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[Utilities] Stop the array pool trim timer from capturing the execution context - #152
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🟢 Approval recommended
No active review issues remain for the change to prevent pool timers from retaining ambient AsyncLocal values.
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What changed in this PR
Prevents FixedSizeArrayPool bucket timers from retaining ambient AsyncLocal values, avoiding unintended object retention for the timer’s lifetime.
Changes:
- Suppresses execution context flow during timer creation and restores the prior flow state afterward, leaving callback and trimming behavior unchanged.
- Adds a regression test verifying that an
AsyncLocalvalue can be collected while the pool remains alive.
| File | Description |
|---|---|
src/HotChocolate/Utilities/test/Utilities.Tests/FixedSizeArrayPoolTests.cs |
Tests collection of an ambient AsyncLocal value after pool creation. |
src/HotChocolate/Utilities/src/Utilities.Buffers/FixedSizeArrayPool.cs |
Creates trim timers without capturing the execution context. |
Review effort: Balanced
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The trim timer of
FixedSizeArrayPoolbuckets captured the execution context of the code that first created the pool. AnyAsyncLocalvalue that was set at that point, for example a DataLoader scope, stayed reachable for as long as the timer lived.The bucket now creates its timer with execution context flow suppressed, and restores the flow right afterwards. The timer callback and the trim policy are unchanged. The bucket timer is the only timer in Utilities.Buffers.
Tests:
FixedSizeArrayPoolTests.Constructor_Should_NotRetainAsyncLocalValue_When_PoolIsCreatedInScopechecks that anAsyncLocalvalue set while the pool is created can be collected. It fails without the fix.No benchmark was run. The change runs once per bucket creation, not when arrays are rented or returned.