severe problems that got addressed, esp. also when it came to QML applications with PySide.

On the side, we are preparing to greatly improve the caching of Nuitka, starting with retaining modules that were demoted to bytecode. There are changes in this release, to support that, but it’s not yet complete. We expect that scalability will then be possible to improve even further.

Generally this is mostly a maintenance release, which outside of the threading performance improvement has very little to offer for faster execution, but that actually does a lot. Unfortunately right now it’s limited to 3.9, but some of the newer Python’s will also be supported in later releases.

Nuitka Release 0.6.14

This release has few, but important bug fixes. The main focus was on expanding standalone support, esp. for PySide2, but also and in general with plugins added that workaround pkg_resources usage for version information.

Also an important new features was added, e.g. the project configuration in the main file should prove to be very useful.

Bug Fixes

  • Compatibility: Fix, modules that failed to import, should be retried on next import.

    So far we only ever executed the module body once, but that is not how it’s supposed to be. Instead, only if it’s in sys.modules that should happen, which is the case after successful import.

  • Compatibility: Fix, constant False values in right hand side of and/or conditions were generating wrong code if the left side was of known bool shape too.

  • Standalone: Fix, add styles Qt plugins to list of sensible plugins.

    Otherwise no mouse hover events are generated on some platforms.

  • Compatibility: Fix, relative from imports beyond level 1 were not loadingg modules from packages if necessary. Fixed in already.

  • Standalone: The crypto DLL check for Qt bindings was wrong. Fixed in already.

  • Standalone: Added experimental support for PySide6, but for good results, 6.1 will be needed.

  • Standalone: Added support for newer matplotlib. Fixed in already.

  • Standalone: Reverted changes related to pkg_resources that were causing regressions. Fixed in already.

  • Standalone: Adding missing implicit dependency for cytoolz package. Fixed in already.

  • Standalone: Matching for package names to not suggest recompile for was broken and didn’t match. Fixed in already.

New Features

  • Added support for project options.

    When found in the filename provided, Nuitka will inject options to the commandline, such that it becomes possible to do a complex project with only using

    python -m nuitka
    # Compilation mode, support OS specific.
    # nuitka-project-if: {OS} in ("Windows", "Linux"):
    #    nuitka-project: --onefile
    # nuitka-project-if: {OS} not in ("Windows", "Linux"):
    #    nuitka-project: --standalone
    # The PySide2 plugin covers qt-plugins
    # nuitka-project: --enable-plugin=pyside2
    # nuitka-project: --include-qt-plugins=sensible,qml
    # The pkg-resources plugin is not yet automatic
    # nuitka-project: --enable-plugin=pkg-resources
    # Nuitka Commercial only features follow:
    # Protect the constants from being readable.
    # nuitka-project: --enable-plugin=data-hiding
    # Include datafiles for Qt into the binary directory.
    # nuitka-project: --enable-plugin=datafile-inclusion
    # nuitka-project: --qt-datadir={MAIN_DIRECTORY}
    # nuitka-project: --qt-datafile-pattern=*.js
    # nuitka-project: --qt-datafile-pattern=*.qml
    # nuitka-project: --qt-datafile-pattern=*.svg
    # nuitka-project: --qt-datafile-pattern=*.png

    Refer to the User Manual for a table of directives and the variables allowed to be used.

  • Added option to include whole data directory structures in standalone.

    The new option --include-data-dir was added and is mostly required for onefile mode, but recommended for standalone too.

  • Added pkg-resources plugin.

    This one can resolve code like this at compile time without any need for pip metadata to be present or used.

  • Standalone: Also process early imports in optimization.

    Otherwise plugins cannot work on standard library modules. This makes it possible to handle them as well.


  • Faster binary operations.

    Applying lessons learnt during the enhancements for in-place operations that initially gave worse results than some manual code, we apply the same tricks for all binary operations, which speeds them up by significant margins, e.g. 30% for float addition, 25% for Python int addition, and still 6% for Python int addition.

  • More direct optimization of unary operations on constant value.

    Without this, -1 was not directly a constant value, but had to go through the unary - operation, which it still does, but now it’s done at tree building time.

  • More direct optimization for not in branches.

    Invertible comparisons, i.e. is/is not and in/not in do not have do be done during optimization. This mainly avoids noise during optimization from such unimportant steps.

  • More direct optimization for constant slices.

    These are used in Python3 for all subscripts, e.g. a[1:2] will use slice(1,2) effectively. For Python2 they are used less often, but still. This also avoids a lot of noise during optimization, mostly on Python3

  • Scons: Avoid writing database to disk entirely.

    This saves a bit of disk churn and makes it unnecessary to specify the location such that it doesn’t collide between Python versions.

  • For optimization passes, use previous max total as minimum for next pass. That will usually be a more accurate result, rather than starting from 1 again. Part of already.

  • Enhancements to the branch merging improve the scalability of Nuitka somewhat, although the merging itself is still not very scalable, there are some modules that are very slow to optimize still.

  • Use orderset if available over the inline copy for OrderedSet which is much faster and improves Nuitka compile times.

  • Make pkgutil a hard import too, this is in preparation of more optimization for its functions.


  • Upstream patches for PySide6 have been contributed and merged into the development branch dev. Full support should be available once this is released as part of 6.1 which is waiting for Qt 6.1 naturally.

  • Patches for PySide2 are available to commercial customers, see PySide2 support page.

  • Formatted all documents with rstfmt and made that part of the commit hook for Nuitka. It now works for all documents we have.

  • Updated inline copy of tqdm to 4.59.0 which ought to address spurious errors given.

  • User Manual: Remove --show-progress from the tutoral. The default progress bar is then disabled, and is actually much nicer to use.

  • Developer Manual: Added description of how context managers should be named.

  • Cleanup language for some warnings and outputs.

    It was still using obsolete “recursion” language rather than talking about “following imports”, which is the new one.


  • Remove dead code related to constants marshal, the data composer has replaced this.

  • Avoid internal API usage for loading extension modules on Linux, there is a function in sys module to get the ld flags.


  • Fix, the only mode wasn’t working properly.

  • Use new project options feature for specific options in basic tests allowing to remove them from the test runner.


For PySide2 things became more perfect, but it takes upstream patches unfortunately such that only PySide6.1 will be working out of the box outside of the commercial offering. We will also attempt to provide workarounds, but there are some things that cannot be done that way.

This release added some more scalability to the optimization process, however there will be more work needed to make efficient branch merges.

For onefile, a feature to include whole directories had been missing, and could not easily be achieved with the existing options. This further rounds this up, now what’s considered missing is compression and macOS support, both of which should be coming in a future release.

For the performance side of things, the binary operator work can actually yield pretty good gains, with double digit improvements, but this covers only so much. Much more C types and better type tracing would be needed, but there was no progress on this front. Future releases will have to revisit the type tracing to make sure, we know more about loop variables, etc. so we can achieve the near C speed we are looking for, at least in the field of int performance.

This release has largely been driven by the Nuitka Commercial offering and needs for compatibility with more code, which is of course always a good thing.

Nuitka Release 0.6.13

This release follows up with yet again massive improvement in many ways with lots of bug fixes and new features.

Bug Fixes

  • Windows: Icon group entries were not still not working properly in some cases, leading to no icon or too small icons being displayed. Fixed in already.

  • Windows: Icons and version information were copied from the standalone executable to the onefile executable, but that failed due to race situations, sometimes reproducible. Instead we now apply things to both independently. Fixed in already.

  • Standalone: Fixup scanning for DLLs with ldconfig on Linux and newer versions making unexpected outputs. Fixed in already.

  • UI: When there is no standard input provided, prompts were crashing with EOFError when --assume-yes-for-downloads is not given, change that to defaulting to "no" instead. Fixed in already.

  • Windows: Detect empty strings for company name, product name, product and file versions rather than crashing on them later. Them being empty rather than not there can cause a lot of issues in other places. Fixed in already.

  • Scons: Pass on exceptions during execution in worker threads and abort compilation immediately. Fixed in already.

  • Python3.9: Still not fully compatible with typing subclasses, the enhanced check is now closely matching the CPython code. Fixed in already.

  • Linux: Nicer error message for missing libfuse requirement.

  • Compatibility: Lookups on dictionaries with None value giving a KeyError exception, but with no value, which is not what CPython does.

  • Python3.9: Fix, future annotations were crashing in debug mode. Fixed in already.

  • Standalone: Corrections to the glfw were made. Fixed in already.

  • Standalone: Added missing ìmplicit dependency for py.test. Fixed in already.

  • Standalone: Adding missing implicit dependency for pyreadstat.

  • Windows: Added workaround for common clcache locking problems. Since we use it only inside a single Scons process, we can avoiding using Windows mutexes, and use a process level lock instead.

  • Plugins: Fix plugin for support for eventlet. Fixed in already.

  • Standalone: Added support for latest zmq on Windows.

  • Scons: the --quiet flag was not fully honored yet, with Scons still making a few outputs.

  • Standalone: Added support for alternative DLL name for newer PyGTK3 on Windows. Fixed in already.

  • Plugins: Fix plugin for support for gevent. Fixed in already.

  • Standalone: Added yet another missing implicit dependency for pandas.

  • Plugins: Fix, the qt-plugins plugin could stumble over .mesh files.

  • Windows: Fix, dependency walker wasn’t properly working with unicode %PATH% which could e.g. happen with a virtualenv in a home directory that requires them.

  • Python3: Fixed a few Python debug mode warnings about unclosed files that have sneaked into the codebase.

New Features

  • Added new options --windows-force-stdout-spec and --windows-force-stderr-spec to force output to files. The paths provided at compile time can resolve symbolic paths, and are intended to e.g. place these files near the executable. Check the User Manual for a table of the currently supported values. At this time, the feature is limited to Windows, where the need arose first, but it will be ported to other supported OSes eventually. These are most useful for programs run as --windows-disable-console or with --enable-plugin=windows-service.


    These options have since been renamed to --force-stdout and --force-stderr and have been made to work on all OSes.

  • Windows: Added option --windows-onefile-tempdir-spec (since renamed to --onefile-tempdir-spec) to provide the temporary directory used with --windows-onefile-tempdir in onefile mode, you can now select your own pattern, and e.g. hardcode a base directory of your choice rather than %TEMP.

  • Added experimental support for PySide2 with workarounds for compiled methods not being accepted by its core. There are known issues with PySide2 still, but it’s working fine for some people now. Upstream patches will have to be created to remove the need for workarounds and full support.


  • Use binary operation code for their in-place variants too, giving substantial performance improvements in all cases that were not dealt with manually already, but were covered in standard binary operations. Until now only some string, some float operations were caught sped up, most often due to findings of Nuitka being terribly slower, e.g. not reusing string memory for inplace concatenation, but now all operations have code that avoids a generic code path, that is also very slow on Windows due calling to using the embedded Python via API being slow.

  • For mixed type operations, there was only one direction provided, which caused fallbacks to slower forms, e.g. with long and float values leading to inconsistent results, such that a - 1 and 1 - a being accelerated or not.

  • Added C boolean optimization for a few operations that didn’t have it, as these allow to avoid doing full computation of what the object result would have to do. This is not exhausted fully yet.

  • Python3: Faster +/-/+=/-= binary and in-place operations with int values providing specialized code helpers that are much faster, esp. in cases where no new storage is allocated for in-place results and where not a lot of digits are involved.

  • Python2: The Python3 int code is the Python2 long type and benefits from the optimization of +/-/+=/-= code as well, but of course its use is relatively rare.

  • Improved __future__ imports to become hard imports, so more efficient code is generated for them.

  • Counting of instances had a run time impact by providing a __del__ that was still needed to be executed and limits garbage collection on types with older Python versions.

  • UI: Avoid loading tqdm module before it’s actually used if at all (it may get disabled by the user), speeding up the start of Nuitka.

  • Make sure to optimize internal helpers only once and immediately, avoiding extra global passes that were slowing down Python level compilation by of large programs by a lot.

  • Make sure to recognize the case where a module optimization can provide no immediate change, but only after a next run, avoiding extra global passes originating from these, that were slowing down compilation of large programs by a lot. Together with the other change, this can improve scalability by a lot.

  • Plugins: Remove implicit dependencies for pkg_resources.extern and use aliases instead. Using one of the packages, was causing all that might be used, to be considered as used, with some being relatively large. This was kind of a mistake in how we supported this so far.

  • Plugins: Revamped the eventlet plugin, include needed DNS modules as bytecode rather than as source code, scanning them with pkgutil rather than filesystem, with much cleaner code in the plugin. The plugin is also now enabled by default.


  • Removed support for pefile dependency walker choice and inline copy of the code. It was never as good giving incomplete results, and after later improvements, slower, and therefore has lost the original benefit over using Dependency Walker that is faster and more correct.

  • Added example for onefile on Windows with the version information and with the temporary directory mode.

  • Describe difference in file access with onefile on Windows, where sys.argv[0] and os.path.dirname(__file__) will be different things.

  • Added inline copy of tqdm to make sure it’s available for progress bar output for 2.7 or higher. Recommend having it in the Debian package.

  • Added inline copy of colorama for use on Windows, where on some terminals it will give better results with the progress bar.

  • Stop using old PyLint for Python2, while it would be nice to catch errors, the burden of false alarms seems to high now.

  • UI: Added even more checks on options that make no sense, made sure to do this only after a possible restart in proper environment, so warnings are not duplicated.

  • For Linux onefile, keep appimage outputs in case of an error, that should help debugging it in case of issues.

  • UI: Added traces for plugin provided implicit dependencies leading to inclusions.

  • Added inline copy of zstd C code for use in decompression for the Windows onefile bootstrap, not yet used though.

  • Added checks to options that accept package names for obvious mistakes, such that --include-package-data --mingw64 will not swallow an option, as that is clearly not a package name, that would hide that option, while also not having any intended effect.

  • Added ignore list for decision to recompile extension modules with available source too. For now, Nuitka will not propose to recompile Cython modules that are very likely not used by the program anyway, and also not for lxml until it’s clear if there’s any benefit in that. More will be added in the future, this is mostly for cases, where Cython causes incompatibilities.

  • Added support for using abstract base classes in plugins. These are not considered for loading, and allow nicer implementation of shared code, e.g. between PyQt5 and PySide2 plugins, but allow e.g. to enforce the provision of certain overloads.

  • User Manual: Remove the instruction to install clcache, since it’s an inline copy, this makes no sense anymore and that was obsolete.

  • Updated PyLint to latest versions, and our requirements in general.


  • Started removal of PyLint annotations used for old Python2 only. This will be a continuous action to remove these.

  • Jinja2 based static code generation for operations was cleaned up, to avoid code for static mismatches in the result C, avoiding language constructs like if (1 && 0) with sometimes larger branches, replacing it with Jinja2 branches of the {% if ... %} form.

  • Jinja2 based Python2 int code was pioniering the use of macros, but this was expanded to allow kinds of types for binary operations, allow their reuse for in-place operation, with these macros making returns via goto exits rather than return statements in a function. Landing pads for these exits can then assign target values for in-place different from what those for binary operation result return do.

  • Changed the interfacing of plugins with DLL dependency detection, cleaning up the interactions considerably with more unified code, and faster executing due to cached plugin decisions.

  • Integrate manually provided slot function for unicode and str into the standard static code generation. Previously parts were generated and parts could be generated, but also provided with manual code. The later is now all gone.

  • Use a less verbose progress bar format with less useless infos, making it less likely to overflow.

  • Cleanup how payload data is accessed in Windows onefile bootstrap, preparing the addition of decompression, doing the reading from the file in only one dedicated function.

  • When Jinja2 generated exceptions in the static code, it is now done via proper Jinja2 macros rather than Python code, and these now avoid useless Python version branches where possible, e.g. because a type like bytes is already Python version specific, with the goal to get rid of PyErr_Format usage in our generated static code. That goal is future work though.

  • Move safe strings helpers (cannot overflow) to a dedicated file, and remove the partial duplication on the Windows onefile bootstrap code.

  • The Jinja2 static code generation was enhanced to track the usage of labels used as goto targets, so that error exits, and value typed exits from operations code no longer emitted when not used, and therefore labels that are not used are not present.

  • For implicit dependencies, the parsing of the .pyi file of a module no longer emits a dependency on the module itself. Also from plugins, these are now filtered away.


  • Detect if onefile mode has required downloads and if there is user consent, otherwise skip onefile tests in the test runner.

  • Need to also allow accesses to files via short paths on Windows if these are allowed long paths.

  • The standalone tests on Windows didn’t actually take run time traces and therefore were ineffective.

  • Added standalone test for glfw coverage.

  • Construct based tests for in-place operations are now using a value for the first time, and then a couple more times, allowing for real in-place usage, so we are sure we measure correctly if that’s happening.


Where the big change of the last release were optimization changes to reduce the global passes, this release addresses remaining causes for extra passes, that could cause these to still happen. That makes sure, Nuitka scalability is very much enhanced in this field again.

The new features for forced outputs are at this time Windows only and make a huge difference when it comes to providing a way to debug Windows Services or programs in general without a console, i.e. a GUI program. These will need even more specifiers, e.g. to cover program directory, rather than exe filename only, but it’s a very good start.

On the tooling side, not a lot has happened, with the clcache fix, it seems that locking issues on Windows are gone.

The plugin changes from previous releases had left a few of them in a state where they were not working, but this should be restored. Interaction with the plugins is being refined constantly, and this releases improved again on their interfaces. It will be a while until this becomes stable.

Adding support for PySide2 is a headline feature actually, but not as perfect as we are used to in other fields. More work will be needed, also in part with upstream changes, to get this to be fully supported.

For the performance side of things, the in-place work and the binary operations work has taken proof of concept stuff done for Python2 and applied it more universally to Python3. Until we cover all long operations, esp. * seems extremely important and is lacking, this cannot be considered complete, but it gives amazing speedups in some cases now.

Future releases will revisit the type tracing to make sure, we know more about loop variables, to apply specific code helpers more often, so we can achieve the near C speed we are looking for in the field of int performance.

Nuitka Release 0.6.12

This release is yet again a massive improvement in many ways with lots of bug fixes and new features.

Bug Fixes

  • Windows: Icon group entries were not working properly in some cases, leading to no icon or too small icons being displayed.

  • Standalone: The PyQt implicit dependencies were broken. Fixed in already.

  • Standalone: The datafile collector plugin was broken. Fixed in already.

  • Standalone: Added support for newer forms of matplotlib which need a different file layout and config file format. Fixed in already.

  • Plugins: If there was an error during loading of the module or plugin, it could still be attempted for use. Fixed in already.

  • Disable notes given by gcc, these were treated as errors. Fixed in already.

  • Windows: Fix, spaces in gcc installation paths were not working. Partially fixed in already.

  • Linux: Fix, missing onefile icon error message was not complete. Fixed in already.

  • Standalone: Workaround zmq problem on Windows by duplicating a DLL in both expected places. Fixed in already.

  • Standalone: The dill-compat plugin wasn’t working anymore. Fixed in already.

  • Windows: Fix mistaken usage of sizeof for wide character buffers. This caused Windows onefile mode in temporary directory. Fixed in already.

  • Windows: Fix, checking subfolder natured crashed with different drives on Windows. Fixed in already.

  • Windows: Fix, usage from MSVC prompt was no longer working, detect used SDK properly. Fixed in already.

  • Windows: Fix, old clcache installation uses pth files that prevented our inline copy from working, workaround was added.

  • Windows: Also specify stack size to be used when compiling with gcc or clang.

  • Fix, claim of Python 3.9 support also in PyPI metadata was missing. Fixed in already.

  • Python3.9: Subscripting type for annotations wasn’t yet implemented.

  • Python3.9: Better matching of types for metaclass selection, generic aliases were not yet working, breaking some forms of type annotations in base classes.

  • Windows: Allow selecting --msvc-version when a MSVC prompt is currently activated.

  • Windows: Do not fallback to using gcc when --msvc-version has been specified. Instead it’s an error if that fails to work.

  • Python3.6+: Added support for del () statements, these have no effect, but were crashing Nuitka.

    del a  # standard form
    del a, b  # same as del a; del b
    del (a, b)  # braces are allowed
    del ()  # allowed for consistency, but wasn't working.
  • Standalone: Added support for glfw through a dedicated plugin.

  • macOS: Added support for Python3 from system and CPython official download for latest OS version.

New Features

  • UI: With tqdm installed alongside Nuitka, experimental progress bars are enabled. Do not use `` –show-progress`` or --verbose as these might have to disable it.

  • Plugins: Added APIs for final processing of the result and onefile post processing.

  • Onefile: On Windows, the Python process terminates with KeyboardInterrupt when the user sends CTRL-break, CTRL-C, shutdown or logoff signals.

  • Onefile: On Windows, in case of the launching process terminating unexpectedly, e.g. due to Taskmanager killing it, or a os.sigkill resulting in that, the Python process still terminates with KeyboardInterrupt.

  • Windows: Now can select icons by index from files with multiple icons.


  • Avoid global passes caused by module specific optimization. The variable completeness os now traced per module and function scope, allowing a sooner usage. Unused temporary variables and closure variables are remove immediately. Recognizing possible auto releases of parameter variables is also instantly.

    This should bring down current passes from 5-6 global passes to only 2 global passes in the normal case, reducing frontend compile times in some cases massively.

  • Better unary node handling. Dedicated nodes per operation allow for more compact memory usage and faster optimization.

  • Detect flow control and value escape for the repr of node based on type shape.

  • Enhanced optimization of caught exception references, these never raise or have escapes of control flow.

  • Exception matching operations are more accurately annotated, and may be recognized to not raise in more cases.

  • Added optimization for the issubclass built-in.

  • Removed scons caching as used on Windows entirely. We should either be using clcache or ccache automatically now.

  • Make sure to use __slots__ for all node classes. In some cases, mixins were preventing the feature from being it. We now enforce their correct specification of slots, which makes sure we can’t miss it anymore. This should again gain more speed and save memory at frontend compile time.

  • Scons: Enhanced gcc version detection with improved caching behavior, this avoids querying the same gcc binary twice.


  • The description of Nuitka on PyPI was absent for a while. Added back by adding long description of the project derived from the README file.

  • Avoid terms blacklist, whilelist and slave in the Nuitka code preferring blocklist, ignorelist and child instead, which are actually more clear anyway. We follow a general trend to do this.

  • Configured the inline copy of Scons so pylance has an easier time to find it.

  • The git commit hook had stopped applying diffs with newest git, improved that.

  • Updated description for adding new CPython test suite.

  • Using https URLs for downloading dependency walker, for it to be more secure.

  • The commit hook can now be disabled, it’s in the Developer Manual how to do it.


  • Moved unary operations to their own module, the operators module was getting too crowded.

  • The scons files for Python C backend and Windows onefile got cleaned up some more and moved more common code to shared modules.

  • When calling external tools, make sure to provide null input where possible.

  • Unified calling install_name_tool into a single method for adding rpath and name changes both at the same time.

  • Unified how tools like readelf, ldconfig etc. are called and error exits and outputs checked to make sure we don’t miss anything as easily.


  • Adapted for some openSUSE specific path usages in standalone tests.

  • Basic tests for onefile operation and with termination signal sent were added.


The big changes in this release are the optimization changes to reduce the global passes and the memory savings from other optimization. These should again make Nuitka more scalable with large projects, but there definitely is work remaining.

Adding nice stopping behaviour for the Onefile mode on Windows is seemingly a first, and it wasn’t easy, but it will make it more reliable to users.

Also tooling of gcc and MSVC on Windows got a lot more robust, covering more cases, and macOS support has been renewed and should be a lot better now.

The progress bar is a nice touch and improves the overall feel of the compilation process, but obviously we need to aim at getting faster overall still. For projects using large dependencies, e.g. Pandas the compilation is still far too slow and that will need work on caching frontend results, and better optimization and C code generation for the backend.

Nuitka Release 0.6.11

This release is a massive improvement in many ways with lots of bug fixes and new features.

Bug Fixes

  • Fix, the .pyi file parser didn’t handle relative imports. Fixed in already.

  • Windows: Fix, multiprocessing plugin was not working reliable following of imports from the additional entry point. Fixed in already.

  • Pipenv: Workaround parsing issue with our to allow installation from GitHub. Fixed in already.

  • Merging of branches in optimization could give nondeterministic results leading to more iterations than necessary. Fixed in already.

  • Windows: Avoid profile powershell when attempting to resolve symlinks. Fixed in already.

  • Windows: Fix, always check for stdin, stdout, and stderr presence. This was so far restricted to gui mode applications, but it seems to be necessary in other situations too. Fixed in already.

  • Python2: Fix, --trace-execution was not working for standalone mode but can be useful for debugging. Fixed in already.

  • Windows: Onefile could run into path length limits. Fixed in already.

  • Windows: The winlib gcc download link became broken and was updated. Fixed in already.

  • Plugins: The “__main__” module was not triggering all plugin hooks, but it needs to for completeness.

  • Standalone: Fix, symlinked Python installations on Windows were not working, with dependency walker being unable to look into these. Fixed in already.

  • Standalone: Fix support for numpy on Windows and macOS, the plugin failed to copy important DLLs. Fixed in already.

  • Python3: For versions before 3.7, the symlink resolution also needs to be done, but wasn’t handling the bytes output yet. Fixed in already.

  • Fix, folder based inclusion would both pick up namespace folders and modules of the same name, crashing the compilation due to conflicts. Fixed in already.

  • Fix, the --lto wasn’t used for clang on non-Windows yet.

  • Fix, the order of locals dict releases wasn’t enforced, which could lead to differences that break caching of C files potentially. Fixed in already.

  • Fix, hash nodes didn’t consider if their argument was raising, even if the type of the argument was str and therefore the operation should not. Fixed in already.

  • Fix, need to copy type shape and escape description for the replacement inverted comparisons when used with not, otherwise the compilation can crash as these are expected to be present at all times. Fixed in already.

  • Fix, some complex constant values could be confused, e.g. -0j and 0j. These corner cases were not properly considered in the constant loading code, only for float so far.

  • Standalone: Fix, bytecode only standard library modules were not working. This is at least used with Fedora 33.

  • Linux: Fix, extension modules compiled with --lto were not working.

  • Windows: Retry if updating resources fails due to Virus checkers keeping files locked.

  • Plugins: Pre- and postload code of modules should not be allowed to cause ImportError, as these will be invisible to the other parts of optimization, instead make them unraisable error traces.

  • Standalone: Adding missing import for SciPy 1.6 support.

  • Windows: Fix, only export required symbols when using MinGW64 in module mode.

New Features

  • Python3.9: Added official support for this version.

  • Onefile: Added command line options to include data files. These are --include-package-data which will copy all non-DLLs and non-Python files of package names matching the pattern given. And --include-data-file takes source and relative target file paths and copies them. For onefile this is the only way to include files, for standalone mode they are mostly a convenience function.

  • Onefile: Added mode where the file is unpacked to a temporary folder before running instead of doing it to appdata.

  • Onefile: Added linux specific options --linux-onefile-icon to allow provision of an icon to use in onefile mode on Linux, so far this was only available as the hard coded path to a Python icon, which also didn’t exist on all platforms.

  • UI: Major logging cleanup. Everything is now using our tracing classes and even error exits go through there and are therefore colored if possible.

  • Plugins: Make it easier to integrate commercial plugins, now only an environment variable needs to point to them.

  • UI: Enhanced option parsing gives notes. This complains about options that conflict or that are implied in others. Trying to catch more usage errors sooner.

  • Plugins: Ignore exceptions in buggy plugin code, only warn about them unless in debug mode, where they still crash Nuitka.

  • Scons: More complete scons report files, includes list values as well and more modes used.

  • Windows: The clcache is now included and no longer used from the system.

  • Output for clcache and ccache results got improved.

  • Enhanced support for clang, on Windows if present near a gcc.exe like it is the case for some winlibs downloads, it will be used. To use it provide --mingw64 --clang both. Without the first one, it will mean clangcl.exe which uses the MSVC compiler as a host.


  • Some modules had very slow load times, e.g. if they used many list objects due to linear searches for memory deduplication of objects. We now have dictionaries of practically all constant objects loaded, making these more instant.

  • Use less memory at compile time due using __slots__ for all node types, finally figured out, how to achieve this with multiple inheritance.

  • Use hedley for compiler macros like unlikely as they know best how to do these.

  • Special case the merging of 2 branches avoiding generic code and being much faster.

  • Hard imports have better code generated, and are being optimized into for the few standard library modules and builtin modules we handle, they also now annotate the type shape to be module.

  • No longer annotate hard module import attribute lookups as control flow escapes. Not present attributes are changed into static raises. Trust for values is configured for a few values, and experimental.

  • Avoid preloaded packages for modules that have no side effects and are in the standard library, typically .pth files will use e.g. os but that’s not needed to be preserved.

  • Use incbin for including binary data through inline assembly of the C compiler. This covers many more platforms than our previous linker option hacks, and the fallback to generated C code. In fact everything but Windows uses this now.


  • Windows: For Scons we now require a Python 3.5 or higher to be installed to use it.

  • Windows: Removed support for gcc older than version 8. This specifically affects CondaCC and older MinGW64 installations. Since Nuitka can now download the MinGW64 10, there is no point in having these and they cause issues.

  • We took over the maintenance of clcache as Nuitka/clcache which is not yet ready for public consumption, but should become the new source of clache in the future.

  • Include an inline copy of clcache in Nuitka and use it on Windows for MSVC and ClangCL.

  • Removed compatibility older aliases of follow option, --recurse-* and require --follow-* options to be used instead.

  • For pylint checking, the tool now supports a --diff mode where only the changed files get checked. This is much faster and allows to do it more often before commit.

  • Check the versions of isort and black when doing the auto-format to avoid using outdated versions.

  • Handling missing pylint more gracefully when checking source code quality.

  • Make sure to use the codespell tool with Python3 and make sure to error exit when spelling problems were found, so we can use this in GitHub actions too.

  • Removed Travis config, we now only use GitHub actions.

  • Removed landscape config, it doesn’t really exist anymore.

  • Bumped all PyPI dependnecies to their latest versions.

  • Recommend ccache on Debian, as we now consider the absence of ccache something to warn about.

  • Plugins: The DLLs asked for by plugins that are not found are no longer warned about.

  • Allow our checker and format tools to run on outside of tree code. We are using that for Nuitka/clcache.

  • Added support for Fedora 33 and openSUSE 15.3, as well as Ubuntu Groovy.

  • Windows: Check if Windows SDK is installed for MSVC and ClangCL.

  • Windows: Enhanced wording in case no compiler was found. No longer tell people how to manually install MinGW64, that is no longer necessary and pywin32 is not needed to detect MSVC, so it’s not installed if not found.

  • Detect “embeddable Python” by missing include files, and reject it with proper error message.

  • Added onefile and standalone as a use case to the manual and put also the DLL and data files problems as typically issues.


  • Avoid decimal and string comparisons for Python versions checks, these were lazy and are going to break once 3.10 surfaces. In testing we now use tuples, in Nuitka core hexacimal values much like CPython itself does.

  • Stop using subnode child getters and setters, and instead only use subnode attributes. This was gradually changed so far, but in this release all remaining uses have migrated. This should also make the optimization stage go faster.

  • Change node constructors to not use a decorator to resolve conflicts with builtin names, rather handle these with manual call changes, the decorator only made it difficult to read and less performant.

  • Move safe string helpers to their own dedicated helper file, allowing for reuse in plugin code that doesn’t want to use all of Nuitka C helpers.

  • Added utils code for inline copy imports, as we use that for quite a few things now.

  • Further restructured the Scons files to use more common code.

  • Plugins: The module name objects now reject many str specific APIs that ought to not be used, and the code got changed to use these instead, leading to cleaner and more correct usages.

  • Using named tuples to specify included data files and entry points.

  • Use pkgutil in plugins to scan for modules rather than listing directories.


  • New option to display executed commands during comparisons.

  • Added test suite for onefile testing.


This release has seen Python3.9 and Onefile both being completed. The later needs compression added on Windows, but that can be added in a coming release, for now it’s fully functional.

The focus clearly has been on massive cleanups, some of which will affect compile time performance. There is relatively little new optimization otherwise.

The adoption of clcache enables a very fast caching, as it’s now loaded directly into the Scons process, avoiding a separate process fork.

Generally a lot of polishing has been applied with many cleanups lowering the technical debt. It will be interesting to see where the hard module imports can lead us in terms of more optimization. Static optimization of the Python version comparisons and checks is needed to lower the amount of imports to be processed.

Important fixes are also included, e.g. the constants loading performance was too slow in some cases. The multiprocessing on Windows and numpy plugins were regressed and finally everything ought to be back to working fine.

Future work will have to aim at enhanced scalability. In some cases, Nuitka still takes too much time to compile if projects like Pandas include virtually everything installed as an option for it to use.

Nuitka Release 0.6.10

This release comes with many new features, e.g. onefile support, as well as many new optimization and bug fixes.

Bug Fixes

  • Fix, was memory leaking arguments of all complex call helper functions. Fixed in already.

  • Plugins: Fix, the dill-compat code needs to follow API change. Fixed in already.

  • Windows: Fixup for multiprocessing module and complex call helpers that could crash the program. Fixed in already.

  • Fix, the frame caching could leak memory when using caching for functions and generators used in multiple threads.

  • Python3: Fix, importing an extension module below a compiled module was not possible in accelerated mode.

  • Python3: Fix, keyword arguments for open built-in were not fully compatible.

  • Fix, the scons python check should also not accept directories, otherwise strange misleading error will occur later.

  • Windows: When Python is installed through a symbolic link, MinGW64 and Scons were having issues, added a workaround to resolve it even on Python2.

  • Compatibility: Added support for co_freevars in code objects, e.g. newer matplotlib needs this.

  • Standalone: Add needed data files for gooey. Fixed in already.

  • Scons: Fix, was not respecting --quiet option when running Scons. Fixed in already.

  • Scons: Fix, wasn’t automatically detecting Scons from promised paths. Fixed in already.

  • Scons: Fix, the clcache output parsing wasn’t robust enough. Fixed in already.

  • Python3.8: Ignore all non-strings provided in doc-string fashion, they are not to be considered.

  • Fix, getattr, setattr and hasattr could not be used in finally clauses anymore. Fixed in already.

  • Windows: For Python3 enhanced compatibility for Windows no console mode, they need a sys.stdin or else e.g. input will not be compatible and raise RuntimeError.

New Features

  • Added experimental support for Python 3.9, in such a way that the CPython3.8 test suite passes now, the 3.9 suite needs investigation still, so we might be missing new features.

  • Added experimental support for Onefile mode with --onefile that uses AppImage on Linux and our own bootstrap binary on Windows. Other platforms are not supported at this time. With this, the standalone folder is packed into a single binary. The Windows variant currently doesn’t yet do any compression yet, but the Linux one does.

  • Windows: Added downloading of ccache.exe, esp. as the other sources so far recommended were not working properly after updates. This is taken from the official project and should be good.

  • Windows: Added downloading of matching MinGW64 C compiler, if no other was found, or that was has the wrong architecture, e.g. 32 bits where we need 64 bits.

  • Windows: Added ability to copy icon resources from an existing binary with new option --windows-icon-from-exe.

  • Windows: Added ability to provide multiple icon files for use with different desktop resolutions with new option --windows-icon-from-ico that got renamed to disambiguate from other icon options.

  • Windows: Added support for requesting UAC admin right with new option --windows-uac-admin.

  • Windows: Added support for requesting “uiaccess” rights with yet another new option --windows-uac-uiaccess.

  • Windows: Added ability to specify version info to the binary. New options --windows-company-name, --windows-product-name, --windows-file-version, --windows-product-version, and --windows-file-description have been added. Some of these have defaults.

  • Enhanced support for using the Win32 compiler of MinGW64, but it’s not perfect yet and not recommended.

  • Windows: Added support for LTO mode for MSVC as well, this seems to allow more optimization.

  • Plugins: The numpy plugin now handles matplotlib3 config files correctly.


  • Use less C variables in dictionary created, not one per key/value pair. This improved scalability of C compilation.

  • Use common code for module variable access, leading to more compact code and enhanced scalability of C compilation.

  • Use error exit during dictionary creation to release the dictionary, list, tuple, and set in case of an error occurring while they are still under construction. That avoids releases of it in error exists, reducing the generated code size by a lot. This improves scalability of C compilation for generating these.

  • Annotate no exception raise for local variables of classes with know dict shape, to avoid useless error exits.

  • Annotate no exception exit for staticmethod and classmethod as they do not check their arguments at all. This makes code generated for classes with these methods much more compact, mainly improving their scalability in C compilation.

  • In code generation, prefer bool over nuitka_bool which allows to annotate exception result, leading to more compact code. Also cleanup so that code generation always go through the C type objects, rather than doing cases locally, adding a C type for bool.

  • Use common code for C code handling const None return only, to cases where there is any immutable constant value returned, avoid code generation for this common case. Currently mutable constants are not handled, this may be added in the future.

  • Annotate no exception for exception type checks in handlers for Python2 and no exception if the value has exception type shape for Python3. The exception type shape was newly added. This avoids useless exception handlers in most cases, where the provided exception is just a built-in exception name.

  • Improve speed of often used compile time methods on nodes representing constant values, by making their implementation type specific to improve frontend compile time speed, we check e.g. mutable and hashable a lot.

  • Provide truth value for variable references, enhancing loop optimization and merge value tracing, to also decide this correctly for values only read, and then changed through attribute, e.g. append on lists. This allows many more static optimization.

  • Use staticmethod for methods in Nuitka nodes to achieve faster frontend compile times where possible.

  • Use dedicated helper code for calls with single argument, avoiding the need have a call site local C array of size one, just to pass a pointer to it.

  • Added handling of hash slot, to predict hashable keys for dictionary and sets.

  • Share more slot provision for built-in type shapes from mixin classes, to get them more universally provided, even for special types, where their consideration is unusual.

  • Trace “user provided” flag only for constants where it really matters, i.e. for containers and generally potentially large values, but not for every number or boolean value.

  • Added lowering of bytearray constant values to bytes value iteration, while handling constant values for this optimization with dedicated code for improved frontend compilation speed.

  • The dict built-in now annotates the dictionary type shape of its result.

  • The wrapping side-effects node now passes on the type shape of the wrapped value, allowing for optimization of these too.

  • Split slice nodes into variants with 1, 2 or 3 arguments, to avoid the overhead of determining which case we have, as well as to save a bit of memory, since these are more frequently used on Python3 for subscript operations. Also annotate their type shape, allowing more optimization.

  • Faster dictionary lookups, esp. in cases where errors occur, because we were manually recreating a KeyError that is already provided by the dict implementation. This should also be faster, as it avoids a CPython API call overhead on the DLL and they can provide a reference or not for the returned value, simplifying using code.

  • Faster dictionary containment checks, with our own dedicated helper, we can use code that won’t create an exception when an item is not present at all.

  • Faster hash lookups with our own helper, separating cases where we want an exception for non-hashable values or not. These should also be faster to call.

  • Avoid acquiring thread state in exception handling that checks if a StopIteration occurred, to improved speed on Python3, where is involves locking, but this needs to be applied way more often.

  • Make sure checks to debug mode and full compatibility mode are done with the variables introduced, to avoid losing performance due to calls for Nuitka compile time enhancements. This was so far only done partially.

  • Split constant references into two base classes, only one of them tracking if the value was provided by the user. This saves compile time memory and avoids the overhead to check if sizes are exceeded in cases they cannot possibly be so.

  • The truth value of container creations is now statically known, because the empty container creation is no longer a possibility for these nodes, allowing more optimization for them.

  • Optimize the bool built-in with no arguments directory, allow to simplify the node for single argument form to avoid checks if an argument was given.

  • Added iteration handles for xrange values, and make them faster to create by being tied to the node type, avoiding shared types, instead using the mixin approach. This is in preparation to using them for standard iterator tracing as well. So far they are only used for any and all decision.

  • Added detection if a iterator next can raise, using existing iterator checking which allows to remove needless checks and exception traces. Adding a code variant for calls to next that cannot fail, while tuning the code used for next and unpacking next, to use faster exception checking in the C code. This will speed up unpacking performance for some forms of unpacking from known sizes.

  • Make sure to use the fastest tuple API possible in all of Nuitka, many place e.g. used PyTuple_Size, and one was in a performance critical part, e.g. in code that used when compiled functions as called as a method.

  • Added optimized variant for _PyList_Extend for slightly faster unpacking code.

  • Added optimized variant for PyList_Append for faster list contractions code.

  • Avoid using RemoveFileSpec and instead provide our own code for that task, slightly reducing file size and avoiding to use the Shlapi link library.


  • Made reflected test use common cleanup of test folder, which is more robust against Windows locking issues.

  • Only output changed CPython output after the forced update of cached value was done, avoiding duplicate or outdated outputs.

  • Avoid complaining about exceptions for in-place operations in case they are lowered to non-inplace operations and then raise unsupported, not worth the effort to retain original operator.

  • Added generated test for subscript operations, also expanding coverage in generated tests by making sure, conditional paths are both taken by varying the cond value.

  • Use our own code helper to check if an object has an attribute, which is faster, because it avoids creating exceptions in the first place, instead of removing them afterwards.


  • Make sure that code generation always go through the C type objects rather than local elif casing of the type. This required cleaning up many of the methods and making code more abstract.

  • Added base class for C types without reference counting, so they can share the code that ignores their handling.

  • Remove getConstant for constant value nodes, use the more general getCompileTimeConstant instead, and provide quick methods that test for empty tuple or dict, to use for checking concrete values, e.g. with call operations.

  • Unified container creation into always using a factory function, to be sure that existing container creations are not empty.

  • Stop using @calledWithBuiltinArgumentNamesDecorator where possible, and instead make explicit wrapping or use correct names. This was used to allow e.g. an argument named list to be passed from built-in optimization, but that can be done in a cleaner fashion. Also aligned no attributes and the argument names, there was inconsistency there.

  • Name mangling was done differently for attribute names and normal names and with non-shared code, and later than necessary, removing this as a step from variable closure taking after initial tree build.

  • As part of the icon changes, now handled in Python code, we stop using the rc binary and handle all resources ourselves, allowing to remove that code from the Scons side of things.

  • Moved file comparison code of standalone mode into file utils function for use in plugins as well.

  • Unified how path concatenation is done in Nuitka helper code, there were more or less complete variants, this is making sure, the most capable form is used in all cases.

  • Massive cleanup to our scons file, by moving out util code that only scons uses, hacks we apply to speed up scons, and more to separate modules with dedicated interfaces.

  • When using enumerate we now provide start value of 1 where it is appropriate, e.g. when counting source code lines, rather than adding count+1 on every usage, making code more readable.


  • Do not recommend Anaconda on Windows anymore, it seems barely possible to get anything installed on it with a fresh download, due to the resolver literally working for days without finishing, and then reporting conflicts, it would only we usable when starting with Miniconda, but that seems less interesting to users, also gcc 5.2 is way too old these days.

  • The commit hook should be reinstalled, since it got improved and adapted for newer git versions.

  • Added link to donations to funding document, following a GitHub standard.

  • Bumped requirements for development to the latest versions, esp. newer isort.

  • Added a rough description of tests to do to add a new CPython test suite, to allow others to take this task in the future.

  • Updated the git hook so that Windows and newest git works.

  • Make it more clear in the documentation that Microsoft Appstore Python is not supported.


This is the big release in terms of scalability. The optimization in this release mostly focused on getting things that cause increased compile times sorted out. A very important fix avoids loop optimization to leak into global passes of all modules unnecessarily, but just as important, generated code now is much better for the C compiler to consume in observed problematic cases.

More optimization changes are geared towards reducing Nuitka frontend compile time, which could also be a lot in some cases, ending up specializing more constant nodes and how they expose themselves to optimization.

Other optimization came from supporting Python 3.9 and things come across during the implementation of that feature, e.g. to be able to make differences with unpacking error messages, we provide more code to handle it ourselves, and to manually optimize how to interact with e.g. list objects.

For Windows, the automatic download of ccache and a matching MinGW64 if none was found, is a new step, that should lower the barrier of entry for people who have no clue what a C compiler is. More changes are bound to come in this field with future releases, e.g. making a minimum version requirement for gcc on Windows that excludes unfit C compilers.

All in all, this release should be taken as a major cleanup, resolving many technical debts of Nuitka and preparing more optimization to come.

Nuitka Release 0.6.9

This releases contains important bug fixes for regressions of the 0.6.8 series which had relatively many problems. Not all of these could be addressed as hotfixes, and other issues were even very involved, causing many changes to be necessary.

There are also many general improvements and performance work for tracing and loops, but the full potential of this will not be unlocked with this release yet.

Bug Fixes

  • Fix, loop optimization sometimes didn’t determinate, effectively making Nuitka run forever, with no indication why. This has been fixed and a mechanism to give up after too many attempts has been added.

  • Fix, closure taking object allowed a brief period where the garbage collector was exposed to uninitialized objects. Fixed in already.

  • Python3.6+: Fix corruption for exceptions thrown into asyncgen. Fixed in already.

  • Fix, deleting variables detected as C type bool could raise an UnboundLocalError that was wrong. Fixed in already.

  • Python3.8.3+: Fix, future annotations parsing was using hard coded values that were changed in CPython, leading to errors.

  • Windows: Avoid encoding issues for Python3 on more systems, by going from wide characters to unicode strings more directly, avoiding an encoding as UTF-8 in the middle. Fixed in already.

  • Windows: Do not crash when warning about uninstalled MSVC using Python3. This is a Scons bug that we fixed. Fixed in already.

  • Standalone: The output of dependency walker should be considered as “latin1” rather than UTF-8. Fixed in already.

  • Standalone: Added missing hidden dependencies for flask. Fixed in already.

  • Standalone: Fixed win32com.client on Windows. Fixed in already.

  • Standalone: Use pkgutil to scan encoding modules, properly ignoring the same files as Python does in case of garbage files being there. Fixed in already.

  • Plugins: Enabling a plugin after the filename to compile was given, didn’t allow for arguments to the passed, causing problems. Fixed in already.

  • Standalone: The certifi data file is now supported for all modules using it and not only some.

  • Standalone: The bytecode for the standard library had filenames pointing to the original installation attached. While these were not used, but replaced at run time, they increased the size of the binary, and leaked information.

  • Standalone: The path of sys.executable was not None, but pointing to the original executable, which could also point to some temporary virtualenv directory and therefore not exist, also it was leaking information about the original install.

  • Windows: With the MSVC compiler, elimination of duplicate strings was not active, causing even unused strings to be present in the binary, some of which contained file paths of the Nuitka installation.

  • Standalone: Added support for pyglet.

  • Plugins: The command line handling for Pmw plugin was using wrong defaults, making it include more code than necessary, and to crash if it was not there.

New Features

  • Windows: Added support for using Python 2.7 through a symlink too. This was already working for Python3, but a scons problem prevented this from working.

  • Caching of compiled C files is now checked with ccache and clcache, and added automatically where possible, plus a report of the success is made. This can accelerate the re-compile very much, even if you have to go through Nuitka compilation itself, which is not (yet) cached.

  • Added new --quiet option that will disable informational traces that are going to become more.

  • The Clang from MSVC installation is now picked up for both 32 and 64 bits and follows the new location in latest Visual Studio 2019.

  • Windows: The ccache from Anaconda is now supported as well as the one from msys64.


  • The value tracing has become more correct with loops and in general less often inhibits optimization. Escaping of value traces is now a separate trace state allowing for more appropriate handling of actual unknowns.

  • Memory used for value tracing has been lowered by removing unnecessary states for traces, that we don’t use anymore.

  • Windows: Prevent scons from scanning for MSVC when asked to use MinGW64. This avoids a performance loss doing something that will then end up being unused.

  • Windows: Use function level linking with MSVC, this will allow for smaller binaries to be created, that don’t have to include unused helper functions.


  • The scons file now uses Nuitka utils functions and is itself split up into several modules for enhanced readability.

  • Plugin interfaces for providing extra entry points have been cleaned up and now named tuples are used. Backward compatibility is maintained though.


  • The use of the logging module was replaced with more of our custom tracing and we now have the ability to write the optimization log to a separate file.

  • Old style plugin options are now detected and reported as a usage error rather than unknown plugin.

  • Changed submodules to use git over https, so as to not require ssh which requires a key registered and causes problems with firewalls too.

  • More correct Debian copyright file, made formatting of emails in source code consistent.

  • Added repository for Ubuntu focal.


The main focus of this release has been bug fixes with only a little performance work due to the large amount of regressions and other findings from the last release.

The new constants loading for removes a major scalability problem. The checked and now consistently possible use of ccache and clcache allows for much quicker recompilation. Nuitka itself can still be slow in some cases, but should have seen some improvements too. Scalability will have to remain a focus for the next releases too.

The other focus, was to make the binaries contain no original path location, which is interesting for standalone mode. Nuitka should be very good in this area now.

For optimization, the new loop code is again better. But it was also very time consuming, to redo it, yet again. This has prevented other optimization to be added.

And then for correctness, the locals scope work, while very invasive, was necessary, to handle the usage of locals inside of contractions, but also will be instrumental for function inlining to become generally available.

So, ultimately, this release is a necessary intermediate step. Upcoming releases will be able to focus more clearly on run time performance again as well as on scalability for generated C code.

Nuitka Release 0.6.8

This releases contains important general improvements and performance improvements and enhanced optimization as well as many bug fixes that enhance the Python 3.8 compatibility.

Bug Fixes

  • Python3.5+: Fix, coroutines and asyncgen could continue iteration of awaited functions, even after their return, leading to wrong behaviour.

  • Python3.5+: Fix, absolute imports of names might also refer to modules and need to be handled for module loading as well.

  • Fix, the fromlist of imports could loose references, potentially leading to corruption of contained strings.

  • Python3.8: Fix, positional only arguments were not enforced to actually be that way.

  • Python3.8: Fix, complex calls with star arguments that yielded the same value twice, were not yet caught.

  • Python3.8: Fix, evaluation order for nested dictionary contractions was not followed yet.

  • Windows: Use short paths, these work much better to load extension modules and TCL parts of TkInter cannot handle unicode paths at all. This makes Nuitka work in locations, where normal Python cannot.

  • Windows: Fixup dependency walker in unicode input directories.

  • Standalone: Use frozen module loader only at libpython initialisation and switch to built-in bytecode loader that is more compatible afterwards, increasing compatibility.

  • Standalone: Fix for pydantic support.

  • Standalone: Added missing hidden dependency of uvicorn.

  • Fix, the parser for .pyi files couldn’t handle multiline imports.

  • Windows: Derive linker arch of Python from running binary, since it can happen that the Python binary is actually a script.

  • Fixup static linking with libpython.a that contains main.o by making our colliding symbols for Py_GetArgcArgv weak.

  • Python3.7: Fix misdetection as asyncgen for a normal generator, if the iterated value is async.

  • Distutils: Fix build_nuitka for modules under nested namespaces.

  • OpenBSD: Follow usage of clang and other corrections to make accelerated mode work.

  • macOS: Fixup for standalone mode library scan.

  • Fix, the logging of --show-modules was broken.

  • Windows: Enable /bigobj mode for MSVC for large compilations to work.

  • Windows: Fixup crash in warning with pefile dependency manager.

  • Windows: Fixup win32com standalone detection of other Python version win32com is in system PATH.

  • Fix, the python flag for static hashes didn’t have the intended effect.

  • Fix, generators may be resurrected in the cause of their destruction, and then must not be released.

  • Fix, method objects didn’t implement the methods __reduce__ and __reduce_ex__ necessary for pickling them.

  • Windows: Fix, using a Python installation through a symlink was not working.

  • Windows: Fix, icon paths that were relative were not working anymore.

  • Python3.8: Detect duplicate keywords yielded from star arguments.

  • Fix, methods could not be pickled.

  • Fix, generators, coroutines and asyncgen might be resurrected during their release, allow for that.

  • Fix, frames need to traverse their attached locals to be released in some cases.

New Features

  • Plugin command line handling now allows for proper optparse options to be used, doing away with special parameter code for plugins. The arguments now also become automatically passed to the instantiations of plugins.

    Loading and creation of plugins are now two separate phases. They are loaded when they appear on the command line and can add options in their own group, even required ones, but also with default values.

  • Started using logging with name-spaces. Applying logging per plugin to make it easier to recognize which plugin said what. Warnings are now colored in red.

  • Python3.5+: Added support for two step module loading, making Nuitka loading even more compatible.

  • Enhanced import tracing to work on standalone binaries in a useful manner, allow to compare with normal binaries.

  • Fix, the setattr built-in was leaking a reference to the None value.


  • Proper loop SSA capable of detecting shapes with an incremental initial phase and a final result of alternatives for variables written in the loop. This detects shapes of manual integer incrementing loops correctly now, it doesn’t see through iterators yet, but this will come too.

  • Added type shapes for all operations and all important built-in types to allow more compile time optimization and better target type selection.

  • Target type code generation was expanded from manual usage with conditions to all operations allowing to get at bool target values more directly.

  • For in-place operations, there is the infrastructure to generate them for improved performance, but so far it’s only used for Python2 int, and not for the many types normal operations are supported.

  • Force usage of C boolean type for all indicator variables from the re-formulation. In some cases, we are not yet there with detections, and this gives instant benefit.

  • Complex constants didn’t annotate their type shape, preventing compile time optimization for them.

  • Python3.8: Also support vectorcall for compiled method objects. These are rarely used in new Python, but can make a difference.

  • Remove loops that have only a final break. This happens in static optimization in some cases, and allows more optimization to be done.

  • Avoid using a preparing a constant tuple value for calls with only constant arguments.

  • Avoid using PyErr_Format where it’s not necessary by adding specialized helpers for common cases.

  • Detect del statements that will raise an exception and replace with that.

  • Exception matching is boolean shape, allowing for faster code generation.

  • Disable recursion checks outside of full compat mode.

  • Avoid large blocks for conditional statements that only need to enclose the condition evaluation.

  • Added shortcuts for interactions between compiled generator variants, to avoid calls to their C methods with argument passing, etc.


  • Updated Developer Manual with changes that happened, removing the obsolete language choice section.

  • Added 3.8 support mentions in even more places.

  • The mailing list has been deleted. We now prefer Gitter chat and GitHub issues for discussions.

  • Visual Code recommended extensions are now defined as such in the project configuration and you will be prompted to install them.

  • Visual Code environments for Py38 and Py27 were added for easier switch.

  • Catch usage of Python from the Microsoft App Store, it is not supported and seems to limit access to the Python installation for security reasons that make support impossible.

  • Make it clear that --full-compat should not be used in help output.

  • Added instructions for MSVC runtimes and standalone compilation to support Windows 7.

  • More complete listing of copyright holders for Debian.

  • Updated to newer black and PyLint.

  • Enhanced gcc version check, properly works with gcc 10 and higher.


  • Pylint cleanups for some of the tests.

  • Added test for loading of user plugins.

  • Removed useless outputs for search mode skipping non-matches.


  • Limit command line handling for multiprocessing module to when the plugin is actually used, avoiding useless code of Windows binaries.

  • Pylint cleanup also foreign code like oset and odict.

  • In preparation of deprecating the alternative, --enable-plugin has become the only form used in documentation and tests.

  • Avoid numeric pylint symbols more often.

  • Distutils: Cleanup module name for distutils commands, these are not actually enforced by distutils, but very ugly in our coding conventions.

  • The “cannot get here” code to mark unreachable code has been improved and no longer needs an identifier passed, but uses the standard C mechanism for that.

  • Removed accessors for lookup sources from nodes, allowing for faster usage and making sure, lookups are only done where needed.


This release is huge in terms of bugs fixed, but also extremely important, because the new loop SSA and type tracing, allows for many more specialized code usages. We now can trace the type for some loops to be specifically an integer or long value only, and will become able to generate code that avoids using Python objects, in these cases.

Once that happens, the performance will make a big jump. Future releases will have to consolidate the current state, but it is expected that at least an experimental addition of C type float or C long can be added, add to that iterator type shape and value analsis, and an actual jump in performance can be expected.

Nuitka Release 0.6.7

This release contains bug fixes and improvements to the packaging, for the RPM side as well as for Debian, to cover Python3 only systems as they are now becoming more common.

Bug Fixes

  • Compatibility: The value of __module__ for extension modules was not dependent into which package the module was loaded, it now is.

  • Anaconda: Enhanced detection of Anaconda for Python 3.6 and higher.

  • CentOS6: Detect gcc version to allow saving on macro memory usage, very old gcc didn’t have that.

  • Include Python3 for all Fedora versions where it works as well as for openSUSE versions 15 and higher.

  • Windows: Using short path names to interact with Scons avoids problems with unicode paths in all cases.

  • macOS: The usage of install_name_tool could sometimes fail due to length limits, we now increase it at link time.

  • macOS: Do not link against libpython for module mode. This prevented extension modules from actually being usable.

  • Python3.6: Follow coroutine fixes in our asyncgen implementation as well.

  • Fix, our version number handling could overflow with minor versions past 10, so we limited it for now.

New Features

  • Added support for Python 3.8, the experimental was already there and pretty good, but now added the last obscure features too.

  • Plugins can now provide C code to be included in the compilation.

  • Distutils: Added targets build_nuitka and install_nuitka to complement bdist_nuitka, so we support software other than wheels, e.g. RPM packaging that compiles with Nuitka.

  • Added support for lldb the Clang debugger with the --debugger mode.


  • Make the file prefix map actually work for gcc and clang, and compile files inside the build folder, unless we are running in debugger mode, so we use ccache caching across different compilations for at least the static parts.

  • Avoid compilation of __frozen.c in accelerated mode, it’s not used.

  • Prefer using the inline copy of scons over systems scons. The later will only be slower. Use the fallback to external scons only from the Debian packages, since there we consider it forbidden to include software as a duplicate.


  • Added recommended plugins for Visual Code, replacing the list in the Developer Manual.

  • Added repository for Fedora 30 for download.

  • Added repository for CentOS 8 for download.

  • Updated inline copy of Scons used for Python3 to 3.1.2, which is said to be faster for large compilations.

  • Removed Eclipse setup from the manual, it’s only infererior at this point and we do not use it ourselves.

  • Debian: Stop recommending PyQt5 in the package, we no longer use it for built-in GUI that was removed.

  • Debian: Bumped the standards version and modernized the packaging, solving a few warnings during the build.


  • Scons: Avoid to add Unix only include paths on Windows.

  • Scons: Have the static source code in a dedicated folder for clarity.


  • Added tests to GitHub Actions, for the supported Python versions for all of Linux, macOS and Windows, covering the later publicly for the first time. We use Anaconda on macOS for the tests now, rather than Homebrew.

  • Enable IO encoding to make sure we use UTF-8 for more test suites that actually need it in case of problems.

  • Comparing module outputs now handles segfaults by running in the debugger too.


This release adds full support for Python 3.8 finally, which took us a while, and it cleans up a lot on the packaging side. There aren’t that many important bug fixes, but it’s still nice to this cleaned up.

We have important actual optimization in the pipeline that will apply specialization to target types and for comparison operations. We expect to see actual performance improvements in the next release again.

Nuitka Release 0.6.6

This release contains huge amounts of crucial bug fixes all across the board. There is also new optimization and many organisational improvements.

Bug Fixes

  • Fix, the top level module must not be bytecode. Otherwise we end up violating the requirement for an entry point on the C level.

  • Fix, avoid optimizing calls with default values used. This is not yet working and needed to be disabled for now.

  • Python3: Fix, missing keyword only arguments were not enforced to be provided keyword only, and were not giving the compatible error message when missing.

  • Windows: Find win32com DLLs too, even if they live in sub folders of site-packages, and otherwise not found. They are used by other DLLs that are found.

  • Standalone: Fixup for problem with standard library module in most recent Anaconda versions.

  • Scons: Fix, was using CXXFLAGS and CPPFLAGS even for the C compiler, which is wrong, and could lead to compilation errors.

  • Windows: Make --clang limited to clang-cl.exe as using it inside a MinGW64 is not currently supported.

  • Standalone: Added support for using lib2to2.pgen.

  • Standalone: Added paths used by openSUSE to the Tcl/Tk plugin.

  • Python3.6+: Fix, the __main__ package was None, but should be "" which allows relative imports from itself.

  • Python2: Fix, compile time optimization of floor division was using normal division.

  • Python3: Fix, some run time operations with known type shapes, were falsely reporting error message with unicode or long, which is of course not compatible.

  • Fix, was caching parent package, but these could be replaced e.g. due to bytecode demotion later, causing crashes during their optimization.

  • Fix, the value of __compiled__ could be corrupted when being deleted, which some modules wrappers do.

  • Fix, the value of __package__ could be corrupted when being deleted.

  • Scons: Make sure we can always output the compiler output, even if it has a broken encoding. This should resolve MSVC issues on non-English systems, e.g. German or Chinese.

  • Standalone: Support for newest sklearn was added.

  • macOS: Added resolver for run time variables in otool output, that gets PyQt5 to work on it again.

  • Fix, floor division of run time calculations with float values should not result in int, but float values instead.

  • Standalone: Enhanced support for boto3 data files.

  • Standalone: Added support for osgeo and gdal.

  • Windows: Fix, there were issues with spurious errors attaching the constants blob to the binary due to incorrect C types provided.

  • Distutils: Fix, need to allow / as separator for package names too.

  • Python3.6+: Fix reference losses in asyncgen when throwing exceptions into them.

  • Standalone: Added support for dill.

  • Standalone: Added support for scikit-image and skimage.

  • Standalone: Added support for weasyprint.

  • Standalone: Added support for dask.

  • Standalone: Added support for pendulum.

  • Standalone: Added support for pytz and pytzdata.

  • Fix, --python-flags=no_docstrings no longer implies disabling the assertions.

New Features

  • Added experimental support for Python 3.8, there is only very few things missing for full support.

  • Distutils: Added support for packages that are in a namespace and not just top level.

  • Distutils: Added support for single modules, not only packages, by supporting py_modules as well.

  • Distutils: Added support for distinct namespaces.

  • Windows: Compare Python and C compiler architecture for MSVC too, and catch the most common user error of mixing 32 and 64 bits.

  • Scons: Output variables used from the outside, so the debugging is easier.

  • Windows: Detect if clang installed inside MSVC automatically and use it if requested via --clang option. This is only the 32 bits variant, but currently the easy way to use it on Windows with Nuitka.


  • Loop variables were analysed, but results were only available on the inside of the loop, preventing many optimization in these cases.

  • Added optimization for the abs built-in, which is also a numerical operator.

  • Added optimization for the all built-in, adding a new concept of iteration handle, for efficient checking that avoids looking at very large sequences, of which properties can still be known.

    all(range(1, 100000))  # no need to look at all of them
  • Added support for optimizing ImportError construction with keyword-only arguments. Previously only used without these were optimized.

    raise ImportError(path="lala", name="lele")  # now optimized
  • Added manual specialization for single argument calls, solving a TODO, as these will be very frequent.

  • Memory: Use single child form of node class where possible, the general class now raises an error if used with used with only one child name, this will use less memory at compile time.

  • Memory: Avoid list for non-local declarations in every function, these are very rare, only have it if absolutely necessary.

  • Generate more compact code for potential NameError exceptions being raised. These are very frequent, so this improves scalability with large files.

  • Python2: Annotate comparison of None with int and str types as not raising an exception.

  • Shared empty body functions and generators.

    One shared implementation for all empty functions removes that burden from the C compiler, and from the CPU instruction cache. All the shared C code does is to release its arguments, or to return an empty generator function in case of generator.

  • Memory: Added support for automatic releases of parameter variables from the node tree. These are normally released in a try finally block, however, this is now handled during code generation for much more compact C code generated.

  • Added specialization for int and long operations %, <<, >>, |, &, ^, **, @.

  • Added dedicated nodes for representing and optimizing based on shapes for all binary operations.

  • Disable gcc macro tracing unless in debug mode, to save memory during the C compilation.

  • Restored Python2 fast path for int with unknown object types, restoring performance for these.


  • Use dedicated ModuleName type that makes the tests that check if a given module name is inside a namespace as methods. This was hard to get right and as a result, adopting this fixed a few bugs and or inconsistent results.

  • Expand the use of nuitka.PostProcessing to cover all actions needed to get a runnable binary. This includes using install_name_tool on macOS standalone, as well copying the Python DLL for acceleration mode, cleaning the x bit for module mode. Previously only a part of these lived there.

  • Avoid including the definitions of dynamically created helper functions in the C code, instead just statically declare the ones expected to be there. This resolves Visual Code complaining about it, and should make life also easier for the compiler and caches like ccache.

  • Create more helper code in closer form to what clang-format does, so they are easier to compare to the static forms. We often create hard coded variants for few arguments of call functions, and generate them for many argument variations.

  • Moved setter/getter methods for Nuitka nodes consistently to the start of the node class definitions.

  • Generate C code much closer to what clang-format would change it to be.

  • Unified calling install_name_tool on macOS into one function that takes care of all the things, including e.g. making the file writable.

  • Debug output from scons should be more consistent and complete now.

  • Sort files for compilation in scons for better reproducible results.

  • Create code objects version independent, avoiding python version checks by pre-processor, hiding new stuff behind macros, that ignore things on older Python versions.


  • Added many more built-in tests for increased coverage of the newly covered ones, some of them being generic tests that allow to test all built-ins with typical uses.

  • Many tests have become more PyLint clean as a result of work with Visual Code and it complaining about them.

  • Added test to check PyPI health of top 50 packages. This is a major GSoC 2019 result.

  • Output the standalone directory contents for Windows too in case of a failure.

  • Added generated tests to fully cover operations on different type shapes and their errors as well as results for typical values.

  • Added support for testing against installed version of Nuitka.

  • Cleanup up tests, merging those for only Python 3.2 with 3.3 as we no longer support that version anyway.

  • Execute the Python3 tests for macOS on Travis too.


  • The donation sponsored machine called donatix had to be replaced due to hardware breakage. It was replaced with a Raspberry-Pi 4.

  • Enhanced plugin documentation.

  • Added description of the git workflow to the Developer Manual.

  • Added checker script check-nuitka-with-codespell that reports typos in the source code for easier use of codespell with Nuitka.

  • Use newest PyLint and clang-format.

  • Also check plugin documentation files for ReST errors.

  • Much enhanced support for Visual Code configuration.

  • Trigger module code is now written into the build directory in debug mode, to aid debugging.

  • Added deep check function that descends into tuples to check their elements too.


This release comes after a long time of 4 months without a release, and has accumulated massive amounts of changes. The work on CPython 3.8 is not yet complete, and the performance work has yet to show actual fruit, but has also progressed on all fronts. Connecting the dots and pieces seems not far away.

Nuitka Release 0.6.5

This release contains many bug fixes all across the board. There is also new optimization and many organisational improvements.

Bug Fixes

  • Python3.4+: Fixed issues with modules that exited with an exception, that could lead to a crash, dealing with their __spec__ value.

  • Python3.4+: The __loader__ method is_package had the wrong signature.

  • Python3.6+: Fix for async with being broken with uncompiled generators.

  • Python3.5+: Fix for coroutines that got their awaited object closed behind their back, they were complaining with RuntimeError should they be closed themselves.

  • Fix, constant values None in a bool target that could not be optimized away, lead to failure during code generation.

    if x() and None:
  • Standalone: Added support for sha224, sha384, sha512 in crypto package.

  • Windows: The icon wasn’t properly attached with MinGW64 anymore, this was a regression.

  • Windows: For compiler outputs, also attempt preferred locale to interpret outputs, so we have a better chance to not crash over MSVC error messages that are not UTF-8 compatible.

  • macOS: Handle filename collisions for generated code too, Nuitka now treats all filesystems for all OS as case insensitive for this purpose.

  • Compatibility: Added support for tolerant del in class exception handlers.

    class C:
        except Exception as e:
            del e
            # At exception handler exit, "e" is deleted if still assigned

    We already were compatible for functions and modules here, but due to the special nature of class variables really living in dictionaries, this was delayed. But after some other changes, it was now possible to solve this TODO.

  • Standalone: Added support for Python3 variant of Pmw.

  • Fix, the NumPy plugin now handles more installation types.

  • Fix, the qt plugin now handles multiple library paths.

  • Fix, need libm for some Anaconda variants too.

  • Fix, left over bytecode from plugins could crash the plugin loader.

  • Fix, pkgutil.iter_packages is now working for loaded packages.

New Features

  • Python3.8: Followed some of the changes and works with beta2 as a Python 3.7, but none of the new features are implemented yet.

  • Added support for Torch, Tensorflow, Gevent, Sklearn, with a new Nuitka plugin.

  • Added support for “hinted” compilation, where the used modules are determined through a test run.

  • Added support for including TCL on Linux too.


  • Added support for the any built-in. This handles a wide range of type shapes and constant values at compile time, while also having optimized C code.

  • Generate code for some CLONG operations in preparation of eventual per expression C type selection, it then will allow to avoid objects in many instances.

  • Windows: Avoid creating link libraries for MinGW64 as these have become unnecessary is the mean time.

  • Packages: Do not export entry points for all included packages, only for the main package name it is importable as.


  • Added support for Visual Studio 2019 as a C compiler backend.

  • Improved plugin documentation describing how to create plugins for Nuitka even better.

  • The is now a mode for running the tests called all which will execute all the tests and report their errors, and only fail at the very end. This doesn’t avoid wasting CPU cycles to report that e.g. all tests are broken, but it allows to know all errors before fixing some.

  • Added repository for Fedora 30 for download.

  • Added repository for openSUSE 15.1 for download.

  • Ask people to compile hello world program in the GitHub issue template, because many times, they have setup problems only.

  • Visual Studio Code is now the recommended IDE and has integrated configuration to make it immediately useful.

  • Updated internal copy of Scons to 3.1.0 as it incorporates many of our patches.

  • Changed wordings for optimization to use “lowering” as the only term to describe an optimization that simplifies.


  • Plugins: Major refactoring of Nuitka plugin API.

  • Plugins: To locate module kind, use core Nuitka code that handles more cases.

  • The test suite runners are also now auto-formatted and checked with PyLint.

  • The Scons file is now PyLint clean too.

  • Avoid build_definitions.h to be included everywhere, in that it’s only used in the main program part. This makes C linter hate us much less for using a non-existent file.


  • Run the tests using Travis on macOS for Python2 too.

  • More standalone tests have been properly whitelisting to cover openSSL usage from local system.

  • Disabled PySide2 test, it’s not useful to fail and ignore it.

  • Tests: Fixups for coverage testing mode.

  • Tests: Temporarily disable some checks for constants code in reflected tests as it only exposes marshal not being deterministic.


This release is huge again. Main points are compatibility fixes, esp. on the coroutine side. These have become apparently very compatible now and we might eventually focus on making them better.

Again, GSoC 2019 is also showing effects, and will definitely continue to do soin the next release.

Many use cases have been improved, and on an organisational level, the adoption of Visual Studio Code seems an huge improvement to have a well configured IDE out of the box too.

In upcoming releases, more built-ins will be optimized, and hopefully the specialization of operations will hit more and more code with more of the infrastructure getting there.

Nuitka Release 0.6.4

This release contains many bug fixes all across the board. There is also new optimization and many organisational improvements.

Bug Fixes

  • When linking very large programs or packages, with gcc compiler, Scons can produce commands that are too large for the OS. This happens sooner on the Windows OS, but also on Linux. We now have a workaround that avoids long command lines by using @sources.tmp syntax.

  • Standalone: Remove temporary module after its use, instead of keeping it in sys.modules where e.g. Quart code tripped over its __file__ value that is illegal on Windows.

  • Fixed non-usage of our enhanced detection of gcc version for compilers if given as a full path.

  • Fixed non-detection of gnu-cc as a form of gcc compiler.

  • Python3.4: The __spec__ value corrections for compiled modules was not taking into account that there was a __spec__ value, which can happen if something is wrapping imported modules.

  • Standalone: Added implicit dependencies for passlib.

  • Windows: Added workaround for OS command line length limit in compilation with MinGW64.

  • Python2: Revive the enum plugin, there are backports of the buggy code it tries to patch up.

  • Windows: Fixup handling of SxS with non zero language id, these occur e.g. in Anaconda.

  • Plugins: Handle multiple PyQt plugin paths, e.g. on openSUSE this is done, also enhanced finding that path with Anaconda on Windows.

  • Plugins: For multiprocessing on Windows, allow the .exe suffix to not be present, which can happen when ran from command line.

  • Windows: Better version checks for DLLs on Python3, the ctypes helper code needs more definitions to work properly.

  • Standalone: Added support for both pycryptodome and pycryptodomex.

  • Fix, the chr built-in was not giving fully compatible error on non number input.

  • Fix, the id built-in doesn’t raise an exception, but said otherwise.

  • Python3: Proper C identifiers for names that fit into latin-1, but are not ascii encodings.

New Features

  • Windows: Catch most common user error of using compiler from one architecture against Python from another. We now check those and compare it, and if they do not match, inform the user directly. Previously the compilation could fail, or the linking, with cryptic errors.

  • Distutils: Using setuptools and its runners works now too, not merely only pure distutils.

  • Distutils: Added more ways to pass Nuitka specific options via distutils.

  • Python3.8: Initial compatibility changes to get basic tests to work.


  • Nuitka is participating in the GSoC 2019 with 2 students, Batakrishna and Tommy.

  • Point people creating PRs to using the pre-commit hook in the template. Due to making the style issues automatic, we can hope to encounter less noise and resulting merge problems.

  • Many improvements to the pre-commit hook were done, hopefully completing its development.

  • Updated to latest pylint, black, and isort versions, also added codespell to check for typos in the source code, but that is not automated yet.

  • Added description of how to use experimental flags for your PRs.

  • Removed mirroring from Bitbucket and Gitlab, as we increasingly use the GitHub organisation features.

  • Added support for Ubuntu Disco, removed support for Ubuntu Artful packages.


  • Windows: Attach data blobs as Windows resource files directly for programs and avoid using C data files for modules or MinGW64, which can be slow.

  • Specialization of helper codes for + is being done for more types and more thoroughly and fully automatic with Jinja2 templating code. This does replace previously manual code.

  • Added specialization of helper codes for * operation which is entirely new.

  • Added specialization of helper codes for - operation which is entirely new.

  • Dedicated nodes for specialized operations now allow to save memory and all use type shape based analysis to predict result types and exception control flow.

  • Better code generation for boolean type values, removing error checks when possible.

  • Better static analysis for even more type operations.


  • Fixed many kinds of typos in the code base with codespell.

  • Apply automatic formatting to more test runner code, these were previously not done.

  • Avoid using shutil.copytree which fails to work when directory already exists, instead provide nuitka.util.FileOperations.copyTree and use that exclusively.


  • Added new mode of operation to test runners, only that executes just one test and stops, useful during development.

  • Added new mechanism for standalone tests to expression modules that need to be importable, or else to skip the test by a special comment in the file, instead of by coded checks in the test runner.

  • Added also for more complex cases, another form of special comment, that can be any expression, that decides if the test makes sense.

  • Cover also setuptools in our distutils tests and made the execution more robust against variable behavior of distutils and setuptools.

  • Added standalone test for Urllib3.

  • Added standalone test for rsa.

  • Added standalone test for Pmw.

  • Added standalone test for passlib.


Again this release is a sign of increasing adoption of Nuitka. The GSoC 2019 is also showing effects, definitely will in the next release.

This release has a lot of new optimization, called specialization, but for it to really used, in many instances, we need to get away from working on C types for variables only, and get to them beig used for expressions more often. Otherwise much of the new special code is not used for most code.

The focus of this release has been again to open up development further and to incorporate findings from users. The number of fixes or new use cases working is astounding.

In upcoming releases, new built-ins will be optimized, and specialization of operations will hit more and more code now that the infrastructure for it is in place.

Nuitka Release 0.6.3

This has a focus on organisational improvements. With more and more people joining Nuitka, normal developers as well as many GSoC 2019 students, the main focus was to open up the development tools and processes, and to improve documentation.

That said, an impressive amount of bug fixes was contributed, but optimization was on hold.

Bug Fixes

  • Windows: Added support for running compiled binaries in unicode path names.

  • Standalone: Added support for crytodomex and pycparser packages.

  • Standalone: Added support for OpenSSL support in PyQt on Windows.

  • Standalone: Added support for OpenGL support with QML in PyQt on Windows.

  • Standalone: Added support for SciPy and extended the NumPy plugin to also handle it.

  • UI: The option --plugin-list still needed a positional argument to work.

  • Make sure sys.base_prefix is set correctly too.

  • Python3: Also make sure sys.exec_prefix and sys.base_exec_prefix are set correctly.

  • Standalone: Added platform plugins for PyQt to the default list of sensible plugins to include.

  • Fix detection of standard library paths that include .. path elements.


  • Avoid using static C++ runtime library when using MinGW64.

New Features

  • Plugins: A plugin may now also generate data files on the fly for a given module.

  • Added support for FreeBSD/PowerPC arch which still uses gcc and not clang.


  • Nuitka is participating in the GSoC 2019.

  • Added documentation on how to create or use Nuitka plugins.

  • Added more API doc to functions that were missing them as part of the ongoing effort to complete it.

  • Updated to latest PyLint 2.3.1 for checking the code.

  • Scons: Using newer Scons inline copy with Python 2.7 as, the old one remains only used with Python 2.6, making it easier to know the relevant code.

  • Auto-format was very much enhanced and handles C and ReST files too now. For Python code it does pylint comment formatting, import statement sorting, and blackening.

  • Added script misc/ that adds a commit hook that runs auto-format on commit. Currently it commits unstaged content and therefore is not yet ready for prime time.

  • Moved adapted CPython test suites to GitHub repository under Nuitka Organisation.

  • Moved Nuitka-website repository to GitHub repository under Nuitka Organisation.

  • Moved Nuitka-speedcenter repository to GitHub repository under Nuitka Organisation.

  • There is now a Gitter chat for Nuitka community.

  • Many typo and spelling corrections on all the documentation.

  • Added short installation guide for Nuitka on Windows.


  • Moved commandline parsing helper functions from common code helpers to the main program where of course their only usage is.

  • Moved post processing of the created standalone binary from main control to the freezer code.

  • Avoid using chmod binary to remove executable bit from created extension modules.

  • Windows: Avoid using rt.exe and mt.exe to deal with copying the manifest from the python.exe to created binaries. Instead use new code that extracts and adds Windows resources.

  • Fixed many ResourceWarnings on Python3 by improved ways of handling files.

  • Fixed deprecation warnings related to not using

  • The runners in bin directory are now formatted with black too.


  • Detect Windows permission errors for two step execution of Nuitka as well, leading to retries should they occur.

  • The salt value for CPython cached results was improved to take more things into account.

  • Tests: Added more trick assignments and generally added more tests that were so far missing.


With the many organisational changes in place, my normal work is expected to resume for after and yield quicker improvements now.

It is also important that people are now enabled to contribute to the Nuitka web site and the Nuitka speedcenter. Hope is to see more improvements on this otherwise neglected areas.

And generally, it’s great to see that a community of people is now looking at this release in excitement and pride. Thanks to everybody who contributed!

Nuitka Release 0.6.2

This release has a huge focus on organisational things. Nuitka is growing in terms of contributors and supported platforms.

Bug Fixes

  • Fix, the Python flag --python-flag=-O was removing doc strings, but that should only be done with --python-flag=-OO which was added too.

  • Fix, accelerated binaries failed to load packages from the virtualenv (not venv) that they were created and ran with, due to not propagating sys.prefix.

  • Standalone: Do not include plat-* directories as frozen code, and also on some platforms they can also contain code that fails to import without error.

  • Standalone: Added missing implicit dependency needed for newer NumPy versions.

New Features

  • Added support for Alpine Linux.

  • Added support for MSYS2 based Python on Windows.

  • Added support for Python flag --python flag=-OO, which allows to remove doc strings.

  • Added experimental support for pefile based dependency scans on Windows, thanks to Orsiris for this contribution.

  • Added plugin for proper Tkinter standalone support on Windows, thanks to Jorj for this contribution.

  • There is now a __compiled__ attribute for each module that Nuitka has compiled. Should be like this now, and contains Nuitka version information for you to use, similar to what sys.version_info gives as a namedtuple for your checks.

    __nuitka_version__(major=0, minor=6, micro=2, releaselevel="release")


  • Experimental code for variant types for int and long values, that can be plain C value, as well as the PyObject *. This is not yet completed though.

  • Minor refinements of specialized code variants reducing them more often the actual needed code.


  • The Nuitka GitHub Organisation that was created a while ago and owns the Nuitka repo now, has gained members. Check out for their list. This is an exciting transformation for Nuitka.

  • Nuitka is participating in the GSoC 2019 under the PSF umbrella. We hope to grow even further. Thanks to the mentors who volunteered for this important task. Check out the GSoC 2019 page and thanks to the students that are already helping out.

  • Added Nuitka internal API documentation that will receive more love in the future. It got some for this release, but a lot is missing.

  • The Nuitka code has been black-ened and is formatted with an automatic tool now all the way, which makes contributors lives easier.

  • Added documentation for questions received as part of the GSoC applications and ideas work.

  • Some proof reading pull requests were merged for the documentation, thanks to everybody who addresses these kinds of errors. Sometimes typos, sometimes broken links, etc.

  • Updated inline copy of Scons used for Python3 to 3.0.4, which hopefully means more bugs are fixed.


This release is a sign of increasing adoption of Nuitka. The GSoC 2019 is showing early effects, as is more developers joining the effort. These are great times for Nuitka.

This release has not much on the optimization side that is user visible, but the work that has begun is capable of producing glorious benchmarks once it will be finished.

The focus on this and coming releases is definitely to open up the Nuitka development now that people are coming in as permanent or temporary contributors in (relatively) high numbers.

Nuitka Release 0.6.1

This release comes after a relatively long time, and contains important new optimization work, and even more bug fixes.

Bug Fixes

  • Fix, the options --[no]follow-import-to=package_name was supposed to not follow into the given package, but the check was executed too broadly, so that e.g. package_name2 was also affected. Fixed in already.

  • Fix, wasn’t detecting multiple recursions into the same package in module mode, when attempting to compile a whole sub-package. Fixed in already.

  • Fix, constant values are used as C boolean values still for some of the cases. Fixed in already.

  • Fix, referencing a function cannot raise an exception, but that was not annotated. Fixed in already.

  • macOS: Use standard include of C bool type instead of rolling our own, which was not compatible with newest Clang. Fixed in already.

  • Python3: Fix, the bytes built-in type actually does have a __float__ slot. Fixed in already.

  • Python3.7: Types that are also sequences still need to call the method __class_getitem__ for consideration. Fixed in already.

  • Python3.7: Error exits from program exit could get lost on Windows due to __spec__ handling not preserving errors. Fixed in already.

  • Windows: Negative exit codes from Nuitka, e.g. due to a triggered assertion in debug mode were not working. Fixed in already.

  • Fix, conditional and expressions were mis-optimized when not used to not execute the right hand side still. Fixed in already.

  • Python3.6: Fix, generators, coroutines, and asyncgen were not properly supporting annotations for local variables. Fixed in already.

  • Python3.7: Fix, class declarations had memory leaks that were untestable before 3.7.1 fixed reference count issues in CPython. Fixed in already.

  • Python3.7: Fix, asyncgen expressions can be created in normal functions without an immediate awaiting of the iterator. This new feature was not correctly supported.

  • Fix, star imports on the module level should disable built-in name optimization except for the most critical ones, otherwise e.g. names like all or pow can become wrong. Previous workarounds for pow were not good enough.

  • Fix, the scons for Python3 failed to properly report build errors due to a regression of the Scons version used for it. This would mask build errors on Windows.

  • Python3.4: Fix, packages didn’t indicate that they are packages in their __spec__ value, causing issues with importlib_resources module.

  • Python3.4: The __spec__ values of compiled modules didn’t have compatible origin and has_location values preventing importlib_resources module from working to load data files.

  • Fix, packages created from .pth files were also considered when checking for sub-packages of a module.

  • Standalone: Handle cases of conflicting DLLs better. On Windows pick the newest file version if different, and otherwise just report and pick randomly because we cannot really decide which ought to be loaded.

  • Standalone: Warn about collisions of DLLs on non-Windows only as this can happen with wheels apparently.

  • Standalone: For Windows Python extension modules .pyd files, remove the SxS configuration for cases where it causes problems, not needed.

  • Fix: The exec statement on file handles was not using the proper filename when compiling, therefore breaking e.g. inspect.getsource on functions defined there.

  • Standalone: Added support for OpenGL platform plugins to be included automatically.

  • Standalone: Added missing implicit dependency for zmq module.

  • Python3.7: Fix, using the -X utf8 flag on the calling interpreter, aka --python-flag=utf8_mode was not preserved in the compiled binary in all cases.


  • Enabled C target type void which will catch creating unused stuff more immediately and give better code for expression only statements.

  • Enabled in-place optimization for module variables, avoiding write back to the module dict for unchanged values, accelerating these operations.

  • Compile time memory savings for the yield node of Python2, no need to track if it is in an exception handler, not relevant there.

  • Using the single child node for the yield nodes gives memory savings at compile time for these, while also making them operate faster.

  • More kinds of in-place operations are now optimized, e.g. int += int and the bytes ones were specialized to perform real in-place extension where possible.

  • Loop variables no longer loose type information, but instead collect the set of possible type shapes allowing optimization for them.


  • Corrected download link for Arch AUR link of develop package.

  • Added repository for Ubuntu Cosmic (18.10) for download.

  • Added repository for Fedora 29 for download.

  • Describe the exact format used for clang-format in the Developer Manual.

  • Added description how to use CondaCC on Windows to the User Manual.


  • The operations used for async for, async with, and await were all doing a look-up of an awaitable, and then executing the yield from that awaitable as one thing. Now this is split into two parts, with a new ExpressionYieldFromAwaitable as a dedicated node.

  • The yield node types, now 3 share a base class and common computation for now, enhancing the one for awaitiable, which was not fully annotating everything that can happen.

  • In code generation avoid statement blocks that are not needed, because there are no local C variables declared, and properly indent them.


  • Fixups for the manual Valgrind runner and the UI changes.

  • Test runner detects lock issue of clcache on Windows and considers it a permission problem that causes a retry.


This addresses even more corner cases not working correctly, the out of the box experience should be even better now.

The push towards C level performance for integer operation was held up by the realization that loop SSA was not yet there really, and that it had to be implemented, which of course now makes a huge difference for the cases where e.g. bool are being used. There is no C type for int used yet, which limits the impact of optimization to only taking shortcuts for the supported types. These are useful and faster of course, but only building blocks for what is to come.

Most of the effort went into specialized helpers that e.g. add a float and and int value in a dedicated fashion, as well as comparison operations, so we can fully operate some minimal examples with specialized code. This is too limited still, and must be applied to ever more operations.

What’s more is that the benchmarking situation has not improved. Work will be needed in this domain to make improvements more demonstrable. It may well end up being the focus for the next release to improve Nuitka speedcenter to give more fine grained insights across minor changes of Nuitka and graphs with more history.

Nuitka Release 0.6.0

This release adds massive improvements for optimization and a couple of bug fixes.

It also indicates reaching the mile stone of doing actual type inference, even if only very limited.

And with the new version numbers, lots of UI changes go along. The options to control recursion into modules have all been renamed, some now have different defaults, and finally the filenames output have changed.

Bug Fixes

  • Python3.5: Fix, the awaiting flag was not removed for exceptions thrown into a coroutine, so next time it appeared to be awaiting instead of finished.

  • Python3: Classes in generators that were using built-in functions crashed the compilation with C errors.

  • Some regressions for XML outputs from previous changes were fixed.

  • Fix, hasattr was not raising an exception if used with non-string attributes.

  • For really large compilations, MSVC linker could choke on the input file, line length limits, which is now fixed for the inline copy of Scons.

  • Standalone: Follow changed hidden dependency of PyQt5 to PyQt5.sip for newer versions

  • Standalone: Include certificate file using by requests module in some cases as a data file.


  • Enabled C target type nuitka_bool for variables that are stored with boolean shape only, and generate C code for those

  • Using C target type nuitka_bool many more expressions are now handled better in conditions.

  • Enhanced is and is not to be C source type aware, so they can be much faster for them.

  • Use C target type for bool built-in giving more efficient code for some source values.

  • Annotate the not result to have boolean type shape, allowing for more compile time optimization with it.

  • Restored previously lost optimization of loop break handling StopIteration which makes loops much faster again.

  • Restore lost optimization of subscripts with constant integer values making them faster again.

  • Optimize in-place operations for cases where left, right, or both sides have known type shapes for some values. Initially only a few variants were added, but there is more to come.

  • When adjacent parts of an f-string become known string constants, join them at compile time.

  • When there is only one remaining part in an f-string, use that directly as the result.

  • Optimize empty f-strings directly into empty strings constant during the tree building phase.

  • Added specialized attribute check for use in re-formulations that doesn’t expose exceptions.

  • Remove locals sync operation in scopes without local variables, e.g. classes or modules, making exec and the like slightly leaner there.

  • Remove try nodes that did only re-raise exceptions.

  • The del of variables is now driven fully by C types and generates more compatible code.

  • Removed useless double exception exits annotated for expressions of conditions and added code that allows conditions to adapt themselves to the target shape bool during optimization.

New Features

  • Added support for using .egg files in PYTHONPATH, one of the more rare uses, where Nuitka wasn’t yet compatible.

  • Output binaries in standalone mode with platform suffix, on non-Windows that means no suffix. In accelerated mode on non-Windows, use .bin as a suffix to avoid collision with files that have no suffix.

  • Windows: It’s now possible to use clang-cl.exe for CC with Nuitka as a third compiler on Windows, but it requires an existing MSVC install to be used for resource compilation and linking.

  • Windows: Added support for using ccache.exe and clcache.exe, so that object files can now be cached for re-compilation.

  • For debug mode, report missing in-place helpers. These kinds of reports are to become more universal and are aimed at recognizing missed optimization chances in Nuitka. This features is still in its infancy. Subsequent releases will add more like these.


  • Disabled comments on the web site, we are going to use Twitter instead, once the site is migrated to an updated Nikola.

  • The static C code is now formatted with clang-format to make it easier for contributors to understand.

  • Moved the construct runner to top level binary and use it from there, with future changes coming that should make it generally useful outside of Nuitka.

  • Enhanced the issue template to tell people how to get the develop version of Nuitka to try it out.

  • Added documentation for how use the object caching on Windows to the User Manual.

  • Removed the included GUI, originally intended for debugging, but XML outputs are more powerful anyway, and it had been in disrepair for a long time.

  • Removed long deprecated options, e.g. --exe which has long been the default and is no more accepted.

  • Renamed options to include plugin files to --include-plugin-directory and --include-plugin-files for more clarity.

  • Renamed options for recursion control to e.g. --follow-imports to better express what they actually do.

  • Removed --python-version support for switching the version during compilation. This has only worked for very specific circumstances and has been deprecated for a while.

  • Removed --code-gen-no-statement-lines support for not having line numbers updated at run time. This has long been hidden and probably would never gain all that much, while causing a lot of incompatibilty.


  • Moved command line arguments to dedicated module, adding checks was becoming too difficult.

  • Moved rich comparison helpers to a dedicated C file.

  • Dedicated binary and unary node bases for clearer distinction and more efficient memory usage of unuary nodes. Unary operations also no longer have in-place operation as an issue.

  • Major cleanup of variable accesses, split up into multiple phases and all including module variables being performed through C types, with no special cases anymore.

  • Partial cleanups of C type classes with code duplications, there is much more to resolve though.

  • Windows: The way exec was performed is discouraged in the subprocess documentation, so use a variant that cannot block instead.

  • Code proving information about built-in names and values was using not very portable constructs, and is now written in a way that PyPy would also like.


  • Avoid using 2to3 for basic operators test, removing test of some Python2 only stuff, that is covered elsewhere.

  • Added ability to cache output of CPython when comparing to it. This is to allow CI tests to not execute the same code over and over, just to get the same value to compare with. This is not enabled yet.


This release marks a point, from which on performance improvements are likely in every coming release. The C target types are a major milestone. More C target types are in the work, e.g. void is coming for expressions that are done, but not used, that is scheduled for the next release.

Although there will be a need to also adapt optimization to take full advantage of it, progress should be quick from here. There is a lot of ground to cover, with more C types to come, and all of them needing specialized helpers. But as soon as e.g. int, str are covered, many more programs are going to benefiting from this.

Nuitka Release 0.5.33

This release contains a bunch of fixes, most of which were previously released as part of hotfixes, and important new optimization for generators.

Bug Fixes

  • Fix, nested functions with local classes using outside function closure variables were not registering their usage, which could lead to errors at C compile time. Fixed in already.

  • Fix, usage of built-in calls in a class level could crash the compiler if a class variable was updated with its result. Fixed in already.

  • Python 3.7: The handling of non-type bases classes was not fully compatible and wrong usages were giving AttributeError instead of TypeError. Fixed in already.

  • Python 3.5: Fix, await expressions didn’t annotate their exception exit. Fixed in already.

  • Python3: The enum module usages with __new__ in derived classes were not working, due to our automatic staticmethod decoration. Turns out, that was only needed for Python2 and can be removed, making enum work all the way. Fixed in already.

  • Fix, recursion into __main__ was done and could lead to compiler crashes if the main module was named like that. This is not prevented. Fixed in already.

  • Python3: The name for list contraction’s frames was wrong all along and not just changed for 3.7, so drop that version check on it. Fixed in already.

  • Fix, the hashing of code objects has creating a key that could produce more overlaps for the hash than necessary. Using a C1 on line 29 and C on line 129, was considered the same. And that is what actually happened. Fixed in already.

  • macOS: Various fixes for newer Xcode versions to work as well. Fixed in already.

  • Python3: Fix, the default __annotations__ was the empty dict and could be modified, leading to severe corruption potentially. Fixed in already.

  • Python3: When an exception is thrown into a generator that currently does a yield from is not to be normalized.

  • Python3: Some exception handling cases of yield from were leaking references to objects. Fixed in already.

  • Python3: Nested namespace packages were not working unless the directory continued to exist on disk. Fixed in already.

  • Standalone: Do not include icuuc.dll which is a system DLL. Fixed in already.

  • Standalone: Added hidden dependency of newer version of sip. Fixed in already.

  • Standalone: Do not copy file permissions of DLLs and extension modules as that makes deleting and modifying them only harder. Fixed in already.

  • Windows: The multiprocessing plugin was not always properly patching the run time for all module loads, made it more robust. Fixed in already.

  • Standalone: Do not preserve permissions of copied DLLs, which can cause issues with read-only files on Windows when later trying to overwrite or remove files.

  • Python3.4: Make sure to disconnect finished generators from their frames to avoid potential data corruption. Fixed in already.

  • Python3.5: Make sure to disconnect finished coroutines from their frames to avoid potential data corruption. Fixed in already.

  • Python3.6: Make sure to disconnect finished asyncgen from their frames to avoid potential data corruption. Fixed in already.

  • Python3.5: Explicit frame closes of frames owned by coroutines could corrupt data. Fixed in already.

  • Python3.6: Explicit frame closes of frames owned by asyncgen could corrupt data. Fixed in already.

  • Python 3.4: Fix threaded imports by properly handling _initializing in compiled modules __spec__ attributes. Before it happen that another thread attempts to use an unfinished module. Fixed in already.

  • Fix, the options --include-module and --include-package were present but not visible in the help output. Fixed in already.

  • Windows: The multiprocessing plugin failed to properly pass compiled functions. Fixed in already.

  • Python3: Fix, optimization for in-place operations on mapping values are not allowed and had to be disabled. Fixed in already.

  • Python 3.5: Fixed exception handling with coroutines and asyncgen throw to not corrupt exception objects.

  • Python 3.7: Added more checks to class creations that were missing for full compatibility.

  • Python3: Smarter hashing of unicode values avoids increased memory usage from cached converted forms in debug mode.


  • The issue tracker on GitHub is now the one that should be used with Nuitka, winning due to easier issue templating and integration with pull requests.

  • Document the threading model and exception model to use for MinGW64.

  • Removed the enum plug-in which is no longer useful after the improvements to the staticmethod handling for Python3.

  • Added Python 3.7 testing for Travis.

  • Make it clear in the documentation that pyenv is not supported.

  • The version output includes more information now, OS and architecture, so issue reports should contain that now.

  • On PyPI we didn’t yet indicated Python 3.7 as supported, which it of course is.

New Features

  • Added support for MiniConda Python.


  • Using goto based generators that return from execution and resume based on heap storage. This makes tests using generators twice as fast and they no longer use a full C stack of 2MB, but only 1K instead.

  • Conditional a if cond else b, a and b, a or b expressions of which the result value is are now transformed into conditional statements allowing to apply further optimizations to the right and left side expressions as well.

  • Replace unused function creations with side effects from their default values with just those, removing more unused code.

  • Put all statement related code and declarations for it in a dedicated C block, making things slightly more easy for the C compiler to reuse the stack space.

  • Avoid linking against libpython in module mode on everything but Windows where it is really needed. No longer check for static Python, not needed anymore.

  • More compact function, generator, and asyncgen creation code for the normal cases, avoid qualname if identical to name for all of them.

  • Python2 class dictionaries are now indeed directly optimized, giving more compact code.

  • Module exception exits and thus its frames have become optional allowing to avoid some code for some special modules.

  • Uncompiled generator integration was backported to 3.4 as well, improving compatibility and speed there as well.


  • Frame object and their cache declarations are now handled by the way of allocated variable descriptions, avoid special handling for them.

  • The interface to “forget” a temporary variable has been replaced with a new method that skips a number for it. This is done to keep expression use the same indexes for all their child expressions, but this is more explicit.

  • Instead of passing around C variables names for temporary values, we now have full descriptions, with C type, code name, storage location, and the init value to use. This makes the information more immediately available where it is needed.

  • Variable declarations are now created when needed and stored in dedicated variable storage objects, which then in can generate the code as necessary.

  • Module code generation has been enhanced to be closer to the pattern used by functions, generators, etc.

  • There is now only one spot that creates variable declaration, instead of previous code duplications.

  • Code objects are now attached to functions, generators, coroutines, and asyncgen bodies, and not anymore to the creation of these objects. This allows for simpler code generation.

  • Removed fiber implementations, no more needed.


  • Finally the asyncgen tests can be enabled in the CPython 3.6 test suite as the corrupting crash has been identified.

  • Cover ever more cases of spurious permission problems on Windows.

  • Added the ability to specify specific modules a comparison test should recurse to, making some CPython tests follow into modules where actual test code lives.


This release is huge in many ways.

First, finishing “goto generators” clears an old scalability problem of Nuitka that needed to be addressed. No more do generators/coroutines/asyncgen consume too much memory, but instead they become as lightweight as they ought to be.

Second, the use of variable declarations carying type information all through the code generation, is an important pre-condition for “C types” work to resume and become possible, what will be 0.6.0 and the next release.

Third, the improved generator performance will be removing a lot of cases, where Nuitka wasn’t as fast, as its current state not using “C types” yet, should allow. It is now consistently faster than CPython for everything related to generators.

Fourth, the fibers were a burden for the debugging and linking of Nuitka on various platforms, as they provided deprecated interfaces or not. As they are now gone, Nuitka ought to definitely work on any platform where Python works.

From here on, C types work can take it, and produce the results we are waiting for in the next major release cycle that is about to start.

Also the amount of fixes for this release has been incredibly high. Lots of old bugs esp. for coroutines and asyncgen have been fixed, this is not only faster, but way more correct. Mainly due to the easier debugging and interface to the context code, bugs were far easier to avoid and/or find.

Nuitka Release 0.5.32

This release contains substantial new optimization, bug fixes, and already the full support for Python 3.7. Among the fixes, the enhanced coroutine work for compatibility with uncompiled ones is most important.

Bug Fixes

  • Fix, was optimizing write backs of attribute in-place assignments falsely.

  • Fix, generator stop future was not properly supported. It is now the default for Python 3.7 which showed some of the flaws.

  • Python3.5: The __qualname__ of coroutines and asyncgen was wrong.

  • Python3.5: Fix, for dictionary unpackings to calls, check the keys if they are string values, and raise an exception if not.

  • Python3.6: Fix, need to check assignment unpacking for too short sequences, we were giving IndexError instead of ValueError for these. Also the error messages need to consider if they should refer to “at least” in their wording.

  • Fix, outline nodes were cloned more than necessary, which would corrupt the code generation if they later got removed, leading to a crash.

  • Python3.5: Compiled coroutines awaiting uncompiled coroutines was not working properly for finishing the uncompiled ones. Also the other way around was raising a RuntimeError when trying to pass an exception to them when they were already finished. This should resolve issues with asyncio module.

  • Fix, side effects of a detected exception raise, when they had an exception detected inside of them, lead to an infinite loop in optimization. They are now optimized in-place, avoiding an extra step later on.

New Features

  • Support for Python 3.7 with only some corner cases not supported yet.


  • Delay creation of StopIteration exception in generator code for as long as possible. This gives more compact code for generations, which now pass the return values via compiled generator attribute for Python 3.3 or higher.

  • Python3: More immediate re-formulation of classes with no bases. Avoids noise during optimization.

  • Python2: For class dictionaries that are only assigned from values without side effects, they are not converted to temporary variable usages, allowing the normal SSA based optimization to work on them. This leads to constant values for class dictionaries of simple classes.

  • Explicit cleanup of nodes, variables, and local scopes that become unused, has been added, allowing for breaking of cyclic dependencies that prevented memory release.


  • Adapted 3.5 tests to work with 3.7 coroutine changes.

  • Added CPython 3.7 test suite.


  • Removed remaining code that was there for 3.2 support. All uses of version comparisons with 3.2 have been adapted. For us, Python3 now means 3.3, and we will not work with 3.2 at all. This removed a fair bit of complexity for some things, but not all that much.

  • Have dedicated file for import released helpers, so they are easier to find if necessary. Also do not have code for importing a name in the header file anymore, not performance relevant.

  • Disable Python warnings when running scons. These are particularly given when using a Python debug binary, which is happening when Nuitka is run with --python-debug option and the inline copy of Scons is used.

  • Have a factory function for all conditional statement nodes created. This solved a TODO and handles the creation of statement sequences for the branches as necessary.

  • Split class reformulation into two files, one for Python2 and one for Python3 variant. They share no code really, and are too confusing in a single file, for the huge code bodies.

  • Locals scopes now have a registry, where functions and classes register their locals type, and then it is created from that.

  • Have a dedicated helper function for single argument calls in static code that does not require an array of objects as an argument.


  • There are now requirements-devel.txt and requirements.txt files aimed at usage with scons and by users, but they are not used in installation.


This releases has this important step to add conversion of locals dictionary usages to temporary variables. It is not yet done everywhere it is possible, and the resulting temporary variables are not yet propagated in the all the cases, where it clearly is possible. Upcoming releases ought to achieve that most Python2 classes will become to use a direct dictionary creation.

Adding support for Python 3.7 is of course also a huge step. And also this happened fairly quickly and soon after its release. The generic classes it adds were the only real major new feature. It breaking the internals for exception handling was what was holding back initially, but past that, it was really easy.

Expect more optimization to come in the next releases, aiming at both the ability to predict Python3 metaclasses __prepare__ results, and at more optimization applied to variables after they became temporary variables.

Nuitka Release 0.5.31

This release is massive in terms of fixes, but also adds a lot of refinement to code generation, and more importantly adds experimental support for Python 3.7, while enhancing support for Pyt5 in standalone mode by a lot.

Bug Fixes

  • Standalone: Added missing dependencies for PyQt5.Qt module.

  • Plugins: Added support for PyQt5.Qt module and its qml plugins.

  • Plugins: The sensible plugin list for PyQt now includes that platforms plugins on Windows too, as they are kind of mandatory.

  • Python3: Fix, for uninstalled Python versions wheels that linked against the Python3 library as opposed to Python3X, it was not found.

  • Standalone: Prefer DLLs used by main program binary over ones used by wheels.

  • Standalone: For DLLs added by Nuitka plugins, add the package directory to the search path for dependencies where they might live.

  • Fix, the vars built-in didn’t annotate its exception exit.

  • Python3: Fix, the bytes and complex built-ins needs to be treated as a slot too.

  • Fix, consider if del variable must be assigned, in which case no exception exit should be created. This prevented Tkinter compilation.

  • Python3.6: Added support for the following language construct:

    d = {"metaclass": M}
    class C(**d):
  • Python3.5: Added support for cyclic imports. Now a from import with a name can really cause an import to happen, not just a module attribute lookup.

  • Fix, hasattr was never raising exceptions.

  • Fix, bytearray constant values were considered to be non-iterable.

  • Python3.6: Fix, now it is possible to del __annotations__ in a class and behave compatible. Previously in this case we were falling back to the module variable for annotations used after that which is wrong.

  • Fix, some built-in type conversions are allowed to return derived types, but Nuitka assumed the exact type, this affected bytes, int, long, unicode.

  • Standalone: Fix, the _socket module was insisted on to be found, but can be compiled in.

New Features

  • Added experimental support for Python 3.7, more work will be needed though for full support. Basic tests are working, but there are are at least more coroutine changes to follow.

  • Added support for building extension modules against statically linked Python. This aims at supporting manylinux containers, which are supposed to be used for creating widely usable binary wheels for Linux. Programs won’t work with statically linked Python though.

  • Added options to allow ignoring the Windows cache for DLL dependencies or force an update.

  • Allow passing options from distutils to Nuitka compilation via setup options.

  • Added option to disable the DLL dependency cache on Windows as it may become wrong after installing new software.

  • Added experimental ability to provide extra options for Nuitka to setuptools.

  • Python3: Remove frame preservation and restoration of exceptions. This is not needed, but leaked over from Python2 code.


  • Apply value tracing to local dict variables too, enhancing the optimization for class bodies and function with exec statements by a lot.

  • Better optimization for “must not have value”, wasn’t considering merge traces of uninitialized values, for which this is also the case.

  • Use 10% less memory at compile time due to specialized base classes for statements with a single child only allowing __slots__ usage by not having multiple inheritance for those.

  • More immediately optimize branches with known truth values, so that merges are avoided and do not prevent trace based optimization before the pass after the next one. In some cases, optimization based on traces could fail to be done if there was no next pass caused by other things.

  • Much faster handling for functions with a lot of eval and exec calls.

  • Static optimization of type with known type shapes, the value is predicted at compile time.

  • Optimize containers for all compile time constants into constant nodes. This also enables further compile time checks using them, e.g. with isinstance or in checks.

  • Standalone: Using threads when determining DLL dependencies. This will speed up the un-cached case on Windows by a fair bit.

  • Also remove unused assignments for mutable constant values.

  • Python3: Also optimize calls to bytes built-in, this was so far not done.

  • Statically optimize iteration over constant values that are not iterable into errors.

  • Removed Fortran, Java, LaTex, PDF, etc. stuff from the inline copies of Scons for faster startup and leaner code. Also updated to 3.0.1 which is no important difference over 3.0.0 for Nuitka however.

  • Make sure to always release temporary objects before checking for error exits. When done the other way around, more C code than necessary will be created, releasing them in both normal case and error case after the check.

  • Also remove unused assignments in case the value is a mutable constant.


  • Don’t store “version” numbers of variable traces for code generation, instead directly use the references to the value traces instead, avoiding later lookups.

  • Added dedicated module for complex built-in nodes.

  • Moved C helpers for integer and complex types to dedicated files, solving the TODOs around them.

  • Removed some Python 3.2 only codes.


  • For better bug reports, the --version output now contains also the Python version information and the binary path being used.

  • Started using specialized exceptions for some types of errors, which will output the involved data for better debugging without having to reproduce anything. This does e.g. output XML dumps of problematic nodes.

  • When encountering a problem (compiler crash) in optimization, output the source code line that is causing the issue.

  • Added support for Fedora 28 RPM builds.

  • Remove more instances of mentions of 3.2 as supported or usable.

  • Renovated the graphing code and made it more useful.


This release marks important progress, as the locals dictionary tracing is a huge step ahead in terms of correctness and proper optimization. The actual resulting dictionary is not yet optimized, but that ought to follow soon now.

The initial support of 3.7 is important. Right now it apparently works pretty well as a 3.6 replacement already, but definitely a lot more work will be needed to fully catch up.

For standalone, this accumulated a lot of improvements related to the plugin side of Nuitka. Thanks to those involved in making this better. On Windows things ought to be much faster now, due to parallel usage of dependency walker.

Nuitka Release 0.5.30

This release has improvements in all areas. Many bug fixes are accompanied with optimization changes towards value tracing.

Bug Fixes

  • Fix, the new setuptools runners were not used by pip breaking the use of Nuitka from PyPI.

  • Fix, imports of six.moves could crash the compiler for built-in names. Fixed in already.

  • Windows: Make the nuitka-run not a symlink as these work really bad on that platform, instead make it a full copy just like we did for nuitka3-run already. Fixed in already.

  • Python3.5: In module mode, types.coroutine was monkey patched into an endless recursion if including more than one module, e.g. for a package. Fixed in already.

  • Python3.5: Dictionary unpackings with both star arguments and non star arguments could leak memory. Fixed in already.

    c = {a: 1, **d}
  • Fix, distutils usage was not working for Python2 anymore, due to using super for what are old style classes on that version.

  • Fix, some method calls to C function members could leak references.

    class C:
        for_call = functools.partial
        def m(self):
            self.for_call()  # This leaked a reference to the descriptor.
  • Python3.5: The bases classes should be treated as an unpacking too.

    class C(*D):  # Allowed syntax that was not supported.
  • Windows: Added back batch files to run Nuitka from the command line. Fixed in already.

New Features

  • Added option --include-package to force inclusion of a whole package with the submodules in a compilation result.

  • Added options --include-module to force inclusion of a single module in a compilation result.

  • The multiprocessing plug-in got adapted to Python 3.4 changes and will now also work in accelerated mode on Windows.

  • It is now possible to specify the Qt plugin directories with e.g. --enable-plugin-=qt_plugins=imageformats and have only those included. This should avoid dependency creep for shared libraries.

  • Plugins can now make the decision about recursing to a module or not.

  • Plugins now can get their own options passed.


  • The re-raising of exceptions has gotten its own special node type. This aims at more readability (XML output) and avoiding the overhead of checking potential attributes during optimization.

  • Changed built-in int, long, and float to using a slot mechanism that also analyses the type shape and detects and warns about errors at compile time.

  • Changed the variable tracing to value tracing. This meant to cleanup all the places that were using it to find the variable.

  • Enable must have / must not value value optimization for all kinds of variables including module and closure variables. This often avoids error exits and leads to smaller and faster generated code.


  • Added burn test with local install of pip distribution to virtualenv before making any PyPI upload. It seems pip got its specific error sources too.

  • Avoid calling 2to3 and prefer <python> -m lib2to3 instead, as it seems at least Debian Testing stopped to provide the binary by default. For Python 2.6 and 3.2 we continue to rely on it, as the don’t support that mode of operation.

  • The PyLint checks have been made more robust and even more Python3 portable.

  • Added PyLint to Travis builds, so PRs are automatically checked too.

  • Added test for distutils usage with Nuitka that should prevent regressions for this new feature and to document how it can be used.

  • Make coverage taking work on Windows and provide the full information needed, the rendering stage is not there working yet though.

  • Expanded the trick assignment test cases to cover more slots to find bugs introduced with more aggressive optimization of closure variables.

  • New test to cover multiprocessing usage.

  • Generating more code tests out of doctests for increased coverage of Nuitka.


  • Stop using --python-version in tests where they still remained.

  • Split the forms of int and long into two different nodes, they share nothing except the name. Create the constants for the zero arg variant more immediately.

  • Split the output comparison part into a dedicated testing module so it can be re-used, e.g. when doing distutils tests.

  • Removed dead code from variable closure taking.

  • Have a dedicated module for the metaclass of nodes in the tree, so it is easier to find, and doesn’t clutter the node base classes module as much.

  • Have a dedicated node for reraise statements instead of checking for all the arguments to be non-present.


  • There is now a pull request template for GitHub when used.

  • Deprecating the --python-version argument which should be replaced by using -m nuitka with the correct Python version. Outputs have been updated to recommend this one instead.

  • Make automatic import sorting and auto-format tools properly executable on Windows without them changing new lines.

  • The documentation was updated to prefer the call method with -m nuitka and manually providing the Python binary to use.


This release continued the distutils integration adding first tests, but more features and documentation will be needed.

Also, for the locals dictionary work, the variable tracing was made generic, but not yet put to use. If we use this to also trace dictionary keys, we can expect a lot of improvements for class code again.

The locals dictionary tracing will be the focus before resuming the work on C types, where the ultimate performance boost lies. However, currently, not the full compatibility has been achieved even with currently using dictionaries for classes, and we would like to be able to statically optimize those better anyway.

Nuitka Release 0.5.29

This release comes with a lot of improvements across the board. A lot of focus has been givevn to the packaging side of Nuitka, but also there is a lot of compatibility work.

Bug Fixes

  • Windows: When using Scons for Python3 and Scons for Python2 on the same build directory, a warning would be given about the need to migrate. Make the Scons cache directory use the Python ABI version as a key too, to avoid these issues. Fixed in already.

  • Windows: Fixup for Python3 and Scons no more generating the MinGW64 import library for Python anymore properly. Was only working if cached from a previous install of Nuitka. Fixed in already.

  • Plugins: Made the data files plugin mandatory and added support for the scrapy package needs.

  • Fix, added implicit dependencies for pkg_resources.external package. Fixed in already.

  • Fix, an import of x.y where this was not a package didn’t cause the package x to be included.

  • Standalone: Added support for six.moves and requests.packages meta imports, these cause hidden implicit imports, that are now properly handled.

  • Standalone: Patch the __file__ value for technical bytecode modules loaded during Python library initialization in a more compatible way.

  • Standalone: Extension modules when loaded might actually raise legit errors, e.g. ImportError of another module, don’t make those into SystemError anymore.

  • Python3.2: The __package__ of sub-packages was wrong, which could cause issues when doing relative imports in that sub-package.

  • Python3: Contractions in a finally clause could crash the compiler.

  • Fix, unused closure variables could lead to a crash in they were passed to a nested function.

  • Linux: Standalone dependency analysis could enter an endless recursion in case of cyclic dependencies.

  • Python3.6: Async generation expressions need to return a None value too.

  • Python3.4: Fix, __spec__ is a package attribute and not a built-in value.

New Features

  • It is now possible to run Nuitka with some_python_you_choose -m nuitka ... and therefore know exactly which Python installation is going to be used. It does of course need Nuitka installed for this to work. This mechanism is going to replace the --python-version mechanism in the future.

  • There are dedicated runners for Python3, simply use nuitka3 or nuitka3-run to execute Nuitka if your code is Python3 code.

  • Added warning for implicit exception raises due to mismatch in unpacking length. These are statically detected, but so far were not warned about.

  • Added cache for depends.exe results. This speeds up standalone mode again as some of these calls were really slow.

  • The import tracer is more robust against recursion and works with Python3 now.

  • Added an option to assume yes for downloading questions. The currently only enables the download of depends.exe and is intended for CI servers.

  • There is now a report file for scons, which records the values used to run things, this could be useful for debugging.

  • Nuitka now registers with distutils and can be used with bdist_wheel directly, but this lacks documentation and tests. Many improvements in the distutils build.


  • Forward propagate compile time constants even if they are only potential usages. This is actually the case where this makes the most sense, as it might remove its use entirely from the branches that do not use it.

  • Avoid extra copy of finally code. The cloning operation takes time and memory, and this shaved of 0.3% of Nuitka memory usage, as these can also become dangling.

  • Class dictionaries are now proper dictionaries in optimization, using some dedicated code for name lookups that are transformed to dedicated locals dictionary or mapping (Python3) accesses. This currently does not fully optimize, but will in coming releases, and saves about 25% of memory compared to the old code.

  • Treating module attributes __package__, __loader__, __file__, and __spec__ with dedicated nodes, that allow or forbid optimization dependent on usage.

  • Python3.6: Async generator expressions were not working fully, become more compatible.

  • Fix, using super inside a contraction could crash the compiler.

  • Fix, also accept __new__ as properly decorated in case it’s a classmethod too.

  • Fix, removed obsolete --nofreeze-stdlib which only complicated using the --recurse-stdlib which should be used instead.


  • The nuitka Python package is now installed into the public namespace and used from there. There are distinct copies to be installed for both Python2 and Python3 on platforms where it is supported.

  • Using twine for upload to PyPI now as recommended on their site.

  • Running pylint on Windows became practical again.

  • Added RPM packages for Fedora 26 and 27, these used to fail due to packaging issues.

  • Added RPM packages for openSUSE Leap 42.2, 42.3 and 15.0 which were simply missing.

  • Added RPM packages for SLE 15.

  • Added support for PyLint 1.8 and its new warnings.

  • The RPM packages no longer contain nuitka-run3, it will be replaced by the new nuitka3-run which is in all packages.

  • The runners used for installation are now easy install created, but patched to avoid overhead at run time.

  • Added repository for Ubuntu Artful (17.10) for download, removed support for Ubuntu Yakkety, Vivid and Zesty (no more supported by them).

  • Removed support for Debian Wheezy and Ubuntu Precise (they are too old for modern packaging used).

  • There is now a issue template for GitHub when used.


  • Windows: Standalone tests were referencing an old path to depends.exe that wasn’t populated on new installs.

  • Refinements for CPython test suites to become more stable in results. Some tests occasionally fail to clean up, or might do nondeterministic outputs, or are not relevant at all.

  • The tests don’t use the runners, but more often do -m nuitka to become executable without having to find the proper runner. This improves usage during the RPM builds and generally.

  • Travis: Do not test development versions of CPython, even for stable release, they break too often.


This release consolidates a lot of what we already had, adding hopeful stuff for distutils integration. This will need tests and documentation though, but should make Nuitka really easy to use. A few features are still missing to make it generally reliable in that mode, but they are going to come.

Also the locals dictionary work is kind of incomplete without a proper generic tracing of not only local variables, but also dictionary keys. With that work in place, a lot of improvements will happen.

Nuitka Release 0.5.28

This release has a focus on compatibility work and contains bug fixes and work to enhance the usability of Nuitka by integrating with distutils. The major improvement is that contractions no longer use pseudo functions to achieve their own local scope, but that there is now a dedicated structure for that representing an in-lined function.

Bug Fixes

  • Python3.6: Fix, async for was not yet implemented for async generators.

  • Fix, functions with keyword arguments where the value was determined to be a static raise could crash the compiler.

  • Detect using MinGW64 32 bits C compiler being used with 64 bits Python with better error message.

  • Fix, when extracting side effects of a static raise, extract them more recursively to catch expressions that themselves have no code generation being used. This fixes at least static raises in keyword arguments of a function call.

  • Compatibility: Added support for proper operation of pkgutil.get_data by implementing get_data in our meta path based loader.

  • Compatibility: Added __spec__ module attribute was previously missing, present on Python3.4 and higher.

  • Compatibility: Made __loader__ module attribute set when the module is loading already.

  • Standalone: Resolve the @rpath and @loader_path from otool on macOS manually to actual paths, which adds support for libraries compiled with that.

  • Fix, nested functions calling super could crash the compiler.

  • Fix, could not use --recurse-directory with arguments that had a trailing slash.

  • Fix, using --recurse-directory on packages that are not in the search crashed the compiler.

  • Compatibility: Python2 set and dict contractions were using extra frames like Python3 does, but those are not needed.

  • Standalone: Fix, the way PYTHONHOME was set on Windows had no effect, which allowed the compiled binary to access the original installation still.

  • Standalone: Added some newly discovered missing hidden dependencies of extension modules.

  • Compatibility: The name mangling of private names (e.g. __var) in classes was applied to variable names, and function declarations, but not to classes yet.

  • Python3.6: Fix, added support for list contractions with await expressions in async generators.

  • Python3.6: Fix, async for was not working in async generators yet.

  • Fix, for module tracebacks, we output the module name <module name> instead of merely <module>, but if the module was in a package, that was not indicated. Now it is <module>.

  • Windows: The cache directory could be unicode which then failed to pass as an argument to scons. We now encode such names as UTF-8 and decode in Scons afterwards, solving the problem in a generic way.

  • Standalone: Need to recursively resolve shared libraries with ldd, otherwise not all could be included.

  • Standalone: Make sure sys.path has no references to CPython compile time paths, or else things may work on the compiling machine, but not on another.

  • Standalone: Added various missing dependencies.

  • Standalone: Wasn’t considering the DLLs directory for standard library extensions for freezing, which would leave out these.

  • Compatibility: For __future__ imports the __import__ function was called more than once.


  • Contractions are now all properly inlined and allow for optimization as if they were fully local. This should give better code in some cases.

  • Classes are now all building their locals dictionary inline to the using scope, allowing for more compact code.

  • The dictionary API was not used in module template code, although it helps to generate more compact code.

New Features

  • Experimental support for building platform dependent wheel distribution.

    python --command-packages=nuitka.distutils clean -a bdist_nuitka

    Use with caution, this is incomplete work.

  • Experimental support for running tests against compiled installation with nose and py.test.

  • When specifying what to recurse to, now patterns can be used, e.g. like this --recurse-not-to=*.tests which will skip all tests in submodules from compilation.

  • By setting NUITKA_PACKAGE_packagename=/some/path the __path__ of packages can be extended automatically in order to allow and load uncompiled sources from another location. This can be e.g. a tests sub-package or other plugins.

  • By default when creating a module, now also a module.pyi file is created that contains all imported modules. This should be deployed alongside the extension module, so that standalone mode creation can benefit from knowing the dependencies of compiled code.

  • Added option --plugin-list that was mentioned in the help output, but still missing so far.

  • The import tracing of the hints module has achieved experimental status and can be used to test compatibility with regards to import behavior.


  • Rename tree and codegen Helper modules to unique names, making them easier to work with.

  • Share the code that decides to not warn for standard library paths with more warnings.

  • Use the bool enum definition of Python2 which is more elegant than ours.

  • Move quality tools, auto-format, isort, etc. to the namespace.

  • Move output comparison tool to the namespace.

  • Made frame code generation capable of using nested frames, allowing the real inline of classes and contraction bodies, instead of “direct” calls to pseudo functions being used.

  • Proper base classes for functions that are entry points, and functions that are merely a local expression using return statements.


  • The search mode with pattern, was not working anymore.

  • Resume hash values now consider the Python version too.

  • Added test that covers using test runners like nose and py.test with Nuitka compiled extension modules.


  • Added support for Scons 3.0 and running Scons with Python3.5 or higher. The option to specify the Python to use for scons has been renamed to reflect that it may also be a Python3 now. Only for Python3.2 to Python3.4 we now need another Python installation.

  • Made recursion the default for --recurse-directory with packages. Before you also had to tell it to recurse into that package or else it would only include the top level package, but nothing below.

  • Updated the man pages, correct mentions of its C++ to C and don’t use now deprecated options.

  • Updated the help output which still said that standalone mode implies recursion into standard library, which is no longer true and even not recommended.

  • Added option to disable the output of .pyi file when creating an extension module.

  • Removed Ubuntu Wily package download, no longer supported by Ubuntu.


This release was done to get the fixes and new features out for testing. There is work started that should make generators use an explicit extra stack via pointer, and restore instruction state via goto dispatchers at function entry, but that is not complete.

This feature, dubbed “goto generators” will remove the need for fibers (which is itself a lot of code), reduce the memory footprint at run time for anything that uses a lot of generators, or coroutines.

Integrating with distutils is also a new thing, and once completed will make use of Nuitka for existing projects automatic and trivial to do. There is a lot missing for that goal, but we will get there.

Also, documenting how to run tests against compiled code, if that test code lives inside of that package, will make a huge difference, as that will make it easier for people to torture Nuitka with their own test cases.

And then of course, nested frames now mean that every function could be inlined, which was previously not possible due to collisions of frames. This will pave the route for better optimization in those cases in future releases.

The experimental features will require more work, but should make it easier to use Nuitka for existing projects. Future releases will make integrating Nuitka dead simple, or that is the hope.

And last but not least, now that Scons works with Python3, chances are that Nuitka will more often work out the of the box. The older Python3 versions that still retain the issue are not very widespread.

Nuitka Release 0.5.27

This release comes a lot of bug fixes and improvements.

Bug Fixes

  • Fix, need to add recursed modules immediately to the working set, or else they might first be processed in second pass, where global names that are locally assigned, are optimized to the built-in names although that should not happen. Fixed in already.

  • Fix, the accelerated call of methods could crash for some special types. This had been a regress of 0.5.25, but only happens with custom extension types. Fixed in already.

  • Python3.5: For async def functions parameter variables could fail to properly work with in-place assignments to them. Fixed in already.

  • Compatibility: Decorators that overload type checks didn’t pass the checks for compiled types. Now isinstance and as a result inspect module work fine for them.

  • Compatibility: Fix, imports from __init__ were crashing the compiler. You are not supposed to do them, because they duplicate the package code, but they work.

  • Compatibility: Fix, the super built-in on module level was crashing the compiler.

  • Standalone: For Linux, BSD and macOS extension modules and shared libraries using their own $ORIGIN to find loaded DLLs resulted in those not being included in the distribution.

  • Standalone: Added more missing implicit dependencies.

  • Standalone: Fix, implicit imports now also can be optional, as e.g. _tkinter if not installed. Only include those if available.

  • The --recompile-c-only was only working with C compiler as a backend, but not in the C++ compatibility fallback, where files get renamed. This prevented that edit and test debug approach with at least MSVC.

  • Plugins: The PyLint plug-in didn’t consider the symbolic name import-error but only the code F0401.

  • Implicit exception raises in conditional expressions would crash the compiler.

New Features

  • Added support for Visual Studio 2017.

  • Added option --python2-for-scons to specify the Python2 execute to use for calling Scons. This should allow using Anaconda Python for that task.


  • References to known unassigned variables are now statically optimized to exception raises and warned about if the according option is enabled.

  • Non-hashable keys in dictionaries are now statically optimized to exception raises and warned about if the according option is enabled.

  • Enable forward propagation for classes too, resulting in some classes to create only static dictionaries. Currently this never happens for Python3, but it will, once we can statically optimize __prepare__ too.

  • Enable inlining of class dictionary creations if they are mere return statements of the created dictionary. Currently this never happens for Python3, see above for why.

  • Python2: Selecting the metaclass is now visible in the tree and can be statically optimized.

  • For executables, we now also use a free list for traceback objects, which also makes exception cases slightly faster.

  • Generator expressions no longer require the use of a function call with a .0 argument value to carry the iterator value, instead their creation is directly inlined.

  • Remove “pass through” frames for Python2 list contractions, they are no longer needed. Minimal gain for generated code, but more lightweight at compile time.

  • When compiling Windows x64 with MinGW64 a link library needs to be created for linking against the Python DLL. This one is now cached and re-used if already done.

  • Use common code for NameError and UnboundLocalError exception code raises. In some cases it was creating the full string at compile time, in others at run time. Since the later is more efficient in terms of code size, we now use that everywhere, saving a bit of binary size.

  • Make sure to release unused functions from a module. This saves memory and can be decided after a full pass.

  • Avoid using OrderedDict in a couple of places, where they are not needed, but can be replaced with a later sorting, e.g. temporary variables by name, to achieve deterministic output. This saves memory at compile time.

  • Add specialized return nodes for the most frequent constant values, which are None, True, and False. Also a general one, for constant value return, which avoids the constant references. This saves quite a bit of memory and makes traversal of the tree a lot faster, due to not having any child nodes for the new forms of return statements.

  • Previously the empty dictionary constant reference was specialized to save memory. Now we also specialize empty set, list, and tuple constants to the same end. Also the hack to make is not say that {} is {} was made more general, mutable constant references and now known to never alias.

  • The source references can be marked internal, which means that they should never be visible to the user, but that was tracked as a flag to each of the many source references attached to each node in the tree. Making a special class for internal references avoids storing this in the object, but instead it’s now a class property.

  • The nodes for named variable reference, assignment, and deletion got split into separate nodes, one to be used before the actual variable can be determined during tree building, and one for use later on. This makes their API clearer and saves a tiny bit of memory at compile time.

  • Also eliminated target variable references, which were pseudo children of assignments and deletion nodes for variable names, that didn’t really do much, but consume processing time and memory.

  • Added optimization for calls to staticmethod and classmethod built-in methods along with type shapes.

  • Added optimization for open built-in on Python3, also adding the type shape file for the result.

  • Added optimization for bytearray built-in and constant values. These mutable constants can now be compile time computed as well.

  • Added optimization for frozenset built-in and constant values. These mutable constants can now be compile time computed as well.

  • Added optimization for divmod built-in.

  • Treat all built-in constant types, e.g. type itself as a constant. So far we did this only for constant values types, but of course this applies to all types, giving slightly more compact code for their uses.

  • Detect static raises if iterating over non-iterables and warn about them if the option is enabled.

  • Split of locals node into different types, one which needs the updated value, and one which just makes a copy. Properly track if a functions needs an updated locals dict, and if it doesn’t, don’t use that. This gives more efficient code for Python2 classes, and exec using functions in Python2.

  • Build all constant values without use of the pickle module which has a lot more overhead than marshal, instead use that for too large long values, non-UTF-8 unicode values, nan float, etc.

  • Detect the linker arch for all Linux platforms using objdump instead of only a hand few hard coded ones.


  • The use of INCREASE_REFCOUNT got fully eliminated.

  • Use functions not vulenerable for buffer overflow. This is generally good and avoids warnings given on OpenBSD during linking.

  • Variable closure for classes is different from all functions, don’t handle the difference in the base class, but for class nodes only.

  • Make sure mayBeNone doesn’t return None which means normally “unclear”, but False instead, since it’s always clear for those cases.

  • Comparison nodes were using the general comparison node as a base class, but now a proper base class was added instead, allowing for cleaner code.

  • Valgrind test runners got changed to using proper tool namespace for their code and share it.

  • Made construct case generation code common testing code for reuse in the speedcenter web site. The code also has minor beauty bugs which will then become fixable.

  • Use appdirs package to determine place to store the downloaded copy of depends.exe.

  • The code still mentioned C++ in a lot of places, in comments or identifiers, which might be confusing readers of the code.

  • Code objects now carry all information necessary for their creation, and no longer need to access their parent to determine flag values. That parent is subject to change in the future.

  • Our import sorting wrapper automatically detects imports that could be local and makes them so, removing a few existing ones and preventing further ones on the future.

  • Cleanups and annotations to become Python3 PyLint clean as well. This found e.g. that source code references only had __cmp__ and need rich comparison to be fully portable.


  • The test runner for construct tests got cleaned up and the constructs now avoid using xrange so as to not need conversion for Python3 execution as much.

  • The main test runner got cleaned up and uses common code making it more versatile and robust.

  • Do not run test in debugger if CPython also segfaulted executing the test, then it’s not a Nuitka issue, so we can ignore that.

  • Improve the way the Python to test with is found in the main test runner, prefer the running interpreter, then PATH and registry on Windows, this will find the interesting version more often.

  • Added support for “” to ignore the inline copies of code, they are not under our control.

  • The test runner for Valgrind got merged with the usage for constructs and uses common code now.

  • Construct generation is now common code, intended for sharing it with the Speedcenter web site generation.

  • Rebased Python 3.6 test suite to 3.6.1 as that is the Python generally used now.


  • Added inline copy of appdirs package from PyPI.

  • Added credits for RedBaron and isort.

  • The --experimental flag is now creating a list of indications and more than one can be used that way.

  • The PyLint runner can also work with Python3 pylint.

  • The Nuitka Speedcenter got more fine tuning and produces more tags to more easily identify trends in results. This needs to become more visible though.

  • The MSI files are also built on AppVeyor, where their building will not depend on me booting Windows. Getting these artifacts as downloads will be the next step.


This release improves many areas. The variable closure taking is now fully transparent due to different node types, the memory usage dropped again, a few obvious missing static optimizations were added, and many built-ins were completed.

This release again improves the scalability of Nuitka, which again uses less memory than before, although not an as big jump as before.

This does not extend or use special C code generation for bool or any type yet, which still needs design decisions to proceed and will come in a later release.

Nuitka Release 0.5.26

This release comes after a long time and contains large amounts of changes in all areas. The driving goal was to prepare generating C specific code, which is still not the case, but this is very likely going to change soon. However this release improves all aspects.

Bug Fixes

  • Compatibility: Fix, for star imports didn’t check the values from the __all__ iterable, if they were string values which could cause problems at run time.

    # Module level
    __all__ = (1,)
    # ...
    # other module:
    from module import *
  • Fix, for star imports, also didn’t check for values from __all__ if they actually exist in the original values.

  • Corner cases of imports should work a lot more precise, as the level of compatibility for calls to __import__ went from absurd to insane.

  • Windows: Fixed detection of uninstalled Python versions (not for all users and DLL is not in system directory). This of course only affected the accelerated mode, not standalone mode.

  • Windows: Scan directories for .pyd files for used DLLs as well. This should make the PyQt5 wheel work.

  • Python3.5: Fix, coroutines could have different code objects for the object and the frame using by it.

  • Fix, slices with built-in names crashed the compiler.

  • Fix, the C11 via C++ compatibility uses symlinks tp C++ filenames where possible instead of making a copy from the C source. However, even on Linux that may not be allowed, e.g. on a DOS file system. Added fallback to using full copy in that case.

  • Python3.5: Fix coroutines to close the “yield from” where an exception is thrown into them.

  • Python3: Fix, list contractions should have their own frame too.

  • Linux: Copy the “rpath” of compiling Python binary to the created binary. This will make compiled binaries using uninstalled Python versions transparently find the Python shared library.

  • Standalone: Add the “rpath” of the compiling Python binary to the search path when checking for DLL dependencies on Linux. This fixes standalone support for Travis and Anaconda on Linux.

  • Scons: When calling scons, also try to locate a Python2 binary to overcome a potential Python3 virtualenv in which Nuitka is running.

  • Standalone: Ignore more Windows only encodings on non-Windows.

New Features

  • Support for Python 3.6 with only few corner cases not supported yet.

  • Added options --python-arch to pick 32 or 64 bits Python target of the --python-version argument.

  • Added support for more kinds of virtualenv configurations.

  • Uninstalled Python versions such as Anaconda will work fine in accelerated mode, except on Windows.


  • The node tree children are no longer stored in a separate dictionary, but in the instance dictionary as attributes, making the tree more lightweight and in principle faster to access. This also saved about 6% of the memory usage.

  • The memory usage of Nuitka for the Python part has fallen by roughly 40% due to the use of new style classes, and slots where that is possible (some classes use multiple inheritance, where they don’t work), and generally by reducing useless members e.g. in source code references. This of course also will make things compiled faster (the C compilation of course is not affected by this.)

  • The code generation for frames was creating the dictionary for the raised exception by making a dictionary and then adding all variables, each tested to be set. This was a lot of code for each frame specific, and has been replaced by a generic “attach” mechanism which merely stores the values, and only takes a reference. When asked for frame locals, it only then builds the dictionary. So this is now only done, when that is absolutely necessary, which it normally never is. This of course makes the C code much less verbose, and actual handling of exceptions much more efficient.

  • For imports, we now detect for built-in modules, that their import cannot fail, and if name lookups can fail. This leads to less code generated for error handling of these. The following code now e.g. fully detects that no ImportError or AttributeError will occur.

        from __builtin__ import len
    except ImportError:
        from builtins import len
  • Added more type shapes for built-in type calls. These will improve type tracing.

  • Compiled frames now have a free list mechanism that should speed up frames that recurse and frames that exit with exceptions. In case of an exception, the frame ownership is immediately transferred to the exception making it easier to deal with.

  • The free list implementations have been merged into a new common one that can be used via macro expansion. It is now type agnostic and be slightly more efficient too.

  • Also optimize “true” division and “floor division”, not only the default division of Python2.

  • Removed the need for statement context during code generation making it less memory intensive and faster.


  • Now always uses the __import__ built-in node for all kinds of imports and directly optimizes and recursion into other modules based on that kind of node, instead of a static variant. This removes duplication and some incompatibility regarding defaults usage when doing the actual imports at run time.

  • Split the expression node bases and mixin classes to a dedicated module, moving methods that only belong to expressions outside of the node base, making for a cleaner class hierarchy.

  • Cleaned up the class structure of nodes, added base classes for typical compositions, e.g. expression with and without children, computation based on built-in, etc. while also checking proper ordering of base classes in the metaclass.

  • Moved directory and file operations to dedicated module, making also sure it is more generally used. This makes it easier to make more error resilient deletions of directories on e.g. Windows, where locks tend to live for short times beyond program ends, requiring second attempts.

  • Code generation for existing supported types, PyObject *, PyObject **, and struct Nuitka_CellObject * is now done via a C type class hierarchy instead of elif sequences.

  • Closure taking is now always done immediately correctly and references are take for closure variables still needed, making sure the tree is correct and needs no finalization.

  • When doing variable traces, initialize more traces immediately so it can be more reliable.

  • Code to setup a function for local variables and clean it up has been made common code instead of many similar copies.

  • The code was treating the f_executing frame member as if it were a counter with increases and decreases. Turn it into a mere boolean value and hide its usage behind helper functions.

  • The “maybe local variables” are no more. They were replaced by a new locals dict access node with a fallback to a module or closure variable should the dictionary not contain the name. This avoids many ugly checks to not do certain things for that kind of variable.

  • We now detect “exec” and “unqualified exec” as well as “star import” ahead of time as flags of the function to be created. We no longer need to mark functions as we go.

  • Handle “true”, “floor” and normal division properly by applying future flags to decide which one to use.

  • We now use symbolic identifiers in all PyLint annotations.

  • The release scripts started to move into so they get PyLint checks, auto-format and proper code reuse.

  • The use of INCREASE_REFCOUNT_X was removed, it got replaced with proper Py_XINCREF usages.

  • The use of INCREASE_REFCOUNT got reduced further, e.g. no generated code uses it anymore, and only a few compiled types do. The function was once required before “C-ish” lifted the need to do everything in one single function call.


  • More robust deletion of directories, temporary stages used by CPython test suites, and standalone directories during test execution.

  • Moved tests common code into namespace and use it from there. The code now is allowed to use nuitka.utils and therefore often better implementations.

  • Made standalone binaries robust against GTK theme access, checking the Python binary (some files do that),


  • Added repository for Ubuntu Zesty (17.04) for download.

  • Added support for testing with Travis to complement the internal Buildbot based infrastructure and have pull requests on GitHub automatically tested before merge.

  • The factory branch is now also on GitHub.

  • Removed MSI for Python3.4 32 bits. It seems impossible to co-install this one with the 64 bits variant. All other versions are provided for both bit sizes still.


This release marks huge progress. The node tree is now absolutely clean, the variable closure taking is fully represented, and code generation is prepared to add another type, e.g. for bool for which work has already started.

On a practical level, the scalability of the release will have increased very much, as this uses so much less memory, generates simpler C code, while at the same time getting faster for the exception cases.

Coming releases will expand on the work of this release.

Frame objects should be allowed to be nested inside a function for better re-formulations of classes and contractions of all kinds, as well as real inline of functions, even if they could raise.

The memory savings could be even larger, if we stopped doing multiple inheritance for more node types. The __slots__ were and the child API change could potentially make things not only more compact, but faster to use too.

And also once special C code generation for bool is done, it will set the stage for more types to follow (int, float, etc). Only this will finally start to give the C type speed we are looking for.

Until then, this release marks a huge cleanup and progress to what we already had, as well as preparing the big jump in speed.

Nuitka Release 0.5.25

This release contains a huge amount of bug fixes, lots of optimization gains, and many new features. It also presents many organisational improvements, and many cleanups.

Bug Fixes

  • Python3.5: Coroutine methods using super were crashing the compiler. Fixed in already.

  • Python3.3: Generator return values were not properly transmitted in case of tuple or StopIteration values.

  • Python3.5: Better interoperability between compiled coroutines and uncompiled generator coroutines.

  • Python3.5: Added support to compile in Python debug mode under Windows too.

  • Generators with arguments were using two code objects, one with, and one without the CO_NOFREE flag, one for the generator object creating function, and one for the generator object.

  • Python3.5: The duplicate code objects for generators with arguments lead to interoperability issues with between such compiled generator coroutines and compiled coroutines. Fixed in already.

  • Standalone: On some Linux variants, e.g. Debian Stretch and Gentoo, the linker needs more flags to really compile to a binary with RPATH.

  • Compatibility: For set literal values, insertion order is wrong on some versions of Python, we now detect the bug and emulate it if necessary, previous Nuitka was always correct, but incompatible.

    {1, 1.0}.pop()  # the only element of the set should be 1
  • Windows: Make the batch files detect where they live at run time, instead of during, making it possible to use them for all cases.

  • Standalone: Added package paths to DLL scan for depends.exe, as with wheels there now sometimes live important DLLs too.

  • Fix, the clang mode was regressed and didn’t work anymore, breaking the macOS support entirely.

  • Compatibility: For imports, we were passing for locals argument a real dictionary with actual values. That is not what CPython does, so stopped doing it.

  • Fix, for raised exceptions not passing the validity tests, they could be used after free, causing crashes.

  • Fix, the environment CC wasn’t working unless also specifying CXX.

  • Windows: The value of __file__ in module mode was wrong, and didn’t point to the compiled module.

  • Windows: Better support for --python-debug for installations that have both variants, it is now possible to switch to the right variant.

New Features

  • Added parsing for shebang to Nuitka. When compiling an executable, now Nuitka will check of the #! portion indicates a different Python version and ask the user to clarify with --python-version in case of a mismatch.

  • Added support for Python flag --python-flag=-O, which allows to disable assertions and remove doc strings.


  • Faster method calls, combining attribute lookup and method call into one, where order of evaluation with arguments doesn’t matter. This gives really huge relative speedups for method calls with no arguments.

  • Faster attribute lookup in general for object descendants, which is all new style classes, and all built-in types.

  • Added dedicated xrange built-in implementation for Python2 and range for Python3. This makes those faster while also solving ordering problems when creating constants of these types.

  • Faster sum again, using quick iteration interface and specialized quick iteration code for typical standard type containers, tuple and list.

  • Compiled generators were making sure StopIteration was set after their iteration, although most users were only going to clear it. Now only the send method, which really needs that does it. This speed up the closing of generators quite a bit.

  • Compiled generators were preparing a throw into non-started compilers, to be checked for immediately after their start. This is now handled in a generic way for all generators, saving code and execution time in the normal case.

  • Compiled generators were applying checks only useful for manual send calls even during iteration, slowing them down.

  • Compiled generators could duplicate code objects due to handling a flag for closure variables differently.

  • For compiled frames, the f_trace is not writable, but was taking and releasing references to what must be None, which is not useful.

  • Not passing locals to import calls make it less code and faster too.


  • This release also prepares Python 3.6 support, it includes full language support on the level of CPython 3.6.0 with the sole exception of the new generator coroutines.

  • The improved mode is now the default, and full compatibility is now the option, used by test suites. For syntax errors, improved mode is always used, and for test suites, now only the error message is compared, but not call stack or caret positioning anymore.

  • Removed long deprecated option “–no-optimization”. Code generation too frequently depends on not seeing unoptimized code. This has been hidden and broken long enough to finally remove it.

  • Added support for Python3.5 numbers to Speedcenter. There are now also tags for speedcenter, indicating how well “develop” branch fares in comparison to the stable branch.

  • With a new tool, source code and Developer Manual contents can be kept in sync, so that descriptions can be quoted there. Eventually a full Sphinx documentation might become available, but for now this makes it workable.

  • Added repository for Ubuntu Yakkety (16.10) for download.

  • Added repository for Fedora 25 for download.


  • Moved the tools to compare CPython output, to sort import statements (isort) to auto-format the source code (Redbaron usage), and to check with PyLint to a common new package, runnable with __main__ modules and dedicated runners in bin directory.

  • The tools now share code to find source files, or have it for the first time, and other things, e.g. finding needed binaries on Windows installations.

  • No longer patch traceback objects dealloc function. Should not be needed anymore, and most probably was only bug hiding.

  • Moved handling of ast nodes related to import handling to the proper reformulation module.

  • Moved statement generation code to helpers module, making it accessible without cyclic dependencies that require local imports.

  • Removed deprecated method for getting constant code objects in favor of the new way of doing it. Both methods were still used, making it harder to analyse.

  • Removed useless temporary variable initializations from complex call helper internal functions. They worked around code generation issues that have long been solved.

  • The ABI flags are no longer passed to Scons together with the version.


  • Windows: Added support to detect and to switch debug Python where available to also be able to execute reference counting tests.

  • Added the CPython 3.3 test suite, after cleaning up the worst bits of it, and added the brandnew 3.6 test suite with a minimal set of changes.

  • Use the original 3.4 test suite instead of the one that comes from Debian as it has patched quite a few issues that never made it upstream, and might cause crashes.

  • More construct tests, making a difference between old style classes, which have instances and new style classes, with their objects.

  • It is now possible to run a test program with Python3 and Valgrind.


The quick iteration is a precursor to generally faster iteration over unknown object iterables. Expanding this to general code generation, and not just the sum built-in, might yield significant gains for normal code in the future, once we do code generation based on type inference.

The faster method calls complete work that was already prepared in this domain and also will be expanded to more types than compiled functions. More work will be needed to round this up.

Adding support for 3.6.0 in the early stages of its release, made sure we pretty much have support for it ready right after release. This is always a huge amount of work, and it’s good to catch up.

This release is again a significant improvement in performance, and is very important to clean up open ends. Now the focus of coming releases will now be on both structural optimization, e.g. taking advantage of the iterator tracing, and specialized code generation, e.g. for those iterations really necessary to use quick iteration code.

Nuitka Release 0.5.24

This release is again focusing on optimization, this time very heavily on the generator performance, which was found to be much slower than CPython for some cases. Also there is the usual compatibility work and improvements for Pure C support.

Bug Fixes

  • Windows: The 3.5.2 coroutine new protocol implementation was using the wrapper from CPython, but it’s not part of the ABI on Windows. Have our own instead. Fixed in already.

  • Windows: Fixed second compilation with MSVC failing. The files renamed to be C++ files already existed, crashing the compilation. Fixed in already.

  • Mac OS: Fixed creating extension modules with .so suffix. This is now properly determined by looking at the importer details, leading to correct suffix on all platforms. Fixed in already.

  • Debian: Don’t depend on a C++ compiler primarily anymore, the C compiler from GNU or clang will do too. Fixed in already.

  • Pure C: Adapted scons compiler detecting to properly consider C11 compilers from the environment, and more gracefully report things.


  • Python2: Generators were saving and restoring exceptions, updating the variables sys.exc_type for every context switch, making it really slow, as these are 3 dictionary updates, normally not needed. Now it’s only doing it if it means a change.

  • Sped up creating generators, coroutines and coroutines by attaching the closure variable storage directly to the object, using one variable size allocation, instead of two, once of which was a standard malloc. This makes creating them easier and avoids maintaining the closure pointer entirely.

  • Using dedicated compiled cell implementation similar to PyCellObject but fully under our control. This allowed for smaller code generated, while still giving a slight performance improvement.

  • Added free list implementation to cache generator, coroutines, and function objects, avoiding the need to create and delete this kind of objects in a loop.

  • Added support for the built-in sum, making slight optimizations to be much faster when iterating over lists and tuples, as well as fast long sum for Python2, and much faster bool sums too. This is using a prototype version of a “qiter” concept.

  • Provide type shape for xrange calls that are not constant too, allowing for better optimization related to those.


  • Added workarounds for locks being held by Virus Scanners on Windows to our test runner.

  • Enhanced constructs that test generator expressions to more clearly show the actual construct cost.

  • Added construct tests for the sum built-in on various types of int containers, making sure we can do all of those really fast.


This release improves very heavily on generators in Nuitka. The memory allocator is used more cleverly, and free lists all around save a lot of interactions with it. More work lies ahead in this field, as these are not yet as fast as they should be. However, at least Nuitka should be faster than CPython for these kind of usages now.

Also, proper pure C in the Scons is relatively important to cover more of the rarer use cases, where the C compiler is too old.

The most important part is actually how sum optimization is staging a new kind of approach for code generation. This could become the standard code for iterators in loops eventually, making for loops even faster. This will be for future releases to expand.

Nuitka Release 0.5.23

This release is focusing on optimization, the most significant part for the users being enhanced scalability due to memory usage, but also break through structural improvements for static analysis of iterators and the debut of type shapes and value shapes, giving way to “shape tracing”.

Bug Fixes

  • Fix support Python 3.5.2 coroutine changes. The checks got added for improved mode for older 3.5.x, the new protocol is only supported when run with that version or higher.

  • Fix, was falsely optimizing away unused iterations for non-iterable compile time constants.

    iter(1)  # needs to raise.
  • Python3: Fix, eval must not attempt to strip memoryviews. The was preventing it from working with that type.

  • Fix, calling type without any arguments was crashing the compiler. Also the exception raised for anything but 1 or 3 arguments was claiming that only 3 arguments were allowed, which is not the compatible thing.

  • Python3.5: Fix, follow enhanced error checking for complex call handling of star arguments.

  • Compatibility: The from x import x, y re-formulation was doing two __import__ calls instead of re-using the module value.


  • Uses only about 66% of the memory compared to last release, which is very important step for scalability independent of re-loading. This was achieved by making sure to break loop traces and their reference cycle when they become unused.

  • Properly detect the len of multiplications at compile time from newly introduces value shapes, so that this is e.g. statically optimized.

    print(len("*" * 10000000000))
  • Due to newly introduced type shapes, len and iter now properly detect more often if values will raise or not, and warn about detected raises.

    iter(len(something))  # Will always raise
  • Due to newly introduced “iterator tracing”, we can now properly detect if the length of an unpacking matches its source or not. This allows to remove the check of the generic re-formulations of unpackings at compile time.

    a, b = b, a  # Will never raise due to unpacking
    a, b = b, a, c  # Will always raise, 3 items cannot unpack to 2
  • Added support for optimization of the xrange built-in for Python2.

  • Python2: Added support for xrange iterable constant values, pre-building those constants ahead of time.

  • Python3: Added support and range iterable constant values, pre-building those constants ahead of time. This brings optimization support for Python3 ranges to what was available for Python2 already.

  • Avoid having a special node variange for range with no arguments, but create the exception raising node directly.

  • Specialized constant value nodes are using less generic implementations to query e.g. their length or iteration capabilities, which should speed up many checks on them.

  • Added support for the format built-in.

  • Python3: Added support for the ascii built-in.


  • The movement to pure C got the final big push. All C++ only idoms of C++ were removed, and everything works with C11 compilers. A C++03 compiler can be used as a fallback, in case of MSVC or too old gcc for instance.

  • Using pure C, MinGW64 6x is now working properly. The latest version had problems with hypot related changes in the C++ standard library. Using C11 solves that.

  • This release also prepares Python 3.6 support, it includes full language support on the level of CPython 3.6.0b1.

  • The CPython 3.6 test suite was run with Python 3.5 to ensure bug level compatibility, and had a few findings of incompatibilities.


  • The last holdouts of classes in Nuitka were removed, and many idioms of C++ were stopped using.

  • Moved range related helper functions to a dedicated include file.

  • Using str is not bytes to detect Python3 str handling or actual bytes type existence.

  • Trace collections were using a mix-in that was merged with the base class that every user of it was having.


  • Added more static optimization tests, a lot more has become feasible to decide at run time, and is now done. These are to detect regressions in that domain.

  • The CPython 3.6 test suite is now also run with CPython 3.5 which found some incompatibilities.


This release marks a huge step forward. We are having the structure for type inference now. This will expand in coming releases to cover more cases, and there are many low hanging fruits for optimization. Specialized codes for variable versions of certain known shapes seems feasible now.

Then there is also the move towards pure C. This will make the backend compilation lighter, but due to using C11, we will not suffer any loss of convenience compared to “C-ish”. The plan is to use continue to use C++ for compilation for compilers not capable of supporting C11.

The amount of static analysis done in Nuitka is now going to quickly expand, with more and more constructs predicted to raise errors or simplified. This will be an ongoing activity, as many types of expressions need to be enhanced, and only one missing will not let it optimize as well.

Also, it seems about time to add dedicated code for specific types to be as fast as C code. This opens up vast possibilities for acceleration and will lead us to zero overhead C bindings eventually. But initially the drive is towards enhanced import analysis, to become able to know the precise module expected to be imported, and derive type information from this.

The coming work will attack to start whole program optimization, as well as enhanced local value shape analysis, as well specialized type code generation, which will make Nuitka improve speed.

Nuitka Release 0.5.22

This release is mostly an intermediate release on the way to the large goal of having per module compilation that is cacheable and requires far less memory for large programs. This is currently in progress, but required many changes that are in this release, more will be needed.

It also contains a bunch of bug fixes and enhancements that are worth to be released, and the next changes are going to be more invasive.

Bug Fixes

  • Compatibility: Classes with decorated __new__ functions could miss out on the staticmethod decorator that is implicit. It’s now applied always, unless of course it’s already done manually. This corrects an issue found with Pandas. Fixed in already.

  • Standalone: For at least Python 3.4 or higher, it could happen that the locale needed was not importable. Fixed in already.

  • Compatibility: Do not falsely assume that not expressions cannot raise on boolean expressions, since those arguments might raise during creation. This could lead to wrong optimization. Fixed in already.

  • Standalone: Do not include system specific C libraries in the distribution created. This would lead to problems for some configurations on Linux in cases the glibc is no longer compatible with newer or older kernels. Fixed in already.

  • The --recurse-directory option didn’t check with decision mechanisms for module inclusion, making it impossible to avoid some things.


  • Introduced specialized constant classes for empty dictionaries and other special constants, e.g. “True” and “False”, so that they can have more hard coded properties and save memory by sharing constant values.

  • The “technical” sharing of a variable is only consider for variables that had some sharing going in the first place, speeing things up quite a bit for that still critical check.

  • Memory savings coming from enhanced trace storage are already visible at about 1%. That is not as much as the reloading will mean, but still helpful to use less overall.


  • The global variable registry was removed. It was in the way of unloading and reloading modules easily. Instead variables are now attached to their owner and referenced by other users. When they are released, these variables are released.

  • Global variable traces were removed. Instead each variable has a list of the traces attached to it. For non-shared variables, this allows to sooner tell attributes of those variables, allowing for sooner optimization of them.

  • No longer trace all initial users of a variable, just merely if there were such and if it constitutes sharing syntactically too. Not only does this save memory, it avoids useless references of the variable to functions that stop using it due to optimization.

  • Create constant nodes via a factory function to avoid non-special instances where variants exist that would be faster to use.

  • Moved the C string functions to a proper nuitka.utils.CStrings package as we use it for better code names of functions and modules.

  • Made functions and explicit child node of modules, which makes their use more generic, esp. for re-loading modules.

  • Have a dedicated function for building frame nodes, making it easier to see where they are created.


This release is the result of a couple of months work, and somewhat means that proper re-loading of cached results is becoming in sight. The reloading of modules still fails for some things, and more changes will be needed, but with that out of the way, Nuitka’s footprint is about to drop and making it then absolutely scalable. Something considered very important before starting to trace more information about values.

This next thing big ought to be one thing that structurally holds Nuitka back from generating C level performance code with say integer operations.

Nuitka Release 0.5.21

This release focused on scalability work. Making Nuitka more usable in the common case, and covering more standalone use cases.

Bug Fixes

  • Windows: Support for newer MinGW64 was broken by a workaround for older MinGW64 versions.

  • Compatibility: Added support for the (unofficial) C-Python API Py_GetArgcArgv that was causing prctl module to fail loading on ARM platforms.

  • Compatibility: The proper error message template for complex call arguments is now detected as compile time. There are changes coming, that are already in some pre-releases of CPython.

  • Standalone: Wasn’t properly ignoring Tools and other directories in the standard library.

New Features

  • Windows: Detect the MinGW compiler arch and compare it to the Python arch. In case of a mismatch, the compiler is not used. Otherwise compilation or linking gives hard to understand errors. This also rules out MinGW32 as a compiler that can be used, as its arch doesn’t match MinGW64 32 bits variant.

  • Compile modules in two passes with the option to specify which modules will be considered for a second pass at all (compiled without program optimization) or even become bytecode.

  • The developer mode installation of Nuitka in develop mode with the command pip install -e nuitka_git_checkout_dir is now supported too.


  • Popular modules known to not be performance relevant are no longer C compiled, e.g. numpy.distutils and many others frequently imported (from some other module), but mostly not used and definitely not performance relevant.


  • The progress tracing and the memory tracing and now more clearly separate and therefore more readable.

  • Moved RPM related files to new rpm directory.

  • Moved documentation related files to doc directory.

  • Converted import sorting helper script to Python and made it run fast.


  • The Buildbot infrastructure for Nuitka was updated to Buildbot 0.8.12 and is now maintained up to date with Ansible.

  • Upgraded the Nuitka bug tracker to Roundup 1.5.1 to which I had previously contributed security fixes already active.

  • Added SSL certificates from Let’s Encrypt for the web server.


This release advances the scalability of Nuitka somewhat. The two pass approach does not yet carry all possible fruits. Caching of single pass compiled modules should follow for it to become consistently fast.

More work will be needed to achieve fast and scalable compilation, and that is going to remain the focus for some time.

Nuitka Release 0.5.20

This release is mostly about catching up with issues. Most address standalone problems with special modules, but there are also some general compatibility corrections, as well as important fixes for Python3.5 and coroutines and to improve compatibility with special Python variants like Anaconda under the Windows system.

Bug Fixes

  • Standalone Python3.5: The _decimal module at least is using a __name__ that doesn’t match the name at load time, causing programs that use it to crash.

  • Compatibility: For Python3.3 the __loader__ attribute is now set in all cases, and it needs to have a __module__ attribute. This makes inspection as done by e.g. flask working.

  • Standalone: Added missing hidden dependencies for Tkinter module, adding support for this to work properly.

  • Windows: Detecting the Python DLL and EXE used at compile time and preserving this information use during backend compilation. This should make sure we use the proper ones, and avoids hacks for specific Python variants, enhancing the support for Anaconda, WinPython, and CPython installations.

  • Windows: The --python-debug flag now properly detects if the run time is supporting things and error exits if it’s not available. For a CPython3.5 installation, it will switch between debug and non-debug Python binaries and DLLs.

  • Standalone: Added plug-in for the Pwm package to properly combine it into a single file, suitable for distribution.

  • Standalone: Packages from standard library, e.g. xml now have proper __path__ as a list and not as a string value, which breaks code of e.g. PyXML.

  • Standalone: Added missing dependency of twisted.protocols.tls.

  • Python3.5: When finalizing coroutines that were not finished, a corruption of its reference count could happen under some circumstances.

  • Standalone: Added missing DLL dependency of the uuid module at run time, which uses ctypes to load it.

New Features

  • Added support for Anaconda Python on this Linux. Both accelerated and standalone mode work now.

  • Added support for standalone mode on FreeBSD.

  • The plug-in framework was expanded with new features to allow addressing some specific issues.


  • Moved memory related stuff to dedicated utils package nuitka.utils.MemoryUsage as part of an effort to have more topical modules.

  • Plugins how have a dedicated module through which the core accesses the API, which was partially cleaned up.

  • No more “early” and “late” import detections for standalone mode. We now scan everything at the start.


This release focused on expanding plugins. These were then used to enhance the success of standalone compatibility. Eventually this should lead to a finished and documented plug-in API, which will open up the Nuitka core to easier hacks and more user contribution for these topics.

Nuitka Release 0.5.19

This release brings optimization improvements for dictionary using code. This is now lowering subscripts to dictionary accesses where possible and adds new code generation for known dictionary values. Besides this there is the usual range of bug fixes.

Bug Fixes

  • Fix, attribute assignments or deletions where the assigned value or the attribute source was statically raising crashed the compiler.

  • Fix, the order of evaluation during optimization was considered in the wrong order for attribute assignments source and value.

  • Windows: Fix, when g++ is the path, it was not used automatically, but now it is.

  • Windows: Detect the 32 bits variant of MinGW64 too.

  • Python3.4: The finalize of compiled generators could corrupt reference counts for shared generator objects. Fixed in already.

  • Python3.5: The finalize of compiled coroutines could corrupt reference counts for shared generator objects.


  • When a variable is known to have dictionary shape (assigned from a constant value, result of dict built-in, or a general dictionary creation), or the branch merge thereof, we lower subscripts from expecting mapping nodes to dictionary specific nodes. These generate more efficient code, and some are then known to not raise an exception.

    def someFunction(a, b):
        value = {a: b}
        value["c"] = 1
        return value

    The above function is not yet fully optimized (dictionary key/value tracing is not yet finished), however it at least knows that no exception can raise from assigning value["c"] anymore and creates more efficient code for the typical result = {} functions.

  • The use of “logical” sharing during optimization has been replaced with checks for actual sharing. So closure variables that were written to in dead code no longer inhibit optimization of the then no more shared local variable.

  • Global variable traces are now faster to decide definite writes without need to check traces for this each time.


  • No more using “logical sharing” allowed to remove that function entirely.

  • Using “technical sharing” less often for decisions during optimization and instead rely more often on proper variable registry.

  • Connected variables with their global variable trace statically avoid the need to check in variable registry for it.

  • Removed old and mostly unused “assume unclear locals” indications, we use global variable traces for this now.


This release aimed at dictionary tracing. As a first step, the value assign is now traced to have a dictionary shape, and this this then used to lower the operations which used to be normal subscript operations to mapping, but now can be more specific.

Making use of the dictionary values knowledge, tracing keys and values is not yet inside the scope, but expected to follow. We got the first signs of type inference here, but to really take advantage, more specific shape tracing will be needed.

Nuitka Release 0.5.18

This release mainly has a scalability focus. While there are few compatibility improvements, the larger goal has been to make Nuitka compilation and the final C compilation faster.

Bug Fixes

  • Compatibility: The nested arguments functions can now be called using their keyword arguments.

    def someFunction(a, (b, c)):
        return a, b, c
    someFunction(a=1, **{".1": (2, 3)})
  • Compatibility: Generators with Python3.4 or higher now also have a __del__ attribute, and therefore properly participate in finalization. This should improve their interactions with garbage collection reference cycles, although no issues had been observed so far.

  • Windows: Was outputting command line arguments debug information at program start. Fixed in already.


  • Code generated for parameter parsing is now a lot less verbose. Python level loops and conditionals to generate code for each variable has been replaced with C level generic code. This will speed up the backend compilation by a lot.

  • Function calls with constant arguments were speed up specifically, as their call is now fully prepared, and yet using less code. Variable arguments are also faster, and all defaulted arguments are also much faster. Method calls are not affected by these improvements though.

  • Nested argument functions now have a quick call entry point as well, making them faster to call too.

  • The slice built-in, and internal creation of slices (e.g. in re-formulations of Python3 slices as subscripts) cannot raise.

  • Standalone: Avoid inclusion of bytecode of unittest.test, sqlite3.test, distutils.test, and ensurepip. These are not needed, but simply bloat the amount of bytecode used on e.g. macOS.

  • Speed up compilation with Nuitka itself by avoid to copying and constructing variable lists as much as possible using an always accurate variable registry.


  • Nested argument functions of Python2 are now re-formulated into a wrapping function that directly calls the actual function body with the unpacking of nested arguments done in nodes explicitly. This allows for better optimization and checks of these steps and potential in-lining of these functions too.

  • Unified slice object creation and built-in slice nodes, these were two distinct nodes before.

  • The code generation for all statement kinds is now done via dispatching from a dictionary instead of long elif chains.

  • Named nodes more often consistently, e.g. all loop related nodes start with Loop now, making them easier to group.

  • Parameter specifications got simplified to work without variables where it is possible.


  • Nuitka is now available on the social code platforms gitlab as well.


Long standing weaknesses have been addressed in this release, also quite a few structural cleanups have been performed, e.g. strengthening the role of the variable registry to always be accurate, is groundlaying to further improvement of optimization.

However, this release cycle was mostly dedicated to performance of the actual compilation, and more accurate information was needed to e.g. not search for information that should be instant.

Upcoming releases will focus on usability issues and further optimization, it was nice however to see speedups of created code even from these scalability improvements.

Nuitka Release 0.5.17

This release is a major feature release, as it adds full support for Python3.5 and its coroutines. In addition, in order to properly support coroutines, the generator implementation got enhanced. On top of that, there is the usual range of corrections.

Bug Fixes

  • Windows: Command line arguments that are unicode strings were not properly working.

  • Compatibility: Fix, only the code object attached to exceptions contained all variable names, but not the one of the function object.

  • Python3: Support for virtualenv on Windows was using non-portable code and therefore failing.

  • The tree displayed with --display-tree duplicated all functions and did not resolve source lines for functions. It also displayed unused functions, which is not helpful.

  • Generators with parameters leaked C level memory for each instance of them leading to memory bloat for long running programs that use a lot of generators. Fixed in already.

  • Don’t drop positional arguments when called with --run, also make it an error if they are present without that option.

New Features

  • Added full support for Python3.5, coroutines work now too.


  • Optimized frame access of generators to not use both a local frame variable and the frame object stored in the generator object itself. This gave about 1% speed up to setting them up.

  • Avoid having multiple code objects for functions that can raise and have local variables. Previously one code object would be used to create the function (with parameter variable names only) and when raising an exception, another one would be used (with all local variable names). Creating them both at start-up was wasteful and also needed two tuples to be created, thus more constants setup code.

  • The entry point for generators is now shared code instead of being generated for each one over and over. This should make things more cache local and also results in less generated C code.

  • When creating frame codes, avoid working with strings, but use proper emission for less memory churn during code generation.


  • Updated the key for the Debian/Ubuntu repositories to remain valid for 2 more years.

  • Added support for Fedora 23.

  • MinGW32 is no more supported, use MinGW64 in the 32 bits variant, which has less issues.


  • Detecting function type ahead of times, allows to handle generators different from normal functions immediately.

  • Massive removal of code duplication between normal functions and generator functions. The later are now normal functions creating generator objects, which makes them much more lightweight.

  • The return statement in generators is now immediately set to the proper node as opposed to doing this in variable closure phase only. We can now use the ahead knowledge of the function type.

  • The nonlocal statement is now immediately checked for syntax errors as opposed to doing that only in variable closure phase.

  • The name of contraction making functions is no longer skewed to empty, but the real thing instead. The code name is solved differently now.

  • The local_locals mode for function node was removed, it was always true ever since Python2 list contractions stop using pseudo functions.

  • The outline nodes allowed to provide a body when creating them, although creating that body required using the outline node already to create temporary variables. Removed that argument.

  • Removed PyLint false positive annotations no more needed for PyLint 1.5 and solved some TODOs.

  • Code objects are now mostly created from specs (not yet complete) which are attached and shared between statement frames and function creations nodes, in order to have less guess work to do.


  • Added the CPython3.5 test suite.

  • Updated generated doctests to fix typos and use common code in all CPython test suites.


This release continues to address technical debt. Adding support for Python3.5 was the major driving force, while at the same time removing obstacles to the changes that were needed for coroutine support.

With Python3.5 sorted out, it will be time to focus on general optimization again, but there is more technical debt related to classes, so the cleanup has to continue.

Nuitka Release 0.5.16

This is a maintenance release, largely intended to put out improved support for new platforms and minor corrections. It should improve the speed for standalone mode, and compilation in general for some use cases, but this is mostly to clean up open ends.

Bug Fixes

  • Fix, the len built-in could give false values for dictionary and set creations with the same element.

    # This was falsely optimized to 2 even if "a is b and a == b" was true.
    len({a, b})
  • Python: Fix, the gi_running attribute of generators is no longer an int, but bool instead.

  • Python3: Fix, the int built-in with two arguments, value and base, raised UnicodeDecodeError instead of ValueError for illegal bytes given as value.

  • Python3: Using to read source code, instead of reading manually and decoding from tokenize.detect_encoding, this handles corner cases more compatible.

  • Fix, the PyLint warnings plug-in could crash in some cases, make sure it’s more robust.

  • Windows: Fix, the combination of Anaconda Python, MinGW 64 bits and mere acceleration was not working.

  • Standalone: Preserve not only namespace packages created by .pth files, but also make the imports done by them. This makes it more compatible with uses of it in Fedora 22.

  • Standalone: The extension modules could be duplicated, turned this into an error and cache finding them during compile time and during early import resolution to avoid duplication.

  • Standalone: Handle “not found” from ldd output, on some systems not all the libraries wanted are accessible for every library.

  • Python3.5: Fixed support for namespace packages, these were not yet working for that version yet.

  • Python3.5: Fixes lack of support for unpacking in normal tuple, list, and set creations.

    [*a]  # this has become legal in 3.5 and now works too.

    Now also gives compatible SyntaxError for earlier versions. Python2 was good already.

  • Python3.5: Fix, need to reduce compiled functions to __qualname__ value, rather than just __name__ or else pickling methods doesn’t work.

  • Python3.5: Fix, added gi_yieldfrom attribute to generator objects.

  • Windows: Fixed harmless warnings for Visual Studio 2015 in --debug mode.


  • Re-formulate exec and eval to default to globals() as the default for the locals dictionary in modules.

  • The try node was making a description of nodes moved to the outside when shrinking its scope, which was using a lot of time, just to not be output, now these can be postponed.

  • Refactored how freezing of bytecode works. Uncompiled modules are now explicit nodes too, and in the registry. We only have one or the other of it, avoiding to compile both.


  • When strace or dtruss are not found, given proper error message, so people know what to do.

  • The doc tests extracted and then generated for CPython3 test suites were not printing the expressions of the doc test, leading to largely decreased test coverage here.

  • The CPython 3.4 test suite is now also using common runner code, and avoids ignoring all Nuitka warnings, instead more white listing was added.

  • Started to run CPython 3.5 test suite almost completely, but coroutines are blocking some parts of that, so these tests that use this feature are currently skipped.

  • Removed more CPython tests that access the network and are generally useless to testing Nuitka.

  • When comparing outputs, normalize typical temporary file names used on posix systems.

  • Coverage tests have made some progress, and some changes were made due to its results.

  • Added test to cover too complex code module of idna module.

  • Added Python3.5 only test for unpacking variants.


  • Prepare plug-in interface to allow suppression of import warnings to access the node doing it, making the import node is accessible.

  • Have dedicated class function body object, which is a specialization of the function body node base class. This allowed removing class specific code from that class.

  • The use of “win_target” as a scons parameter was useless. Make more consistent use of it as a flag indicator in the scons file.

  • Compiled types were mixing uses of compiled_ prefixes, something with a space, sometimes with an underscore.


  • Improved support for Python3.5 missing compatibility with new language features.

  • Updated the Developer Manual with changes that SSA is now a fact.

  • Added Python3.5 Windows MSI downloads.

  • Added repository for Ubuntu Wily (15.10) for download. Removed Ubuntu Utopic package download, no longer supported by Ubuntu.

  • Added repository with RPM packages for Fedora 22.


So this release is mostly to lower the technical debt incurred that holds it back from supporting making more interesting changes. Upcoming releases may have continue that trend for some time.

This release is mostly about catching up with Python3.5, to make sure we did not miss anything important. The new function body variants will make it easier to implement coroutines, and help with optimization and compatibility problems that remain for Python3 classes.

Ultimately it will be nice to require a lot less checks for when function in-line is going to be acceptable. Also code generation will need a continued push to use the new structure in preparation for making type specific code generation a reality.

Nuitka Release 0.5.15

This release enables SSA based optimization, the huge leap, not so much in terms of actual performance increase, but for now making the things possible that will allow it.

This has been in the making literally for years. Over and over, there was just “one more thing” needed. But now it’s there.

The release includes much stuff, and there is a perspective on the open tasks in the summary, but first out to the many details.

Bug Fixes

  • Standalone: Added implicit import for reportlab package configuration dynamic import. Fixed in already.

  • Standalone: Fix, compilation of the ctypes module could happen for some import patterns, and then prevented the distribution to contain all necessary libraries. Now it is made sure to not include compiled and frozen form both. Fixed in already.

  • Fix, compilation for conditional statements where the boolean check on the condition cannot raise, could fail compilation. Fixed in already.

  • Fix, the __import__ built-in was making static optimization assuming compile time constants to be strings, which in the error case they are not, which was crashing the compiler.

    __import__(("some.module",))  # tuples don't work

    This error became only apparent, because now in some cases, Nuitka forward propagates values.

  • Windows: Fix, when installing Python2 only for the user, the detection of it via registry failed as it was only searching system key. This was a github pull request. Fixed in already.

  • Some modules have extremely complex expressions requiring too deep recursion to work on all platforms. These modules are now included entirely as bytecode fallback.

  • The standard library may contain broken code due to installation mistakes. We have to ignore their SyntaxError.

  • Fix, pickling compiled methods was failing with the wrong kind of error, because they should not implement __reduce__, but only __deepcopy__.

  • Fix, when running under wine, the check for scons binary was fooled by existence of /usr/bin/scons.

New Features

  • Added experimental support for Python3.5, coroutines don’t work yet, but it works perfectly as a 3.4 replacement.

  • Added experimental Nuitka plug-in framework, and use it for the packaging of Qt plugins in standalone mode. The API is not yet stable nor polished.

  • New option --debugger that makes --run execute directly in gdb and gives a stack trace on crash.

  • New option --profile executes compiled binary and outputs measured performance with vmprof. This is work in progress and not functional yet.

  • Started work on --internal-graph to render the SSA state into diagrams. This is work in progress and not too functional yet.

  • Plug-in framework added. Not yet ready for users. Working PyQt4 and PyQt5 plug-in support. Experimental Windows multiprocessing support. Experimental PyLint warnings disable support. More to come.

  • Added support for Anaconda accelerated mode on macOS by modifying the rpath to the Python DLL.

  • Added experimental support for multiprocessing on Windows, which needs monkey patching of the module to support compiled methods.


  • The SSA analysis is now enabled by default, eliminating variables that are not shared, and can be forward propagated. This is currently limited mostly to compile time constants, but things won’t remain that way.

  • Code generation for many constructs now takes into account if a specific operation can raise or not. If e.g. an attribute look-up is known to not raise, then that is now decided by the node the looked is done to, and then more often can determine this, or even directly the value.

  • Calls to C-API that we know cannot raise, no longer check, but merely assert the result.

  • For attribute look-up and other operations that might be known to not raise, we now only assert that it succeeds.

  • Built-in loop-ups cannot fail, merely assert that.

  • Creation of built-in exceptions never raises, merely assert that too.

  • More Python operation slots now have their own computations and some of these gained overloads for more compile time constant optimization.

  • When taking an iterator cannot raise, this is now detected more often.

  • The try/finally construct is now represented by duplicating the final block into all kinds of handlers (break, continue, return, or except) and optimized separately. This allows for SSA to trace values more correctly.

  • The hash built-in now has dedicated node and code generation too. This is mostly intended to represent the side effects of dictionary look-up, but gives more compact and faster code too.

  • Type type built-in cannot raise and has no side effect.

  • Speed improvement for in-place float operations for += and *=, as these will be common cases.


  • Made the construct based testing executable with Python3.

  • Removed warnings using the new PyLint warnings plug-in for the reflected test. Nuitka now uses the PyLint annotations to not warn. Also do not go into PyQt for reflected test, not needed. Many Python3 improvements for cases where there are differences to report.

  • The optimization tests no longer use 2to3 anymore, made the tests portable to all versions.

  • Checked more in-place operations for speed.


  • Many improvements to the coverage taking. We can hope to see public data from this, some improvements were triggered from this already, but full runs of the test suite with coverage data collection are yet to be done.


The release includes many important new directions. Coverage analysis will be important to remain certain of test coverage of Nuitka itself. This is mostly done, but needs more work to complete.

Then the graphing surely will help us to debug and understand code examples. So instead of tracing, and reading stuff, we should visualize things, to more clearly see, how things evolve under optimization iteration, and where exactly one thing goes wrong. This will be improved as it proves necessary to do just that. So far, this has been rare. Expect this to become end user capable with time. If only to allow you to understand why Nuitka won’t optimize code of yours, and what change of Nuitka it will need to improve.

The comparative performance benchmarking is clearly the most important thing to have for users. It deserves to be the top priority. Thanks to the PyPy tool vmprof, we may already be there on the data taking side, but the presenting and correlation part, is still open and a fair bit of work. It will be most important to empower users to make competent performance bug reports, now that Nuitka enters the phase, where these things matter.

As this is a lot of ground to cover. More than ever. We can make this compiler, but only if you help, it will arrive in your life time.

Nuitka Release 0.5.14

This release is an intermediate step towards value propagation, which is not considered ready for stable release yet. The major point is the elimination of the try/finally expressions, as they are problems to SSA. The try/finally statement change is delayed.

There are also a lot of bug fixes, and enhancements to code generation, as well as major cleanups of code base.

Bug Fixes

  • Python3: Added support assignments trailing star assignment.

    *a, b = 1, 2

    This raised ValueError before.

  • Python3: Properly detect illegal double star assignments.

    *a, *b = c
  • Python3: Properly detect the syntax error to star assign from non-tuple/list.

    *a = 1
  • Python3.4: Fixed a crash of the binary when copying dictionaries with split tables received as star arguments.

  • Python3: Fixed reference loss, when using raise a from b where b was an exception instance. Fixed in already.

  • Windows: Fix, the flag --disable-windows-console was not properly handled for MinGW32 run time resulting in a crash.

  • Python2.7.10: Was not recognizing this as a 2.7.x variant and therefore not applying minor version compatibility levels properly.

  • Fix, when choosing to have frozen source references, code objects were not use the same value as __file__ did for its filename.

  • Fix, when re-executing itself to drop the site module, make sure we find the same file again, and not according to the PYTHONPATH changes coming from it. Fixed in already.

  • Enhanced code generation for del variable statements, where it’s clear that the value must be assigned.

  • When pressing CTRL-C, the stack traces from both Nuitka and Scons were given, we now avoid the one from Scons.

  • Fix, the dump from --xml no longer contains functions that have become unused during analysis.

  • Standalone: Creating or running programs from inside unicode paths was not working on Windows. Fixed in already.

  • Namespace package support was not yet complete, importing the parent of a package was still failing. Fixed in already.

  • Python2.6: Compatibility for exception check messages enhanced with newest minor releases.

  • Compatibility: The NameError in classes needs to say global name and not just name too.

  • Python3: Fixed creation of XML representation, now done without lxml as it doesn’t support needed features on that version. Fixed in already.

  • Python2: Fix, when creating code for the largest negative constant to still fit into int, that was only working in the main module. Fixed in already.

  • Compatibility: The print statement raised an assertion on unicode objects that could not be encoded with ascii codec.

New Features

  • Added support for Windows 10.

  • Followed changes for Python 3.5 beta 2. Still only usable as a Python 3.4 replacement, no new features.

  • Using a self compiled Python running from the source tree is now supported.

  • Added support for Anaconda Python distribution. As it doesn’t install the Python DLL, we copy it along for acceleration mode.

  • Added support for Visual Studio 2015. Fixed in already.

  • Added support for self compiled Python versions running from build tree, this is intended to help debug things on Windows.


  • Function in-lining is now present in the code, but still disabled, because it needs more changes in other areas, before we can generally do it.

  • Trivial outlines, result of re-formulations or function in-lining, are now in-lined, in case they just return an expression.

  • The re-formulation for or and and has been giving up, eliminating the use of a try/finally expression, at the cost of dedicated boolean nodes and code generation for these.

    This saves around 8% of compile time memory for Nuitka, and allows for faster and more complete optimization, and gets rid of a complicated structure for analysis.

  • When a frame is used in an exception, its locals are detached. This was done more often than necessary and even for frames that are not necessary our own ones. This will speed up some exception cases.

  • When the default arguments, or the keyword default arguments (Python3) or the annotations (Python3) were raising an exception, the function definition is now replaced with the exception, saving a code generation. This happens frequently with Python2/Python3 compatible code guarded by version checks.

  • The SSA analysis for loops now properly traces “break” statement situations and merges the post-loop situation from all of them. This significantly allows for and improves optimization of code following the loop.

  • The SSA analysis of try/finally statements has been greatly enhanced. The handler for finally is now optimized for exception raise and no exception raise individually, as well as for break, continue and return in the tried code. The SSA analysis for after the statement is now the result of merging these different cases, should they not abort.

  • The code generation for del statements is now taking advantage should there be definite knowledge of previous value. This speed them up slightly.

  • The SSA analysis of del statements now properly decided if the statement can raise or not, allowing for more optimization.

  • For list contractions, the re-formulation was enhanced using the new outline construct instead of a pseudo function, leading to better analysis and code generation.

  • Comparison chains are now re-formulated into outlines too, allowing for better analysis of them.

  • Exceptions raised in function creations, e.g. in default values, are now propagated, eliminating the function’s code. This happens most often with Python2/Python3 in branches. On the other hand, function creations that cannot are also annotated now.

  • Closure variables that become unreferenced outside of the function become normal variables leading to better tracing and code generation for them.

  • Function creations cannot raise except their defaults, keyword defaults or annotations do.

  • Built-in references can now be converted to strings at compile time, e.g. when printed.


  • Removed gitorious mirror of the git repository, they shut down.

  • Make it more clear in the documentation that Python2 is needed at compile time to create Python3 executables.


  • Moved more parts of code generation to their own modules, and used registry for code generation for more expression kinds.

  • Unified try/except and try/finally into a single construct that handles both through try/except/break/continue/return semantics. Finally is now solved via duplicating the handler into cases necessary.

    No longer are nodes annotated with information if they need to publish the exception or not, this is now all done with the dedicated nodes.

  • The try/finally expressions have been replaced with outline function bodies, that instead of side effect statements, are more like functions with return values, allowing for easier analysis and dedicated code generation of much lower complexity.

  • No more “tolerant” flag for release nodes, we now decide this fully based on SSA information.

  • Added helper for assertions that code flow does not reach certain positions, e.g. a function must return or raise, aborting statements do not continue and so on.

  • To keep cloning of code parts as simple as possible, the limited use of makeCloneAt has been changed to a new makeClone which produces identical copies, which is what we always do. And a generic cloning based on “details” has been added, requiring to make constructor arguments and details complete and consistent.

  • The re-formulation code helpers have been improved to be more convenient at creating nodes.

  • The old nuitka.codegen module Generator was still used for many things. These now all got moved to appropriate code generation modules, and their users got updated, also moving some code generator functions in the process.

  • The module nuitka.codegen.CodeTemplates got replaces with direct uses of the proper topic module from nuitka.codegen.templates, with some more added, and their names harmonized to be more easily recognizable.

  • Added more assertions to the generated code, to aid bug finding.

  • The auto-format now sorts pylint markups for increased consistency.

  • Releases no longer have a tolerant flag, this was not needed anymore as we use SSA.

  • Handle CTRL-C in scons code preventing per job messages that are not helpful and avoid tracebacks from scons, also remove more unused tools like rpm from out in-line copy.


  • Added the CPython3.4 test suite.

  • The CPython3.2, CPython3.3, and CPython3.4 test suite now run with Python2 giving the same errors. Previously there were a few specific errors, some with line numbers, some with different SyntaxError be raised, due to different order of checks.

    This increases the coverage of the exception raising tests somewhat.

  • Also the CPython3.x test suites now all pass with debug Python, as does the CPython 2.6 test suite with 2.6 now.

  • Added tests to cover all forms of unpacking assignments supported in Python3, to be sure there are no other errors unknown to us.

  • Started to document the reference count tests, and to make it more robust against SSA optimization. This will take some time and is work in progress.

  • Made the compile library test robust against modules that raise a syntax error, checking that Nuitka does the same.

  • Refined more tests to be directly executable with Python3, this is an ongoing effort.


This release is clearly major. It represents a huge step forward for Nuitka as it improves nearly every aspect of code generation and analysis. Removing the try/finally expression nodes proved to be necessary in order to even have the correct SSA in their cases. Very important optimization was blocked by it.

Going forward, the try/finally statements will be removed and dead variable elimination will happen, which then will give function inlining. This is expected to happen in one of the next releases.

This release is a consolidation of 8 hotfix releases, and many refactorings needed towards the next big step, which might also break things, and for that reason is going to get its own release cycle.

Nuitka Release 0.5.13

This release contains the first use of SSA for value propagation and massive amounts of bug fixes and optimization. Some of the bugs that were delivered as hotfixes, were only revealed when doing the value propagation as they still could apply to real code.

Bug Fixes

  • Fix, relative imports in packages were not working with absolute imports enabled via future flags. Fixed in already.

  • Loops were not properly degrading knowledge from inside the loop at loop exit, and therefore this could have lead missing checks and releases in code generation for cases, for del statements in the loop body. Fixed in already.

  • The or and and re-formulation could trigger false assertions, due to early releases for compatibility. Fixed in already.

  • Fix, optimizion of calls of constant objects (always an exception), crashed the compiler.Fixed in already.

  • Standalone: Added support for installations with a leading def or class statement, which is defeating our attempt to patch __file__ for it.

  • Compatibility: In full compatibility mode, the tracebacks of or and and expressions are now as wrong as they are in CPython. Does not apply to --improved mode.

  • Standalone: Added missing dependency on QtGui by QtWidgets for PyQt5.

  • macOS: Improved parsing of otool output to avoid duplicate entries, which can also be entirely wrong in the case of Qt plugins at least.

  • Avoid relative paths for main program with file reference mode original, as it otherwise changes as the file moves.

  • MinGW: The created modules depended on MinGW to be in PATH for their usage. This is no longer necessary, as we now link these libraries statically for modules too.

  • Windows: For modules, the option --run to immediately load the modules had been broken for a while.

  • Standalone: Ignore Windows DLLs that were attempted to be loaded, but then failed to load. This happens e.g. when both PySide and PyQt are installed, and could cause the dreaded conflicting DLLs message. The DLL loaded in error is now ignored, which avoids this.

  • MinGW: The resource file used might be empty, in which case it doesn’t get created, avoiding an error due to that.

  • MinGW: Modules can now be created again. The run time relative code uses an API that is WinXP only, and MinGW failed to find it without guidance.


  • Make direct calls out of called function creations. Initially this applies to lambda functions only, but it’s expected to become common place in coming releases. This is now 20x faster than CPython.

    # Nuitka avoids creating a function object, parsing function arguments:
    (lambda x: x)(something)
  • Propagate assignments from non-mutable constants forward based on SSA information. This is the first step of using SSA for real compile time optimization.

  • Specialized the creation of call nodes at creation, avoiding to have all kinds be the most flexible form (keyword and plain arguments), but instead only what kind of call they really are. This saves lots of memory, and makes the tree faster to visit.

  • Added support for optimizing the slice built-in with compile time constant arguments to constants. The re-formulation for slices in Python3 uses these a lot. And the lack of this optimization prevented a bunch of optimization in this area. For Python2 the built-in is optimized too, but not as important probably.

  • Added support for optimizing isinstance calls with compile time constant arguments. This avoids static exception raises in the exec re-formulation which tests for file type, and then optimization couldn’t tell that a str is not a file instance. Now it can.

  • Lower in-place operations on immutable types to normal operations. This will allow to compile time compute these more accurately.

  • The re-formulation of loops puts the loop condition as a conditional statement with break. The not that needs to apply was only added in later optimization, leading to unnecessary compile time efforts.

  • Removed per variable trace visit from optimization, removing useless code and compile time overhead. We are going to optimize things by making decision in assignment and reference nodes based on forward looking statements using the last trace collection.

New Features

  • Added experimental support for Python 3.5, which seems to be passing the test suites just fine. The new @ matrix multiplicator operators are not yet supported though.

  • Added support for patching source on the fly. This is used to work around a (now fixed) issue with numexpr.cpuinfo making type checks with the is operation, about the only thing we cannot detect.


  • Added repository for Ubuntu Vivid (15.04) for download. Removed Ubuntu Saucy and Ubuntu Raring package downloads, these are no longer supported by Ubuntu.

  • Added repository for Debian Stretch, after Jessie release.

  • Make it more clear in the documentation that in order to compile Python3, a Python2 is needed to execute Scons, but that the end result is a Python3 binary.

  • The PyLint checker tool now can operate on directories given on the command line, and whitelists an error that is Windows only.


  • Split up standalone code further, moving depends.exe handling to a separate module.

  • Reduced code complexity of scons interface.

  • Cleaned up where trace collection is being done. It was partially still done inside the collection itself instead in the owner.

  • In case of conflicting DLLs for standalone mode, these are now output with nicer formatting, that makes it easy to recognize what is going on.

  • Moved code to fetch depends.exe to dedicated module, so it’s not as much in the way of standalone code.


  • Made BuiltinsTest directly executable with Python3.

  • Added construct test to demonstrate the speed up of direct lambda calls.

  • The deletion of @test for the CPython test suite is more robust now, esp. on Windows, the symbolic links are now handled.

  • Added test to cover or usage with in-place assignment.

  • Cover local relative import from . with absolute_import future flag enabled.

  • Again, more basic tests are now directly executable with Python3.


This release is major due to amount of ground covered. The reduction in memory usage of Nuitka itself (the C++ compiler will still use much memory) is very massive and an important aspect of scalability too.

Then the SSA changes are truly the first sign of major improvements to come. In their current form, without eliminating dead assignments, the full advantage is not taken yet, but the next releases will do this, and that’s a major milestone to Nuitka.

The other optimization mostly stem from looking at things closer, and trying to work towards function in-lining, for which we are making a lot of progress now.

Nuitka Release 0.5.12

This release contains massive amounts of corrections for long standing issues in the import recursion mechanism, as well as for standalone issues now visible after the __file__ and __path__ values have changed to become run time dependent values.

Bug Fixes

  • Fix, the __path__ attribute for packages was still the original filename’s directory, even in file reference mode was runtime.

  • The use of runtime as default file reference mode for executables, even if not in standalone mode, was making acceleration harder than necessary. Changed to original for that case. Fixed in already.

  • The constant value for the smallest int that is not yet a long is created using 1 due to C compiler limitations, but 1 was not yet initialized properly, if this was a global constant, i.e. used in multiple modules. Fixed in already.

  • Standalone: Recent fixes around __path__ revealed issues with PyWin32, where modules from were not properly recursed to. Fixed in already.

  • The importing of modules with the same name as a built-in module inside a package falsely assumed these were the built-ins which need not exist, and then didn’t recurse into them. This affected standalone mode the most, as the module was then missing entirely.

    # Inside "x.y" module:
    import x.y.exceptions
  • Similarly, the importing of modules with the same name as standard library modules could go wrong.

    # Inside "x.y" module:
    import x.y.types
  • Importing modules on Windows and macOS was not properly checking the checking the case, making it associate wrong modules from files with mismatching case.

  • Standalone: Importing with from __future__ import absolute_import would prefer relative imports still.

  • Python3: Code generation for try/return expr/finally could loose exceptions when expr raised an exception, leading to a RuntimeError for NULL return value. The real exception was lost.

  • Lambda expressions that were directly called with star arguments caused the compiler to crash.

    (lambda *args: args)(*args)  # was crashing Nuitka


  • Focusing on compile time memory usage, cyclic dependencies of trace merges that prevented them from being released, even when replaced were removed.

  • More memory efficient updating of global SSA traces, reducing memory usage during optimization by ca. 50%.

  • Code paths that cannot and therefore must not happen are now more clearly indicated to the backend compiler, allowing for slightly better code to be generated by it, as it can tell that certain code flows need not be merged.

New Features

  • Standalone: On systems, where .pth files inject Python packages at launch, these are now detected, and taking into account. Previously Nuitka did not recognize them, due to lack of files. These are mostly pip installations of e.g. zope.interface.

  • Added option --explain-imports to debug the import resolution code of Nuitka.

  • Added options --show-memory to display the amount of memory used in total and how it’s spread across the different node types during compilation.

  • The option --trace-execution now also covers early program initialisation before any Python code runs, to ease finding bugs in this domain as well.


  • Changed default for file reference mode to original unless standalone or module mode are used. For mere acceleration, breaking the reading of data files from __file__ is useless.

  • Added check that the in-line copy of scons is not run with Python3, which is not supported. Nuitka works fine with Python3, but a Python2 is required to execute scons.

  • Discover more kinds of Python2 installations on Linux/macOS installations.

  • Added instructions for macOS to the download page.


  • Moved oset and odict modules which provide ordered sets and dictionaries into a new package nuitka.container to clean up the top level scope.

  • Moved SyntaxErrors to nuitka.tree package, where it is used to format error messages.

  • Moved nuitka.Utils package to nuitka.utils.Utils creating a whole package for utils, so as to better structure them for their purpose.


This release is a major maintenance release. Support for namespace modules injected by *.pth is a major step for new compatibility. The import logic improvements expand the ability of standalone mode widely. Many more use cases will now work out of the box, and less errors will be found on case insensitive systems.

There is aside of memory issues, no new optimization though as many of these improvements could not be delivered as hotfixes (too invasive code changes), and should be out to the users as a stable release. Real optimization changes have been postponed to be next release.

Nuitka Release 0.5.11

The last release represented a significant change and introduced a few regressions, which got addressed with hot fix releases. But it also had a focus on cleaning up open optimization issues that were postponed in the last release.

New Features

  • The filenames of source files as found in the __file__ attribute are now made relative for all modes, not just standalone mode.

    This makes it possible to put data files along side compiled modules in a deployment.

Bug Fixes

  • Local functions that reference themselves were not released. They now are.

    def someFunction():
        def f():
            f()  # referencing 'f' in 'f' caused the garbage collection to fail.

    Recent changes to code generation attached closure variable values to the function object, so now they can be properly visited. Fixed in already.

  • Python2.6: The complex constants with real or imaginary parts -0.0 were collapsed with constants of value 0.0. This became more evident after we started to optimize the complex built-in. Fixed in already.

    complex(0.0, 0.0)
    complex(-0.0, -0.0)  # Could be confused with the above.
  • Complex call helpers could leak references to their arguments. This was a regression. Fixed in already.

  • Parameter variables offered as closure variables were not properly released, only the cell object was, but not the value. This was a regression. Fixed in already.

  • Compatibility: The exception type given when accessing local variable values not initialized in a closure taking function, needs to be NameError and UnboundLocalError for accesses in the providing function. Fixed in already.

  • Fix support for “venv” on systems, where the system Python uses symbolic links too. This is the case on at least on Mageia Linux. Fixed in already.

  • Python3.4: On systems where long and Py_ssize_t are different (e.g. Win64) iterators could be corrupted if used by uncompiled Python code. Fixed in already.

  • Fix, generator objects didn’t release weak references to them properly. Fixed in already.

  • Compatibility: The __closure__ attributes of functions was so far not supported, and rarely missing. Recent changes made it easy to expose, so now it was added.

  • macOS: A linker warning about deprecated linker option -s was solved by removing the option.

  • Compatibility: Nuitka was enforcing that the __doc__ attribute to be a string object, and gave a misleading error message. This check must not be done though, __doc__ can be any type in Python.


  • Variables that need not be shared, because the uses in closure taking functions were eliminated, no longer use cell objects.

  • The try/except and try/finally statements now both have actual merging for SSA, allowing for better optimization of code behind it.

    def f():
            a = something()
            return 2
        # Since the above exception handling cannot continue the code flow,
        # we do not have to invalidate the trace of "a", and e.g. do not have
        # to generate code to check if it's assigned.
        return a

    Since try/finally is used in almost all re-formulations of complex Python constructs this is improving SSA application widely. The uses of try/except in user code will no longer degrade optimization and code generation efficiency as much as they did.

  • The try/except statement now reduces the scope of tried block if possible. When no statement raised, already the handling was removed, but leading and trailing statements that cannot raise, were not considered.

    def f():
            b = 1
            a = something()
            c = 1
            return 2

    This is now optimized to.

    def f():
        b = 1
            a = something()
            return 2
        c = 1

    The impact may on execution speed may be marginal, but it is definitely going to improve the branch merging to be added later. Note that c can only be optimized, because the exception handler is aborting, otherwise it would change behaviour.

  • The creation of code objects for standalone mode and now all code objects was creating a distinct filename object for every function in a module, despite them being same content. This was wasteful for module loading. Now it’s done only once.

    Also, when having multiple modules, the code to build the run time filename used for code objects, was calling import logic, and doing lookups to find os.path.join again and again. These are now cached, speeding up the use of many modules as well.


  • Nuitka used to have “variable usage profiles” and still used them to decide if a global variable is written to, in which case, it stays away from doing optimization of it to built-in lookups, and later calls.

    The have been replaced by “global variable traces”, which collect the traces to a variable across all modules and functions. While this is now only a replacement, and getting rid of old code, and basing on SSA, later it will also allow to become more correct and more optimized.

  • The standalone now queries its hidden dependencies from a plugin framework, which will become an interface to Nuitka internals in the future.


  • The use of deep hashing of constants allows us to check if constants become mutated during the run-time of a program. This allows to discover corruption should we encounter it.

  • The tests of CPython are now also run with Python in debug mode, but only on Linux, enhancing reference leak coverage.

  • The CPython test parts which had been disabled due to reference cycles involving compiled functions, or usage of __closure__ attribute, were reactivated.


  • Since Google Code has shutdown, it has been removed from the Nuitka git mirrors.


This release brings exciting new optimization with the focus on the try constructs, now being done more optimal. It is also a maintenance release, bringing out compatibility improvements, and important bug fixes, and important usability features for the deployment of modules and packages, that further expand the use cases of Nuitka.

The git flow had to be applied this time to get out fixes for regression bug fixes, that the big change of the last release brought, so this is also to consolidate these and the other corrections into a full release before making more invasive changes.

The cleanups are leading the way to expanded SSA applied to global variable and shared variable values as well. Already the built-in detect is now based on global SSA information, which was an important step ahead.

Nuitka Release 0.5.10

This release has a focus on code generation optimization. Doing major changes away from “C++-ish” code to “C-ish” code, many constructs are now faster or got looked at and optimized.

Bug Fixes

  • Compatibility: The variable name in locals for the iterator provided to the generator expression should be .0, now it is.

  • Generators could leak frames until program exit, these are now properly freed immediately.


  • Faster exception save and restore functions that might be in-lined by the backend C compiler.

  • Faster error checks for many operations, where these errors are expected, e.g. instance attribute lookups.

  • Do not create traceback and locals dictionary for frame when StopIteration or GeneratorExit are raised. These tracebacks were wasted, as they were immediately released afterwards.

  • Closure variables to functions and parameters of generator functions are now attached to the function and generator objects.

  • The creation of functions with closure taking was accelerated.

  • The creation and destruction of generator objects was accelerated.

  • The re-formulation for in-place assignments got simplified and got faster doing so.

  • In-place operations of str were always copying the string, even if was not necessary.

    a += b  # Was not re-using the storage of "a" in case of strings
  • Python2: Additions of int for Python2 are now even faster.

  • Access to local variable values got slightly accelerated at the expense of closure variables.

  • Added support for optimizing the complex built-in.

  • Removing unused temporary and local variables as a result of optimization, these previously still allocated storage.


  • The use of C++ classes for variable objects was removed. Closure variables are now attached as PyCellObject to the function objects owning them.

  • The use of C++ context classes for closure taking and generator parameters has been replaced with attaching values directly to functions and generator objects.

  • The indentation of code template instantiations spanning multiple was not in all cases proper. We were using emission objects that handle it new lines in code and mere list objects, that don’t handle them in mixed forms. Now only the emission objects are used.

  • Some templates with C++ helper functions that had no variables got changed to be properly formatted templates.

  • The internal API for handling of exceptions is now more consistent and used more efficiently.

  • The printing helpers got cleaned up and moved to static code, removing any need for forward declaration.

  • The use of INCREASE_REFCOUNT_X was removed, it got replaced with proper Py_XINCREF usages. The function was once required before “C-ish” lifted the need to do everything in one function call.

  • The use of INCREASE_REFCOUNT got reduced. See above for why that is any good. The idea is that Py_INCREF must be good enough, and that we want to avoid the C function it was, even if in-lined.

  • The assertObject function that checks if an object is not NULL and has positive reference count, i.e. is sane, got turned into a preprocessor macro.

  • Deep hashes of constant values created in --debug mode, which cover also mutable values, and attempt to depend on actual content. These are checked at program exit for corruption. This may help uncover bugs.


  • Speedcenter has been enhanced with better graphing and has more benchmarks now. More work will be needed to make it useful.

  • Updates to the Developer Manual, reflecting the current near finished state of “C-ish” code generation.


  • New reference count tests to cover generator expressions and their usage got added.

  • Many new construct based tests got added, these will be used for performance graphing, and serve as micro benchmarks now.

  • Again, more basic tests are directly executable with Python3.


This is the next evolution of “C-ish” coming to pass. The use of C++ has for all practical purposes vanished. It will remain an ongoing activity to clear that up and become real C. The C++ classes were a huge road block to many things, that now will become simpler. One example of these were in-place operations, which now can be dealt with easily.

Also, lots of polishing and tweaking was done while adding construct benchmarks that were made to check the impact of these changes. Here, generators probably stand out the most, as some of the missed optimization got revealed and then addressed.

Their speed increases will be visible to some programs that depend a lot on generators.

This release is clearly major in that the most important issues got addressed, future releases will provide more tuning and completeness, but structurally the “C-ish” migration has succeeded, and now we can reap the benefits in the coming releases. More work will be needed for all in-place operations to be accelerated.

More work will be needed to complete this, but it’s good that this is coming to an end, so we can focus on SSA based optimization for the major gains to be had.

Nuitka Release 0.5.9

This release is mostly a maintenance release, bringing out minor compatibility improvements, and some standalone improvements. Also new options to control the recursion into modules are added.

Bug Fixes

  • Compatibility: Checks for iterators were using PyIter_Check which is buggy when running outside of Python core, because it’s comparing pointers we don’t see. Replaced with HAS_ITERNEXT helper which compares against the pointer as extracting for a real non-iterator object.

    class Iterable:
        def __init__(self):
            self.consumed = 2
        def __iter__(self):
            return Iterable()
    iter(Iterable())  # This is suppose to raise, but didn't with Nuitka
  • Python3: Errors when creating class dictionaries raised by the __prepare__ dictionary (e.g. enum classes with wrong identifiers) were not immediately raised, but only by the type call.

    This was not observable, but might have caused issues potentially.

  • Standalone macOS: Shared libraries and extension modules didn’t have their DLL load paths updated, but only the main binary. This is not sufficient for more complex programs.

  • Standalone Linux: Shared libraries copied into the .dist folder were read-only and executing chrpath could potentially then fail. This has not been observed, but is a conclusion of macOS fix.

  • Standalone: When freezing standard library, the path of Nuitka and the current directory remained in the search path, which could lead to looking at the wrong files.


  • The getattr built-in is now optimized for compile time constants if possible, even in the presence of a default argument. This is more a cleanup than actually useful yet.

  • The calling of PyCFunction from normal Python extension modules got accelerated, especially for the no or single argument cases where Nuitka now avoids building the tuple.

New Features

  • Added the option --recurse-pattern to include modules per filename, which for Python3 is the only way to not have them in a package automatically.

  • Added the option --generate-c++-only to only generate the C++ source code without starting the compiler.

    Mostly used for debugging and testing coverage. In the later case we do not want the C++ compiler to create any binary, but only to measure what would have been used.


  • Renamed the debug option --c++-only to --recompile-c++-only to make its purpose more clear and there now is --generate-c++-only too.


  • Added support for taking coverage of Nuitka in a test run on a given input file.

  • Added support for taking coverage for all Nuitka test runners, migrating them all to common code for searching.

  • Added uniform way of reporting skipped tests, not generally used yet.


This release marks progress towards having coverage testing. Recent releases had made it clear that not all code of Nuitka is actually used at least once in our release tests. We aim at identifying these.

Another direction was to catch cases, where Nuitka leaks exceptions or is subject to leaked exceptions, which revealed previously unnoticed errors.

Important changes have been delayed, e.g. the closure variables will not yet use C++ objects to share storage, but proper PyCellObject for improved compatibility, and to approach a more “C-ish” status. These is unfinished code that does this. And the forward propagation of values is not enabled yet again either.

So this is an interim step to get the bug fixes and improvements accumulated out. Expect more actual changes in the next releases.

Nuitka Release 0.5.8

This release has mainly a focus on cleanups and compatibility improvements. It also advances standalone support, and a few optimization improvements, but it mostly is a maintenance release, attacking long standing issues.

Bug Fixes

  • Compatibility Windows macOS: Fix importing on case insensitive systems.

    It was not always working properly, if there was both a package Something and something, by merit of hav