Nuitka Release 0.5.16

This is to inform you about the new stable release of Nuitka. It is the extremely compatible Python compiler. Please see the page "What is Nuitka?" for an overview.

This is a maintenance release, largely intended to put out improved support for new platforms and minor corrections. It should improve the speed for standalone mode, and compilation in general for some use cases, but this is mostly to clean up open ends.

Bug Fixes

  • Fix, the len built-in could give false values for dictionary and set creations with the same element.

    # This was falsely optimized to 2 even if "a is b and a == b" was true.
    len({a, b})
  • Python: Fix, the gi_running attribute of generators is no longer an int, but bool instead.

  • Python3: Fix, the int built-in with two arguments, value and base, raised UnicodeDecodeError instead of ValueError for illegal bytes given as value.

  • Python3: Using to read source code, instead of reading manually and decoding from tokenize.detect_encoding, this handles corner cases more compatible.

  • Fix, the PyLint warnings plug-in could crash in some cases, make sure it's more robust.

  • Windows: Fix, the combination of AnaConda Python, MinGW 64 bits and mere acceleration was not working. Issue#254.

  • Standalone: Preserve not only namespace packages created by .pth files, but also make the imports done by them. This makes it more compatible with uses of it in Fedora 22.

  • Standalone: The extension modules could be duplicated, turned this into an error and cache finding them during compile time and during early import resolution to avoid duplication.

  • Standalone: Handle "not found" from ldd output, on some systems not all the libraries wanted are accessible for every library.

  • Python3.5: Fixed support for namespace packages, these were not yet working for that version yet.

  • Python3.5: Fixes lack of support for unpacking in normal tuple, list, and set creations.

    [*a] # this has become legal in 3.5 and now works too.

    Now also gives compatible SyntaxError for earlier versions. Python2 was good already.

  • Python3.5: Fix, need to reduce compiled functions to __qualname__ value, rather than just __name__ or else pickling methods doesn't work.

  • Python3.5: Fix, added gi_yieldfrom attribute to generator objects.

  • Windows: Fixed harmless warnings for Visual Studio 2015 in --debug mode.


  • Re-formulate exec and eval to default to globals() as the default for the locals dictionary in modules.
  • The try node was making a description of nodes moved to the outside when shrinking its scope, which was using a lot of time, just to not be output, now these can be postponed.
  • Refactored how freezing of bytecode works. Uncompiled modules are now explicit nodes too, and in the registry. We only have one or the other of it, avoiding to compile both.


  • When strace or dtruss are not found, given proper error message, so people know what to do.
  • The doc tests extracted and then generated for CPython3 test suites were not printing the expressions of the doc test, leading to largely decreased test coverage here.
  • The CPython 3.4 test suite is now also using common runner code, and avoids ignoring all Nuitka warnings, instead more white listing was added.
  • Started to run CPython 3.5 test suite almost completely, but coroutines are blocking some parts of that, so these tests that use this feature are currently skipped.
  • Removed more CPython tests that access the network and are generally useless to testing Nuitka.
  • When comparing outputs, normalize typical temporary file names used on posix systems.
  • Coverage tests have made some progress, and some changes were made due to its results.
  • Added test to cover too complex code module of idna module.
  • Added Python3.5 only test for unpacking variants.


  • Prepare plug-in interface to allow suppression of import warnings to access the node doing it, making the import node is accessible.
  • Have dedicated class function body object, which is a specialization of the function body node base class. This allowed removing class specific code from that class.
  • The use of "win_target" as a scons parameter was useless. Make more consistent use of it as a flag indicator in the scons file.
  • Compiled types were mixing uses of compiled_ prefixes, something with a space, sometimes with an underscore.


  • Improved support for Python3.5 missing compatibility with new language features.
  • Updated the Developer Manual with changes that SSA is now a fact.
  • Added Python3.5 Windows MSI downloads.
  • Added repository for Ubuntu Wily (15.10) for download. Removed Ubuntu Utopic package download, no longer supported by Ubuntu.
  • Added repository with RPM packages for Fedora 22.


So this release is mostly to lower the technical debt incurred that holds it back from supporting making more interesting changes. Upcoming releases may have continue that trend for some time.

This release is mostly about catching up with Python3.5, to make sure we did not miss anything important. The new function body variants will make it easier to implement coroutines, and help with optimization and compatibility problems that remain for Python3 classes.

Ultimately it will be nice to require a lot less checks for when function in-line is going to be acceptable. Also code generation will need a continued push to use the new structure in preparation for making type specific code generation a reality.


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