gh-104415: Fix refleak tests for typing.ByteString deprecation

[sobolevn]

It passes now! 🎉

• Issue: test_typing fails refleak tests #104415

🤖 New build scheduled with the buildbot fleet by @sobolevn for commit e8f6c3d 🤖

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Looks good; I can reproduce the refleak locally, and confirmed this fixes it. So I'm happy to merge this to get the buildbots green again. Thanks!

I'm slightly confused about why this is necessary, though: I thought the warnings registry was cleared in the clear_caches function here:

cpython/Lib/test/libregrtest/utils.py

Lines 116 to 120 in b2c1b4d

	def clear_caches():
	# Clear the warnings registry, so they can be displayed again
	for mod in sys.modules.values():
	if hasattr(mod, '__warningregistry__'):
	del mod.__warningregistry__

And that clear_caches was called after each run when using the -R option:

cpython/Lib/test/libregrtest/refleak.py

Lines 189 to 190 in b2c1b4d

	# Clear caches
	clear_caches()

The root cause is that we cache ByteString in globals() here:

cpython/Lib/typing.py

Lines 3584 to 3586 in b2c1b4d

	ByteString = globals()["ByteString"] = _DeprecatedGenericAlias(
	collections.abc.ByteString, 0, removal_version=(3, 14)
	)

But libregrtest.utils.clear_caches doesn't know about that cache. It only knows to perform the cleanup functions we have in typing._cleanups:

cpython/Lib/test/libregrtest/utils.py

Lines 198 to 204 in b2c1b4d

	try:
	typing = sys.modules['typing']
	except KeyError:
	pass
	else:
	for f in typing._cleanups:
	f()

A better fix would be to do this instead:

diff --git a/Lib/typing.py b/Lib/typing.py
index bf7bd24197..cc38ef9b46 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -3586,3 +3586,13 @@ def __getattr__(attr):
             )
         return ByteString
     raise AttributeError(f"module 'typing' has no attribute {attr!r}")
+
+
+def _remove_ByteString_from_globals():
+    try:
+        del globals()["ByteString"]
+    except KeyError:
+        pass
+
+
+_cleanups.append(_remove_ByteString_from_globals)

And not touch anything in test_typing.py.

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Thanks!

I'll run the refleak buildbots again, just to double check this fixes things (it does on my machine)

🤖 New build scheduled with the buildbot fleet by @AlexWaygood for commit 023a615 🤖

If you want to schedule another build, you need to add the 🔨 test-with-refleak-buildbots label again.