gh-111777: Fix assertion errors on incorrectly still-tracked GC object destruction #111778
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were not properly untracked before starting destruction, take care to untrack the object _before_ warning, to avoid triggering a GC run and causing the problem the code tries to warn about. Also make sure to save and restore any pending exceptions, which the warning would otherwise clobber or trigger an assertion error on.
Yhg1s
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needs backport to 3.11
pablogsal
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Nov 6, 2023
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Yeah, it's difficult to reproduce either real-world case. Deliberately setting an exception a custom tp_dealloc before calling PyObject_GC_Del is possible, but it's not really representative of the real case (the error would be set further up the call stack). The other case, with the warning triggering a GC run, I've completely failed to reproduce. It requires quite a complex interplay, apparently. I'm still debugging related issues, though, involving the untracking of GC objects, instances of heap types, subclassing in C, subclassing in Python, and custom tp_dealloc/tp_free, which has some subtle issues that elude me. I may be able to synthesise a good test in the end, but I think this fix is straight-forward enough to do without. And yes, this fix has solved crashes in two different extension modules with the same problem at Google (in Py_DEBUG mode), without us having to fix the warnings. (We'll still fix the warnings, but at least this unblocks further testing.) |
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Thanks @Yhg1s for the PR 🌮🎉.. I'm working now to backport this PR to: 3.11, 3.12. |
miss-islington
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Nov 12, 2023
… object destruction (pythonGH-111778) In PyObject_GC_Del, in Py_DEBUG mode, when warning about GC objects that were not properly untracked before starting destruction, take care to untrack the object _before_ warning, to avoid triggering a GC run and causing the problem the code tries to warn about. Also make sure to save and restore any pending exceptions, which the warning would otherwise clobber or trigger an assertion error on. (cherry picked from commit ce6a533) Co-authored-by: T. Wouters <[email protected]>
miss-islington
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Nov 12, 2023
… object destruction (pythonGH-111778) In PyObject_GC_Del, in Py_DEBUG mode, when warning about GC objects that were not properly untracked before starting destruction, take care to untrack the object _before_ warning, to avoid triggering a GC run and causing the problem the code tries to warn about. Also make sure to save and restore any pending exceptions, which the warning would otherwise clobber or trigger an assertion error on. (cherry picked from commit ce6a533) Co-authored-by: T. Wouters <[email protected]>
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GH-111989 is a backport of this pull request to the 3.12 branch. |
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GH-111990 is a backport of this pull request to the 3.11 branch. |
Yhg1s
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Nov 12, 2023
…C object destruction (GH-111778) (#111989) gh-111777: Fix assertion errors on incorrectly still-tracked GC object destruction (GH-111778) In PyObject_GC_Del, in Py_DEBUG mode, when warning about GC objects that were not properly untracked before starting destruction, take care to untrack the object _before_ warning, to avoid triggering a GC run and causing the problem the code tries to warn about. Also make sure to save and restore any pending exceptions, which the warning would otherwise clobber or trigger an assertion error on. (cherry picked from commit ce6a533) Co-authored-by: T. Wouters <[email protected]>
ambv
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Jan 17, 2024
…C object destruction (GH-111778) (GH-111990) In PyObject_GC_Del, in Py_DEBUG mode, when warning about GC objects that were not properly untracked before starting destruction, take care to untrack the object _before_ warning, to avoid triggering a GC run and causing the problem the code tries to warn about. Also make sure to save and restore any pending exceptions, which the warning would otherwise clobber or trigger an assertion error on. (cherry picked from commit ce6a533) Co-authored-by: T. Wouters <[email protected]>
aisk
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Feb 11, 2024
… object destruction (python#111778) In PyObject_GC_Del, in Py_DEBUG mode, when warning about GC objects that were not properly untracked before starting destruction, take care to untrack the object _before_ warning, to avoid triggering a GC run and causing the problem the code tries to warn about. Also make sure to save and restore any pending exceptions, which the warning would otherwise clobber or trigger an assertion error on.
Glyphack
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Sep 2, 2024
… object destruction (python#111778) In PyObject_GC_Del, in Py_DEBUG mode, when warning about GC objects that were not properly untracked before starting destruction, take care to untrack the object _before_ warning, to avoid triggering a GC run and causing the problem the code tries to warn about. Also make sure to save and restore any pending exceptions, which the warning would otherwise clobber or trigger an assertion error on.
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In PyObject_GC_Del, in Py_DEBUG mode, when warning about GC objects that were not properly untracked before starting destruction, take care to untrack the object before warning, to avoid triggering a GC run and causing the problem the code tries to warn about. Also make sure to save and restore any pending exceptions, which the warning would otherwise clobber or trigger an assertion error on.