21 February 2022

Nuitka Release 0.7

This is to inform you about the new stable release of Nuitka. It is the extremely compatible Python compiler, “download now”.

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.