[issue38006] Crash in remove() weak reference callback of weakref.WeakValueDictionary at Python exit

[STINNER Victor]

STINNER Victor <vstinner at python.org> added the comment:

> 1. Docs should be changed to encourage implementing the full gc protocol for "all" containers.  Spell out what can go wrong if they don't.  Be upfront about that history has, at times, proved us too optimistic about that ever since weakrefs were added.

Would it make any sense to add an opt-in option to emit a warning when a new type is created with Py_TPFLAGS_HAVE_GC but it doesn't implement tp_traverse? Maybe also emit a warning if it doesn't implement tp_clear?

Maybe it could be a ResourceWarning emitted in development mode, when -X dev is used on the command line.

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue38006>
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