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Python 3.3


Update the Python 3 stack in Fedora from 3.2 to 3.3


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Current status

Detailed Description

Python 3.3 adds numerous features and optimizations. See the upstream notes at and

Benefit to Fedora

Fedora aims to showcase the latest in free and open source software - we should have the most recent release of Python 3.


Compare with the Python 3.2 feature page.

We need to wait for Python 3.3 to reach feature freeze, so that the bytecode format for .pyc files is frozen, together with the ABI for extension modules.

At that point we can rebase python3 to the latest release candidate of that code. We would then need to rebuild all python 3 packages. See

For bonus points, we ought to tell "file" and "rpmlint" about the new bytecode format for .pyc files.

Note that the suffix of some files should change, and this may require slight packaging tweaks in the various packages that ship Python 3 code:

  • bytecode files changing from .cpython-32.pyc (and .cpython-32.pyo) to .cpython-33.pyc (and .cpython-32.pyo)
  • extension modules changing from to (the "u" part goes away as part of PEP 393).

There have been some C API changes (especially relating to unicode handling); if we're unlucky we may need to do some code patching to get some extension modules to compile.

Detailed notes on the extent of the rebuild and the current status can be seen in Talk:Features/Python_3.3

How To Test

Interested testers do not need special hardware. If you have a favorite Python 3 script, module, or application, please test it with Python 3.3 and verify that it still works as you expect.

My own test plan:

  • Smoketest of the interpreter
  • Run the upstream regression test suite (this is done during %check)

User Experience

Users should not notice any difference, other than the availability of the 3.3 interpreter


See notes in "Scope" above.

Contingency Plan

I'm working on test rebuilds of all affected packages, using skvidal's mockchain tool (this also gives us a build ordering, by grepping the logs).

I plan to commit any proposed changes to "python3.3" branches of dist-git, and then merge to master when we do it for real.

This pre-planning should mean everything is ready and any major issues should have been shaken out before we "pull the trigger" and commit/build for real into f18.


What's New In Python 3.3

Release Notes

The system Python 3 stack has been upgraded to 3.3 (the system Python 2 stack remains at 2.7), bringing in hundreds of fixes and tweaks; for a list of changes see

Comments and Discussion