18 October 2017

Nuitka Release 0.5.28

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

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 package.name>.

  • 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 setup.py --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 nuitka.tools.quality namespace.

  • Move output comparison tool to the nuitka.tools.testing 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.