Python Annual Release Cycle adjusted to match odd-numbered Fedora releases

[Miro Hrončok]

Hello,

I'd like to inform you that [PEP 602] "Annual Release Cycle for Python" has
been 
approved and [PEP 596] "Python 3.9 Release Schedule" is pending approval:

tl;dr New Python 3.X versions will be released annually, with RC period adjusted 
to make it possible to update Python in odd-numbered Fedora releases. We plan to 
submit the Python 3.9 change proposal for Fedora 33 after the first Python 3.9 
alpha (expected in ~2 weeks).


The Python 3.8 update was postponed from Fedora 31 to Fedora 32 because the 
schedule was too tight. With 3.9 and the recent adjustments, we expect that 
Fedora 33 is a reasonable target release, but we are prepared to reevaluate that 
after branching.

Like with 3.8, we plan to rebuild Fedora packages with Python 3.9 pre-releases, 
file bugs, and coordinate fixes both to Python and the software that uses it. We 
hope to make that process smoother, but even more effective at finding and 
resolving incompatibilities. With the shorter cycle, we anticipate less 
incompatibilities.


Quotes from PEP 602:

(Rationale and Goals)
"This change provides the following advantages: ... allows for synchronizing the 
schedule of Python release management with external distributors like Fedora 
who've been historically very helpful in finding regressions early not only in 
core Python but also in third-party libraries, helping moving the community 
forward to support the latest version of Python from Day 1"

(Rejected Ideas)
"While [keeping 4 betas over 4 months and a final month for the release 
candidate] would make the release calendar a bit cleaner, it would make it very 
hard for external distributors like Fedora to release the newest version of 
Python as soon as possible. We are adjusting Python's calendar here in the hope 
that this will enable Fedora to integrate the newest version of Python with the 
newest version of Fedora as both are being developed which makes both projects 
better."

Quotes from the [python-dev] mailing list:

"...in order to give the community enough time to provide feedback in the betas 
while having enough time to thoroughly test the RC and to prep for the final 
release so the delay from Python's final release to any new project releases is 
minimal. It should also fit into the release schedule of Linux distributions 
like Fedora better than previously proposed so the distributions can test the RC 
when they start preparing for their own October releases."
-- Brett Cannon, Python Steering Council member

"[2 months for RCs instead of 1] allows for synchronizing the schedule of Python 
release management with Fedora. They've been historically very helpful in early 
finding regressions not only in core Python but also in third-party libraries, 
helping moving the community forward. It seems like a bargain to make a slight 
adjustment of our schedule to help Fedora help us make 3.9 and beyond better 
releases."
-- Łukasz Langa, Python 3.8 and 3.9 Release Manager


[PEP 596] https://www.python.org/dev/peps/pep-0596/
[PEP 602] https://www.python.org/dev/peps/pep-0602/
[python-dev] 
https://mail.python.org/archives/list/[e-mail]/thread/KE7OS4...
-- 
Miro Hrončok
--
Phone: [phone]
IRC: mhroncok