PS: It would be good to merge this not only in Python 3.12, but also older versions (3.11, 3.10, 3.9, 3.8).

PS: It would be good to merge this not only in Python 3.12, but also older versions (3.11, 3.10, 3.9, 3.8).

3.8 and 3.9 are now only accepting security-related patches, so this definitely won't be backported that far, I'm afraid.

3.8 and 3.9 are now only accepting security-related patches, so this definitely won't be backported that far, I'm afraid.

Fair enough. In that case, I propose to target 3.10, 3.11, and 3.12.

As mentioned in the issue I'm skeptical that this is something we should fix in typing.py. I'll ask for input from other core devs (after the dust from the 3.11 release settles).

I'm skeptical too. I feel that the tool is incorrectly blaming typing.py.

@gvanrossum, did you see the discussion in #98253? When I first reported the issue, the actual source of these refleaks was mysterious. Further along the discussion thread, the problem was finally tracked down (see post #98253 (comment))

The problem is that the caching mechanism in typing.py can turn virtually any refleak in any typed extension module into refleaks elsewhere. That makes it really difficult to develop leak-free extensions, because any systematic checking for leaks runs into flukes. My tests show that many of the bigger packages (pandas, pytorch, tensorflow) include some refleaks that are problematic in this context.

The patch in this PR is simple and it breaks this problematic chain of references. Of course, one could say: let's leave typing.py as-is and fix all of the other extension modules. I just don't think it is very practical to do so.