Fix thread-safety race in SFUserAccount encodeWithCoder#4042
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brandonpage merged 1 commit intoMay 29, 2026
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encodeWithCoder accessed ivars directly without synchronizing on the concurrent queue, while setters (setAccessScopes, setIdData, setCustomDataObject:forKey:) use dispatch_barrier_async. This caused a race where encoding immediately after setting these properties could capture stale (nil/empty) values. Wrap the encoder calls in dispatch_sync on _syncQueue so pending barrier writes complete before the ivars are read. Fixes testUserAccountEncoding failures on iOS 26 nightly CI.
Clang Static Analysis Issues
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## dev #4042 +/- ##
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- Coverage 70.67% 68.15% -2.53%
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Files 245 245
Lines 21462 21464 +2
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- Hits 15169 14629 -540
- Misses 6293 6835 +542
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wmathurin
approved these changes
May 22, 2026
bbirman
approved these changes
May 22, 2026
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Summary
encodeWithCoder:accessed ivars (_accessScopes,_idData,_customData) directly without synchronizing on the concurrent queue, while their setters usedispatch_barrier_async. This caused a race where encoding immediately after setting these properties could capture stale (nil/empty) values.dispatch_syncon_syncQueueso pending barrier writes complete before the ivars are read.Test plan
testUserAccountEncodingpasses on iOS 26 (Xcode 26) nightly CISFUserAccountfrom different threads