gh-145235: Make dict watcher API thread-safe for free-threaded builds#145233
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colesbury
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Feb 25, 2026
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@colesbury Thank you for the review. I’ve addressed the comments. |
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Could we please add the |
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This PR is stale because it has been open for 30 days with no activity. |
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needs backport to 3.15
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Thanks @yoney for the PR, and @colesbury for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14, 3.15. |
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GH-149690 is a backport of this pull request to the 3.15 branch. |
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GH-149691 is a backport of this pull request to the 3.14 branch. |
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… builds (gh-145233) (#149690) In free-threaded builds, concurrent calls to PyDict_AddWatcher, PyDict_ClearWatcher, PyDict_Watch, and PyDict_Unwatch can race on the shared callback array and the per-dict watcher tags. This change adds a mutex to serialize watcher registration and removal, atomic operations for tag updates, and atomic acquire/release synchronization for callback dispatch in _PyDict_SendEvent. (cherry picked from commit 8a48959) Co-authored-by: Alper <alperyoney@fb.com>
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… builds (gh-145233) (#149691) In free-threaded builds, concurrent calls to PyDict_AddWatcher, PyDict_ClearWatcher, PyDict_Watch, and PyDict_Unwatch can race on the shared callback array and the per-dict watcher tags. This change adds a mutex to serialize watcher registration and removal, atomic operations for tag updates, and atomic acquire/release synchronization for callback dispatch in _PyDict_SendEvent. (cherry picked from commit 8a48959) Co-authored-by: Alper <alperyoney@fb.com>
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In free-threaded builds, concurrent calls to
PyDict_AddWatcher,PyDict_ClearWatcher,PyDict_Watch, andPyDict_Unwatchcan race on the shared callback array and the per-dict watcher tags. This change adds a mutex to serialize watcher registration and removal, atomic operations for tag updates, and atomic acquire/release synchronization for callback dispatch in_PyDict_SendEvent.Note: Before this change, running
test.test_free_threading.test_dict_watcheremitted tsan warnings in the free-threaded tsan build.cc: @colesbury @mpage @DinoV