Changes/Python3.13

Summary

Update the Python stack in Fedora from Python 3.12 to Python 3.13, the newest major release of the Python programming language.

Owner

• Name: Miro Hrončok
• Name: Karolina Surma
• Email: python-maint@redhat.com

Current status

• Targeted release: Fedora Linux 41
• Last updated: 2024-09-17
• Announced
• Discussion thread
• FESCo issue: #3111
• Tracker bug: #2244836
• Release notes tracker: <will be assigned by the Wrangler>

Detailed Description

We would like to upgrade Python to 3.13 in Fedora 41 thus we are proposing this plan early.

See the upstream notes at What's new in 3.13.

Important dates and plan

• 2023-05-22: Python 3.13 development begins
• 2023-10-13: Python 3.13.0 alpha 1
  • Package it as python3.13 for testing purposes
  • Start the bootstrap procedure in Copr
  • Do a mass rebuild against every future release in Copr
• 2023-11-21: Python 3.13.0 alpha 2
• 2023-12-19: Python 3.13.0 alpha 3
• 2024-02-06: Branch Fedora 40, Rawhide becomes future Fedora 41
  • The earliest point when we can start rebuilding in Koji side-tag
• 2024-02-13: Python 3.13.0 alpha 4
• 2024-03-12: Python 3.13.0 alpha 5
• 2024-04-09: Python 3.13.0 alpha 6
• 2024-05-07: Python 3.13.0 beta 1
  • No new features beyond this point
• 2024-06-04: Python 3.13.0 beta 2
  • The ideal point when we can start rebuilding in Koji
• 2024-06-11: Expected side tag-merge (optimistic)
• 2024-06-25: Python 3.13.0 beta 3
• 2024-07-02: Expected side tag-merge (realistic)
• 2024-07-15: Expected side tag-merge (pessimistic)
• 2024-07-16: Python 3.13.0 beta 4
• 2024-07-17: Fedora 41 Mass Rebuild
  • The mass rebuild happens with the fourth or third beta. We might need to rebuild Python packages later in exceptional case.
  • If the Koji side-tag is not merged yet at this point, we defer the change to Fedora 42.
• 2024-07-30: Python 3.13.0 candidate 1
  • This serves as "final" for our purposes.
• 2024-08-06: Branch Fedora 41, Rawhide becomes future Fedora 42
• 2024-08-06: Fedora 41 Change Checkpoint: Completion deadline (testable)
• 2024-08-20: Fedora Beta Freeze
  • If rebuild with 3.13.0rc1 is needed, we should strive to do it before the freeze - there is a window of 3 weeks.
• 2024-09-03: Python 3.13.0 candidate 2
• 2024-09-10: Fedora 41 Beta Release (Preferred Target)
  • Beta will likely be released with 3.13.0rc1.
• 2024-09-17: Fedora 41 Beta Target date #1
• 2024-10-01: Python 3.13.0 final
• 2024-10-01: Fedora 39 Final Freeze
  • We'll update to 3.13.0 final using a freeze exception.
• 2024-10-15: Fedora 39 Preferred Final Target date
• 2024-10-22: Fedora 39 Final Target date #1

(From Python 3.13 Release Schedule and Fedora 41 Release Schedule.)

The schedule might appear somewhat tight for Fedora 41, but Python's annual release cycle was adapted for Fedora and this worked fine since Python 3.9 and Fedora 33. It is now common that Python is upgraded on a similar schedule in every odd-numbered Fedora release.

Note that upstream's "release candidates" are frozen except for blocker bugs. Since we can and will backport blocker fixes between Fedora and upstream, we essentially treat the Release Candidate as the final release.

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. Packages in Fedora can use the new features from 3.13.

There's also a benefit to the larger Python ecosystem: by building Fedora's packages against 3.13 while it's still in development, we can catch critical bugs before the final 3.13.0 release.

Scope

We will coordinate the work in a side tag and merge when ready.

• Proposal owners:
  1. Introduce python3.13 for all Fedoras
  2. Prepare stuff in Copr as explained in description.
  3. Update python-rpm-macros so python3.13 builds python3
  4. Build python3.13 as the main Python
  5. Mass rebuild all the packages that runtime require python(abi) = 3.12 and/or libpython3.12.so.1.0 (~4000 known packages in October 2023)
  6. Build python3.13 as a non-main Python

• Other developers: Maintainers of packages that fail to rebuild during the rebuilds will be asked, using e-mail and bugzilla, to fix or remove their packages from the distribution. If any issues appear, they should be solvable either by communicating with the respective upstreams first and/or applying downstream patches. Also, the package maintainers should have a look at: Porting to Python 3.13. The python-maint team will be available to help with fixing issues.

• Release engineering: #11728

• Policies and guidelines: N/A (not needed for this Change)

• Trademark approval: N/A (not needed for this Change)

• Alignment with Community Initiatives: N/A

Upgrade/compatibility impact

All the packages that depend on Python 3 must be rebuilt. User written Python 3 scripts/applications may require a small amount of porting, but mostly Python 3.12 is forward compatible with Python 3.13.

How To Test

Interested testers do not need special hardware. If you have a favourite Python 3 script, module, or application, please test it with Python 3.13 and verify that it still works as you would expect. If the application you are testing does not require any other modules, you can test it using python3.13 even before this change is implemented, in Fedora 37, 38, 39 or 40.

In case your application requires other modules, or if you are testing an rpm package, it is necessary to install the 3.13 version of the python3 rpm. Right now that rpm is available in copr, along with all other python packages that build successfully with python 3.13. See https://copr.fedorainfracloud.org/coprs/g/python/python3.13/ for detailed instructions on how to enable Python 3.13 copr for mock.

Once the change is in place, test if your favorite Python apps are working as they were before. File bugs if they don't.

User Experience

Regular distro users shouldn't notice any change in system behaviour other than the Python 3 interpreter will be in version 3.13.

Dependencies

4400+ packages depend on Python 3 and ~4000 packages need rebuilding when Python is upgraded. See scope section.

Contingency Plan

• Contingency mechanism: Do not merge the side tag with rawhide. If the side tag has been merged and issues arise, that will justify a downgrade, then use an epoch tag to revert to 3.12 version (never needed before)
• Contingency deadline: beta freeze
• Blocks release? Yes, we'd like to block Fedora 41 release on at least 3.13.0rc1

Documentation

Python 3.13 Release Schedule

What's new in 3.13

Porting to Python 3.13

Release Notes

https://gitlab.com/fedora/docs/fedora-linux-documentation/release-notes/-/issues/94