Most changes to Python require a NEWS entry. Add one using the blurb_it web app or the blurb command-line tool.

If this change has little impact on Python users, wait for a maintainer to apply the skip news label instead.

On a second thought it makes sense to add it, but in which section this change falls in?

Yes, this deserves a NEWS entry, and it should go in Library section, I think.

This not only deserves a change log entry but also a "What's New in Python 3.14" entry.

@carljm, @ambv: I've added requested entries

For the "WhatsNew in 3.14" I looked on how it was added for python 3.8 (the rst file), it includes some wording about the impact on performance (under Optimizations section):

• The default protocol in the :mod:pickle module is now Protocol 4,
  first introduced in Python 3.4. It offers better performance and smaller
  size compared to Protocol 3 available since Python 3.0.

Is it a good idea to add something like that here? Since I'm starting contributing now, I will need some help to fulfill it :)

Before bumping it to version 5, I would like to address #120380 since it could introduce breakage. At least, there was something that was not correctly handled for pickle's buffers.

Before bumping it to version 5, I would like to address #120380 since it could introduce breakage. At least, there was something that was not correctly handled for pickle's buffers.

no problem, thanks!!

Now that #120380 is fixed, I think this can be done, unless someone finds something that is broken for protocol 5 or something that should be supported for protocol 5 and that is not. There are #84895 and #89467 which could be something that is desired before bumping the default protocol to protocol 5 since they could dramatically improve performances (especially the second one).

I don't think either of those needs to block this PR.

I've resolved the conflict in the What's New document, and in the process moved the entry from Optimizations to Improved Modules. Unlike version 4, version 5 isn't primarily a performance improvement.

See also the failed CI check:

Generated files not up to date.
Perhaps you forgot to run make regen-all or build.bat --regen. ;)

See also the failed CI check:

Generated files not up to date.
Perhaps you forgot to run make regen-all or build.bat --regen. ;)

oh, cool
I run the mentioned command, should I commit the modified files them (Modules/_pickle.c and Modules/clinic/_pickle.c.h)?

Yes please!

Thank you!