Nuitka Release 0.3.18

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

This is to inform you about the new stable release of Nuitka. This time there are a few bug fixes, and the important step that triggered the release: Nuitka has entered Debian Unstable. So you if want, you will get stable Nuitka releases from now on via apt-get install nuitka.

The release cycle was too short to have much focus. It merely includes fixes, which were available as hot fixes, and some additional optimization and node tree cleanups, as well as source cleanups. But not much else.

Bug fixes

  • Conditional statements with both branches empty were not optimized away in all cases, triggering an assertion of code generation. Released as 0.3.17a hot fix already.

  • Nuitka was considering directories to contain packages that had no “__init__.py” which could lead to errors when it couldn’t find the package later in the compilation process. Released as 0.3.17a hot fix already.

  • When providing locals() to exec statements, this was not making the locals() writable. The logic to detect the case that default value is used (None) and be pessimistic about it, didn’t consider the actual value locals(). Released as 0.3.17b hot fix already.

  • Compatibility Fix: When no defaults are given, CPython uses None for func.func_defaults, but Nuitka had been using None.

Optimization

  • If the condition of assert statements can be predicted, these are now optimized in a static raise or removed.

  • For built-in name references, there is now dedicated code to look them up, that doesn’t check the module level at all. Currently these are used in only a few cases though.

  • Cleaner code is generated for the simple case of print statements. This is not only faster code, it’s also more readable.

Cleanups

  • Removed the CPythonStatementAssert node.

    It’s not needed, instead at tree building, assert statements are converted to conditional statements with the asserted condition result inverted and a raise statement with AssertionError and the assertion argument.

    This allowed to remove code and complexity from the subsequent steps of Nuitka, and enabled existing optimization to work on assert statements as well.

  • Moved built-in exception names and built-in names to a new module nuitka.Builtins instead of having in other places. This was previously a bit spread-out and misplaced.

  • Added cumulative tags to node classes for use in checks. Use it annotate which node kinds to visit in e.g. per scope finalization steps. That avoids kinds and class checks.

  • New node for built-in name lookups

    This allowed to remove tricks played with adding module variable lookups for staticmethod when adding them for __new__ or module variable lookups for str when predicting the result of type('a'), which was unlikely to cause a problem, but an important TODO item still.

Organisational

  • The “Download” page is now finally updated for releases automatically.

    Up to this release, I had to manually edit that page, but now mastered the art of upload via XMLRCP and a Python script, so that don’t loose as much time with editing, checking it, etc.

  • The Debian package is backportable to Ubuntu Natty, Maverick, Oneiric, I expect to make a separate announcement with links to packages.

  • Made sure the test runners worth with bare python2.6 as well.

New Tests

  • Added some tests intended for type inference development.

Summary

This releases contains not as much changes as others, mostly because it’s the intended base for a Debian upload.

The exec fix was detected by continued work on the branch feature/minimize_CPython26_tests_diff branch, but that work is now complete.

It is being made pretty (many git rebase iterations) with lots of Issues being added to the bug tracker and referenced for each change. The intention is to have a clean commits repository with the changed made.

But of course, the real excitement is the “type inference” work. It will give a huge boost to Nuitka. With this in place, new benchmarks may make sense. I am working on getting it off the ground, but also to make us more efficient.

So when I learn something. e.g. assert is not special, I apply it to the develop branch immediately, to keep the differences as small as possible, and to immediately benefit from such improvements.

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