[New-bugs-announce] [issue44553] types.Union should support GC

[Ken Jin]

New submission from Ken Jin <kenjin4096 at gmail.com>:

types.Union objects can contain reference cycles, therefore causing memory leaks.

E.g.::

```
import sys, gc
from typing import TypeVar

gc.collect()
for _ in range(10):
 sys.gettotalrefcount()
 T = TypeVar('T')
 U = int | list[T]
 T.blah = U
 del T
 del U
 gc.collect()
```
Result:
84470
0
84488
0
84504
0
84520
0
84536
0

I'm sending a small PR soon to implement GC methods to fix this.

----------
messages: 396867
nosy: gvanrossum, kj
priority: normal
severity: normal
status: open
title: types.Union should support GC
versions: Python 3.10, Python 3.11

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue44553>
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