Allow continuations to have no ExecutionContext#128323
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`ValueTaskContinuation` does not need to save/restore ExecutionContext, and also in the future we expect to allow continuations to skip this restoration when the JIT proved that it is not going to be looked at.
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Pull request overview
This PR updates the CoreCLR runtime-async continuation machinery to support continuations that do not carry an ExecutionContext slot, and applies that to the hand-rolled ValueTaskContinuation so it no longer captures/restores ExecutionContext.
Changes:
- Removed
ExecutionContextstorage/initialization fromValueTaskContinuation. - Replaced
GetExecutionContext()withTryGetExecutionContext(out ...)and made dispatch restore conditional on an encoded EC slot being present. - Stopped capturing
ExecutionContextwhen constructingValueTaskContinuationforTransparentAwaitValueTask{OfT}.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.ValueTaskContinuation.cs | Removes the ExecutionContext field and related flag encoding/clearing from the hand-rolled ValueTask continuation. |
| src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs | Adds TryGetExecutionContext and updates continuation dispatch to restore EC only when the continuation encodes an EC slot; removes EC capture for ValueTask continuation setup. |
jkotas
added
area-System.Threading.Tasks
runtime-async
and removed
area-System.Reflection
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Tagging subscribers to this area: @dotnet/area-system-threading-tasks |
This was referenced May 18, 2026
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PTAL @VSadov |
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ValueTaskContinuationdoes not need to save/restore ExecutionContext, and also in the future we expect to allow continuations to skip this save/restore when the JIT proved that it is not going to be looked at.