05 December 2013

Nuitka Release 0.4.7

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

This release includes important new features, lots of polishing cleanups, and some important performance improvements as well.

Bug Fixes

  • The RPM packages didn’t build due to missing in-line copy of Scons. Fixed in already.

  • The recursion into modules and unfreezing them was not working for packages and modules anymore. Fixed in already.

  • The Windows installer was not including Scons. Fixed in already.

  • Windows: The immediate execution as performed by nuitka --execute was not preserving the exit code.

  • Python3.3: Packages without __init.py__ were not properly embedding the name-space package as well.

  • Python3: Fix, modules and packages didn’t add themselves to sys.modules which they should, happened only for programs.

  • Python3.3: Packages should set __package to their own name, not the one of their parents.

  • Python3.3: The __qualname__ of nested classes was corrected.

  • For modules that recursed to other modules, an infinite loop could be triggered when comparing types with rich comparisons.

New Features

  • The “standalone” mode allows to compile standalone binaries for programs and run them without Python installation. The DLLs loaded by extension modules on Windows need to be added manually, on Linux these are determined automatically already.

    To achieve running without Python installation, Nuitka learned to freeze bytecode as an alternative to compiling modules, as some modules need to be present when the CPython library is initialized.

  • New option --python-flag allows to specify flags to the compiler that the “python” binary normally would. So far -S and -v are supported, with sane aliases no_site and trace_imports.

    The recommended use of --python-flag=-S is to avoid dependency creep in standalone mode compilations, because the site module often imports many useless things that often don’t apply to target systems.


  • Faster frame stack handling for functions without try/except (or try/finally in Python3). This gives a speed boost to “PyStone” of ca. 2.5% overall.

  • Python2: Faster attribute getting and setting, handling special cases at compile time. This gives a minor speed boost to “PyStone” of ca. 0.5% overall.

  • Python2: Much quicker calls of __getattr__ and __setattr__ as this is now using the quicker call method avoiding temporary tuples.

  • Don’t treat variables usages used in functions called directly by their owner as shared. This leads to more efficient code generation for contractions and class bodies.

  • Create unicode constants directly from their UTF-8 string representation for Python2 as well instead of un-streaming. So far this was only done for Python3. Affects only program start-up.

  • Directly create int and long constants outside of 2**31 and 2**32-1, but only limited according to actual platform values. Affects only program start-up.

  • When creating set values, no longer use a temporary tuple value, but use a properly generated helper functions instead. This makes creating sets much faster.

  • Directly create set constants instead of un-streaming them. Affects only program start-up.

  • For correct line numbers in traceback, the current frame line number must be updated during execution. This was done more often than necessary, e.g. loops set the line number before loop entry, and at first statement.

  • Module variables are now accessed even faster, the gain for “PyStone” is only 0.1% and mostly the result of leaner code.


  • The “standalone mode” code (formerly known as “portable mode” has been redone and activated. This is a feature that a lot of people expect from a compiler naturally. And although the overall goal for Nuitka is of course acceleration, this kind of packaging is one of the areas where CPython needs improvement.

  • Added package for Ubuntu 13.10 for download, removed packages for Ubuntu 11.04 and 11.10, no more supported.

  • Added package for openSUSE 13.1 for download.

  • Nuitka is now part of Arch and can be installed with pacman -S nuitka.

  • Using dedicated Buildbot for continuous integration testing. Not yet public.

  • Windows: In order to speed up repeated compilation on a platform without ccache, added Scons level caching in the build directory.

  • Disabled hash randomization for inside Nuitka (but not in ultimately created binaries) for a more stable output, because dictionary constants will not change around. This makes the build results possible to cache for ccache and Scons as well.


  • The programs tests cases now fail if module or directory recursion is not working, being executed in another directory.

  • Added test runner for packages, with initial test case for package with recursion and sub-packages.

  • Made some test cases more strict by reducing PYTHONPATH provision.

  • Detect use of extra flags in tests that don’t get consumed avoiding ineffective flags.

  • Use --execute on Windows as well, the issue that prevented it has been solved after all.


  • The generated code uses const_, var_, par_ prefixes in the generated code and centralized the decision about these into single place.

  • Module variables no longer use C++ classes for their access, but instead accessor functions, leading to much less code generated per module variable and removing the need to trace their usage during code generation.

  • The test runners now share common code in a dedicated module, previously they replicated it all, but that turned out to be too tedious.

  • Massive general cleanups, many of which came from new contributor Juan Carlos Paco.

  • Moved standalone and freezer related codes to dedicated package nuitka.freezer to not pollute the nuitka package name space.

  • The code generation use variable identifiers and their accesses was cleaned up.

  • Removed several not-so-special case identifier classes because they now behave more identical and all work the same way, so a parameters can be used to distinguish them.

  • Moved main program, function object, set related code generation to dedicated modules.


This release marks major technological progress with the introduction of the much sought standalone mode and performance improvements from improved code generation.

The major break through for SSA optimization was not yet achieved, but this is again making progress in the direction of it. Harmonizing variables of different kinds was an important step ahead.

Also very nice is the packaging progress, Nuitka was accepted into Arch after being in Debian Testing for a while already. Hope is to see more of this kind of integration in the future.