GeezerVison is showing github.com — [3.15] gh-159739: Preserve ContextVar cache updates from finalizers (GH-160197) by miss-islington · Pull Request #160330 · python/cpython
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Oct 22, 2026
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Resetting a ContextVar can finalize the replaced value, whose finalizer may set the variable again. Updating the lookup cache after releasing the old context root overwrites that newer cached value, so get() can return a stale value or use a freed object. Update the cache before the old root can be released. Backport to 3.15 and 3.14.
(cherry picked from commit f4f8b93)
Co-authored-by: Jelle Zijlstra [email protected]
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…ythonGH-160197)
Resetting a ContextVar can finalize the replaced value, whose finalizer may set the variable again. Updating the lookup cache after releasing the old context root overwrites that newer cached value, so get() can return a stale value or use a freed object. Update the cache before the old root can be released. Backport to 3.15 and 3.14.
(cherry picked from commit f4f8b93)
Co-authored-by: Jelle Zijlstra <[email protected]>
This was referenced Oct 22, 2026
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