gh-117657: Fix data races reported by TSAN in some set methods

[aisk]

set_add_key and set_discard_key have the same issue and should be fixed, although they have not been detected by TSAN.

After this change, the TSAN doesn't report data races for this method on my machine.

• Issue: Make TSAN tests pass with the GIL disabled in free-threaded builds #117657

[colesbury]

Thanks! This pattern occurs in a bunch of places outside of setobject.c. Can you fix those as well? I think it's worth fixing the entire pattern at once.

I think it's also probably worth refactoring the fast hash check into its own inline function (maybe in pycore_object.h or pycore_unicodeobject.h) that does the whole check the type, check the unicode hash, return it if it's not -1, otherwise delegate to PyObject_Hash().

[aisk]

Thanks! This pattern occurs in a bunch of places outside of setobject.c. Can you fix those as well? I think it's worth fixing the entire pattern at once.

I think it's also probably worth refactoring the fast hash check into its own inline function (maybe in pycore_object.h or pycore_unicodeobject.h) that does the whole check the type, check the unicode hash, return it if it's not -1, otherwise delegate to PyObject_Hash().

Thanks for the review! I think this new function is not related to unicode object only, so I added it in pycore_object.h, and named it _PyObject_HashFast().

[colesbury]

Thanks - this looks good. Just minor comments about _PyObject_HashFast

[colesbury]

Thanks! LGTM

[miss-islington-app]

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

[bedevere-app]

GH-121240 is a backport of this pull request to the 3.13 branch.

[vstinner]

Nice change, I like _PyObject_HashFast() which factorizes the code.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 Debian root 3.13 has failed when building commit 06fd745.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/all/#builders/1441/builds/255) and take a look at the build logs.
4. Check if the failure is related to this commit (06fd745) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/all/#builders/1441/builds/255

Failed tests:

• test_repl

Failed subtests:

• test_asyncio_repl_is_ok - test.test_repl.TestInteractiveInterpreter.test_asyncio_repl_is_ok

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File "/root/buildarea/3.13.angelico-debian-amd64/build/Lib/asyncio/__main__.py", line 109, in run
    raise OSError(errno.ENOTTY, "tty required", "stdin")
xiting asyncio REPL...
Fatal Python error: _enter_buffered_busy: could not acquire lock for <_io.BufferedWriter name='<stderr>'> at interpreter shutdown, possibly due to daemon threads
Python runtime state: finalizing (tstate=0x0000557e5090ff50)


Traceback (most recent call last):
xiting asyncio REPL...
  File "/root/buildarea/3.13.angelico-debian-amd64/build/Lib/asyncio/__main__.py", line 109, in run
    raise OSError(errno.ENOTTY, "tty required", "stdin")
Fatal Python error: _enter_buffered_busy: could not acquire lock for <_io.BufferedWriter name='<stderr>'> at interpreter shutdown, possibly due to daemon threads
Python runtime state: finalizing (tstate=0x0000561498692f50)


Traceback (most recent call last):
  File "/root/buildarea/3.13.angelico-debian-amd64/build/Lib/test/test_repl.py", line 199, in test_asyncio_repl_is_ok
    assert_python_ok("-m", "asyncio")
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/root/buildarea/3.13.angelico-debian-amd64/build/Lib/test/support/script_helper.py", line 180, in assert_python_ok
    return _assert_python(True, *args, **env_vars)
  File "/root/buildarea/3.13.angelico-debian-amd64/build/Lib/test/support/script_helper.py", line 165, in _assert_python
    res.fail(cmd_line)
    ~~~~~~~~^^^^^^^^^^
  File "/root/buildarea/3.13.angelico-debian-amd64/build/Lib/test/support/script_helper.py", line 75, in fail
    raise AssertionError("Process return code is %d\n"
    ...<13 lines>...
                            err))
AssertionError: Process return code is -6
command line: ['/root/buildarea/3.13.angelico-debian-amd64/build/python', '-X', 'faulthandler', '-I', '-m', 'asyncio']

[colesbury]

Buildbot failure is unrelated to this PR.

See #119909