Delete stale note about mp.Lock.acquire/SIGINT

[andmis]

The note I've deleted in this PR from the multiprocessing docs does not seem to be true anymore. (Or I'm misunderstanding something.)

~/tmp cat main.py
import threading
L = threading.Lock()
L.acquire()
print('got it')
L.acquire()
~/tmp python3.12 main.py
got it
^CTraceback (most recent call last):
  File "/Users/andrey/tmp/main.py", line 5, in <module>
    L.acquire()
KeyboardInterrupt
~/tmp:130

[ghost]

All commit authors signed the Contributor License Agreement.

[hauntsaninja]

Thanks for the PR! Looking at the tests / history, I don't think it's guaranteed that SIGINT will be handled in threading:

cpython/Lib/test/test_threadsignals.py

Lines 71 to 79 in 34920f3

	@unittest.skipIf(USING_PTHREAD_COND,
	'POSIX condition variables cannot be interrupted')
	@unittest.skipIf(sys.platform.startswith('linux') and
	not sys.thread_info.version,
	'Issue 34004: musl does not allow interruption of locks '
	'by signals.')
	# Issue #20564: sem_timedwait() cannot be interrupted on OpenBSD
	@unittest.skipIf(sys.platform.startswith('openbsd'),
	'lock cannot be interrupted on OpenBSD')

(I'm not sure how much that's up to date though, e.g. I couldn't reproduce on Alpine)

So it feels like this is still a useful additional guarantee to document. That said, Python did used to always ignore SIGINT in threading, and no longer does, so maybe we should say something like:

This differs from the behaviour of :mod:threading where on certain platforms SIGINT is
not guaranteed to be able to interrupt while the equivalent blocking calls are in progress.

[gpshead]

That text was from the original when multiprocessing was added. The behavior of threading locks in CPython changed in the 3.2 or 3.3 time-frame as we fixed our underlying implementation to use the right POSIX APIs. I agree, we don't need this text anymore. It is describing normal behavior of the module here and attempting to mention something about another module which isn't generally true anymore and even if it were, doesn't belong here.

[miss-islington-app]

Thanks @andmis for the PR, and @gpshead for merging it 🌮🎉.. I'm working now to backport this PR to: 3.12, 3.13.
🐍🍒⛏🤖

[bedevere-app]

GH-122078 is a backport of this pull request to the 3.13 branch.

[bedevere-app]

GH-122079 is a backport of this pull request to the 3.12 branch.