GH-91636: Clear weakrefs created by finalizers. #136401
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Weakrefs to unreachable garbage that are created during running of finalizers need to be cleared. This avoids exposing objects that have `tp_clear` called on them to Python-level code.
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@colesbury In case you want to look at the free_threading_gc changes. |
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Looks good to me. |
colesbury
reviewed
Jul 8, 2025
Add a boolean flag to indicate that callbacks should be enabled. This allows the same function to be used before and after finalizer execution.
| if (!allow_callbacks) { | ||
| return 0; | ||
| } | ||
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Maybe it is worth to add an assert here for old != NULL?
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Similar question: The old and allow_callbacks arguments are orthogonal even in older versions?
AndPuQing
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Jul 11, 2025
Weakrefs to unreachable garbage that are created during running of finalizers need to be cleared. This avoids exposing objects that have `tp_clear` called on them to Python-level code.
Pranjal095
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Jul 12, 2025
Weakrefs to unreachable garbage that are created during running of finalizers need to be cleared. This avoids exposing objects that have `tp_clear` called on them to Python-level code.
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Weakrefs to unreachable garbage that are created during running of finalizers need to be cleared. This avoids exposing objects that have
tp_clearcalled on them to Python-level code.Note that this is part of the GH-136189 change, split out to make it easier for back-porting. This change is conceptually quite simple and is a candidate to backport to all older Python versions (this bug existed for a long time, perhaps in version 2.3). There is some duplicated code between
handle_finalizersandclear_finalizersbut I think it's simpler just to leave that duplication. In the "main" branch I'll clean that up.