gh-83274: Don't crash when a Tcl interpreter is deallocated in the wrong thread#152323
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serhiy-storchaka merged 3 commits intoJun 27, 2026
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…the wrong thread
Deallocating the interpreter from a thread other than the one it was created
in ran Tcl_DeleteInterp() there, which makes Tcl abort the process
("Tcl_AsyncDelete: async handler deleted by the wrong thread").
Tkapp_Dealloc() now leaks the interpreter in that case and reports a
RuntimeWarning instead.
Co-Authored-By: E. Paine <63801254+E-Paine@users.noreply.github.com>
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
serhiy-storchaka
added
needs backport to 3.13
…ded build On the free-threaded build the interpreter may be deallocated in its own thread (deferred reference counting), so the RuntimeWarning is not emitted. The no-crash guarantee is still checked by assert_python_ok(). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Thanks @serhiy-storchaka for the PR 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14, 3.15. |
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Sorry, @serhiy-storchaka, I could not cleanly backport this to |
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Sorry, @serhiy-storchaka, I could not cleanly backport this to |
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Sorry, @serhiy-storchaka, I could not cleanly backport this to |
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Dropping the last reference to a tkinter object from a thread other than the one its Tcl interpreter was created in ran
Tcl_DeleteInterp()in that thread, which makes Tcl abort the whole process (Tcl_AsyncDelete: async handler deleted by the wrong thread). This typically happens when a tkinter object leaks into another thread and is garbage-collected there.Tkapp_Dealloc()now checks the interpreter's thread and, when called in the wrong one, skipsTcl_DeleteInterp()and reports aRuntimeWarning(through the warnings machinery, so it can be filtered) instead of crashing. The interpreter is leaked, but it is small and can no longer be used once Python has dropped it.Based on the approach in the draft PR #21532 by E. Paine.