Fix Swift 6 async let actor isolation crash#67
Fix Swift 6 async let actor isolation crash#67NickTrienens2025 wants to merge 1 commit intochristopherkarani:mainfrom
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| let surrogateMapTask: [UInt64: UInt64] = shouldPrefetchSurrogates | ||
| ? try await wax.surrogateFrameIds(for: sourceFrameIds) | ||
| : [:] | ||
| async let sourceFrameMetasTask: [UInt64: FrameMeta] = shouldPrefetchSurrogates | ||
| ? wax.frameMetas(frameIds: sourceFrameIds) | ||
| let sourceFrameMetasTask: [UInt64: FrameMeta] = shouldPrefetchSurrogates | ||
| ? try await wax.frameMetas(frameIds: sourceFrameIds) |
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These two immediate awaits run before expansion starts, so every denseCached request now pays for surrogateFrameIds + frameMetas on the critical path even when surrogate assembly is later skipped (for example, when expansion consumes the token budget). In the previous version this work was overlapped with expansion via async let; here it is fully serialized, which introduces avoidable latency in the common path. Keep the async-let workaround, but move these awaits into the surrogate phase (after expansion determines surrogates are still needed) to avoid front-loading this I/O.
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Replaces async let calls to actor-isolated methods with sequential awaits to fix a known compiler bug on macOS ARM64 that causes a swift_task_dealloc heap corruption. The async let task lowering in Swift 6 occasionally triggers a double-free of the task context when capturing self on an actor. Moving to sequential await avoids the compiler miscompilation.