From Fedora Project Wiki

< Features

Revision as of 02:11, 5 August 2012 by Dmalcolm (talk | contribs) (Current status)

Python 3.3


Update the Python 3 stack in Fedora from 3.2 to 3.3


  • Email: <>

Current status

  • Targeted release: Fedora 18
  • Last updated: 2012-08-04
  • Percentage of completion: 80% (see detailed notes under "Scope" below and in Talk:Features/Python_3.3)
    • Done: Successful mock rebuilds of the core python3 package for Python 3.3 (with full test suite)
    • Done: 95 add-on packages successfully rebuild in mock environment
    • TODO: fix remaining 13 packages so they rebuild in mock environment
    • Done: python3.3b1 built "for real" in Koji
    • Done: 91 add-on packages successfully rebuilt in Koji
    • TODO: 16 remaining packages to be built in Koji
    • TODO: build further releases of 3.3 into Koji
    • TODO: testing

Upstream is at feature freeze for 3.3; latest tarball release is Python 3.3.0 beta 1, released on June 27th, 2012.

Month Python 3.3 release schedule) Fedora 18 Schedule Fedora 19 Schedule
March 3.3.0 alpha 1: March 3, 2012
3.3.0 alpha 2: March 31, 2012
April 3.3.0 alpha 3: April 28, 2012
May 3.3.0 alpha 4: May 26, 2012 Start Feature Submission Wed 2012-05-02
June 3.3.0 beta 1: June 23, 2012: (No new features beyond this point.)
July 3.3.0 beta 2: July 14, 2012
Feature Submission Deadline Tue 2012-07-24
3.3.0 candidate 1: July 28, 2012
Feature Freeze (Testable/Complete) Tue 2012-08-07
Branch Fedora 18 from Rawhide Tue 2012-08-07
August 2012-08-14 Alpha Change Deadline
3.3.0 candidate 2: August 11, 2012
2012-08-28 Alpha Release
3.3.0 final: August 18, 2012
September 2012-09-18 Beta Change Deadline / Features 100% Complete

Note: Fedora 18 schedule above is based on Releases/18/Schedule as 2012-07-19

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