fix: make ExitWaiter.doExit idempotent to avoid double-resume crash#1861
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radheradhe01 wants to merge 2 commits into
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fix: make ExitWaiter.doExit idempotent to avoid double-resume crash#1861radheradhe01 wants to merge 2 commits into
radheradhe01 wants to merge 2 commits into
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### Problem
`ExitWaiter.doExit` resumes every stored continuation but never guards against being called twice and never clears the array:
```swift
public func doExit(exitStatus: ExitStatus) {
for cc in continuations {
cc.resume(returning: exitStatus)
}
self.exitStatus = exitStatus
}
```
`doExit` can be reached more than once for the same process. In the exec path, the registered `onExit` callback calls `releaseWaiters` (→ `doExit`) and then performs further work that can throw (`process.delete()`); `ExitMonitor.track` catches that error and invokes the **same** `onExit` again, calling `doExit` a second time. Resuming a `CheckedContinuation` twice is a fatal trap.
### Fix
Make `doExit` idempotent: return early if the exit has already been recorded, set `exitStatus` first, and clear the continuations before resuming them so they cannot be resumed again.
### Notes
All access is serialized on the owning actor; the guard simply makes the "exit fires once" invariant explicit and crash-safe.
radheradhe01
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Type of Change
Motivation and Context
ExitWaiter.doExitresumes every stored continuation but never guards against being called twice and never clears the array.doExitcan be reached more than once for the same process: in the exec path the registeredonExitcallsreleaseWaiters(→doExit) and then performs further work that can throw (process.delete());ExitMonitor.trackcatches that error and invokes the sameonExitagain, callingdoExita second time. Resuming aCheckedContinuationtwice is a fatal trap.This change makes
doExitidempotent: it returns early if the exit has already been recorded, setsexitStatusfirst, and clears the continuations before resuming them so they cannot be resumed again. All access is serialized on the owning actor; the guard makes the "exit fires once" invariant explicit and crash-safe.Testing
Verified by static / code-level review; not built locally (no macOS 26 toolchain available here) — CI build will validate.