25 April 2016

Nuitka Release 0.5.21

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

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.