bpo-45173: Keep configparser deprecations until Python 3.12

[hugovk]

First commit:

Revert #28292 / 1fc41ae to give projects another year to update before removal of configparser deprecations.

Second commit:

Update the deprecation warnings to explicitly call out that they will be removed in Python 3.12, and mention in What's New and a NEWS file.

Re:

• https://bugs.python.org/issue45173#msg411810
• https://mail.python.org/archives/list/python-dev@python.org/thread/GJTREADEXYAETECE5JDTPYWK4WMTKYGR/
• https://discuss.python.org/t/experience-with-python-3-11-in-fedora/12911

https://bugs.python.org/issue45173

[hugovk]

Should this (the second commit specifically) also go into 3.9 and 3.10 for greater visibility?

[vstinner]

cc @gpshead

[gpshead]

I think it seems reasonable for the second commit updating the warning message text to be backported to 3.10, but you should really ask the release manager @pablogsal. I wouldn't bother going as far back as 3.9 with that.

[pablogsal]

but you should really ask the release manager @pablogsal. I wouldn't bother going as far back as 3.9 with that.

I am ok backporting the error message to 3.10.

For 3.9 you should check with @ambv

[vstinner]

@gpshead @pablogsal: I'm the one who asked for the revert, but I would prefer if someone else merges this PR. Do you want to merge it?

[domdfcoding]

If the intention is to remove these for good in 3.12, it it worth noting that in the docs for readfp? Currently it only says that it's deprecated, but not that it's about to be removed.

[gpshead]

If the intention is to remove these for good in 3.12, it it worth noting that in the docs for readfp? Currently it only says that it's deprecated, but not that it's about to be removed.

I think this is fine. Keeping version numbers straight everywhere and sticking to them is hard enough. The important thing given we have a plan here is that the raised warnings now mention a version.

[miss-islington]

Thanks @hugovk for the PR, and @gpshead for merging it 🌮🎉.. I'm working now to backport this PR to: 3.10.
🐍🍒⛏🤖

[miss-islington]

Sorry @hugovk and @gpshead, I had trouble checking out the 3.10 backport branch.
Please backport using cherry_picker on command line.
cherry_picker e8659b47dece5a272111c0af5e340c364a9f807b 3.10

[gpshead]

feel free to assign warning message update backport PRs to me when you've made them.

[vstinner]

Python 3.10 didn't get a backward, only the doc was updated: ba4d79a