Fix cancellation submission race#389
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davidkoski merged 2 commits intoJul 14, 2026
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TokenIterator.next() calls asyncEval() to pipeline the next GPU evaluation. The
3.x loop `tokenLoop: while let token = iterator.next()` checked Task.isCancelled
only AFTER next() had already submitted work, allowing one extra asyncEval after
cancellation was observed.
Reorder to `while !Task.isCancelled { guard let token = iterator.next() else { break } }`
so the check happens before next(). The existing post-loop block already assigns
stopReason = .cancelled on a cancelled exit, and Stream().synchronize() still settles
any in-flight evaluation at the end of the task body, so the settlement boundary is
unchanged.
3.x re-authoring of the 2.x fix (0737a6e), adapted to the refactored tokenLoop shape.
Fixes the iOS/iPadOS lifecycle crash when the app backgrounds mid-generation:
[METAL] Command buffer execution failed: Insufficient Permission
(kIOGPUCommandBufferCallbackErrorBackgroundExecutionNotPermitted)
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Ports the 2.x settlement tests (b03a2b7) to 3.x: stream-cancellation settle, immediate-cancel settle, .cancelled stopReason, and .length at maxTokens (the guard-nil natural-termination path). Compile-verified against 3.31.4. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Rebase on current main. |
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Proposed changes
Fixes #382
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