10 June 2019

Nuitka Release 0.6.4

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

This release contains many bug fixes all across the board. There is also new optimization and many organizational 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.