Stop the git pane's file watch crashing the app - #292
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The git pane's FSEvents handler was written inside a `@MainActor` method, so the closure inherited main-actor isolation — and FSEvents calls it on the watcher's own utility queue. The first main-actor touch, filtering build products out of the event batch, hit Swift 6's executor check and took the whole app down with SIGTRAP. It fires whenever files change under a repo with the pane armed, so an agent's edit-build-look loop trips it repeatedly. `FolderEventStream`'s handler is `@Sendable` now, which forbids the silent isolation inheritance: the hop back to the main actor is the caller's explicit job, and forgetting it is a compile error rather than a crash on someone's desk. The pane's path test and its ignored-component set are `nonisolated` — they are pure string work — and the watched paths are captured immutably.
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termio dies with
SIGTRAPwhen files change under a repo whose git pane is armed. Crash reports show the FSEvents callback going throughswift_task_checkIsolated→dispatch_assert_queue_failinGitPanelModel.armWatcher().The handler closure is written inside a
@MainActormethod, so it inherits main-actor isolation.FolderEventStreamruns it on a utility queue, and the first main-actor touch — theisBuildProductEventfilter — trips Swift 6's executor check and kills the process. TheTask { @MainActor }hop at the end of the handler was correct; the work before it was not.Fixing only the one call would leave the trap armed for the next caller, so the fix is at the API boundary:
FolderEventStream's handler is@Sendable, which forbids isolation inheritance outright. That turns the same mistake into a compile error — it produced exactly the two errors this PR fixes, at the crash site.FileTreeWatcher, the other consumer, already delivers on.mainand needed no change.Hit repeatedly today during ordinary rebuilds: an agent's edit-build-look loop writes into the worktree constantly, which is exactly the trigger.
Verification
swift buildclean,swift test243/243. The compiler reproducing the defect is the regression guard — the isolation is now checked at build time rather than asserted at runtime. Not exercised on a running app; the runtime check is to open the Changes pane and write a file into the repo.Release Notes:
Fixed a crash when files changed on disk while the git pane was open.