fix(watcher): ignore callbacks from replaced git-common watches

src/main/ipc/worktree-git-common-watch.test.ts

@@ -128,6 +128,17 @@ describe('worktree git-common narrow watch (darwin)', () => {
     await vi.waitFor(() => {
       expect(subscribeMock).toHaveBeenCalledTimes(2)
     })
+
+    const receivedAfterRearm = received.length
+    childSubscriptions[0].callback(new Error('late error from replaced watcher'), [])
+    childSubscriptions[0].callback(null, [
+      { type: 'create', path: join(worktreesDir, 'late-old-event') }
+    ])
+    childSubscriptions[0].hooks.onInterruption?.()
+
+    // A replaced watch cannot tear down its successor or report stale events.
+    expect(received).toHaveLength(receivedAfterRearm)
+    expect(childSubscriptions[1].unsubscribe).not.toHaveBeenCalled()
   })
 
   it('reports a structural change after a watcher-child interruption', async () => {

src/main/ipc/worktree-git-common-watch.ts

@@ -162,12 +162,14 @@ async function startGitCommonNarrowWatch(
       return false
     }
     let errored = false
+    let active = true
     // Why: parcel tears its native stream down when the watched root is
     // deleted (e.g. `git worktree prune` removing an empty worktrees dir) —
     // sometimes surfaced as an error, sometimes as a delete event for the
     // root. Either way: notify, drop the dead stream, and let the existence
     // poll re-arm when a future worktree add recreates the dir.
     const teardownAndRearm = (): void => {
+      active = false
       errored = true
       const current = subscription
       subscription = null
@@ -180,7 +182,7 @@ async function startGitCommonNarrowWatch(
       const sub = await subscribeViaWatcherProcess(
         worktreesDir,
         (error, events) => {
-          if (disposed) {
+          if (disposed || !active) {
             return
           }
           if (error) {
@@ -203,7 +205,7 @@ async function startGitCommonNarrowWatch(
           // Why: a watcher-child crash drops events during the automatic
           // resubscribe gap; report a structural change so worktrees re-sync.
           onInterruption: () => {
-            if (!disposed) {
+            if (!disposed && active) {
               onEvents([{ type: 'update', path: worktreesDir }])
             }
           }