test(git-watch): reserve replacement root inode

src/main/ipc/git-metadata-poll-scheduler.ts

@@ -67,14 +67,11 @@ export class GitMetadataPollScheduler {
   private nextId = 1
   private activePolls = 0
   private activeFilesystemOperations = 0
-  private resetGeneration = 0
-  private now: () => number
 
   constructor(
     private readonly concurrency = GIT_METADATA_FILESYSTEM_CONCURRENCY,
-    now: () => number = () => performance.now()
+    private readonly now: () => number = () => performance.now()
   ) {
-    this.now = now
     if (!Number.isInteger(concurrency) || concurrency < 1) {
       throw new Error('Git metadata scheduler concurrency must be a positive integer')
     }
@@ -163,28 +160,6 @@ export class GitMetadataPollScheduler {
     return promise
   }
 
-  setNowForTests(now: () => number): void {
-    this.now = now
-  }
-
-  resetForTests(): void {
-    this.resetGeneration++
-    if (this.timer) {
-      clearTimeout(this.timer)
-      this.timer = null
-    }
-    for (const poll of this.polls.values()) {
-      poll.disposed = true
-      poll.unsubscribeVisibility()
-      poll.queued = false
-    }
-    this.polls.clear()
-    this.pollQueue.length = 0
-    this.filesystemQueue.length = 0
-    this.activePolls = 0
-    this.activeFilesystemOperations = 0
-  }
-
   private unsubscribePoll(poll: ScheduledPoll): void {
     if (poll.disposed) {
       return
@@ -277,7 +252,6 @@ export class GitMetadataPollScheduler {
       }
       const isVisibilityCatchUp = poll.pendingVisibilityCatchUp
       poll.pendingVisibilityCatchUp = false
-      const resetGeneration = this.resetGeneration
       poll.running = true
       this.activePolls++
       let result: void | Promise<void>
@@ -291,9 +265,6 @@ export class GitMetadataPollScheduler {
           // Each poller owns its transient-error policy; keep the host scheduler alive.
         })
         .finally(() => {
-          if (resetGeneration !== this.resetGeneration) {
-            return
-          }
           poll.running = false
           this.activePolls--
           if (!poll.disposed && poll.rerunPending) {
@@ -310,12 +281,8 @@ export class GitMetadataPollScheduler {
   private drainFilesystemQueue(): void {
     while (this.activeFilesystemOperations < this.concurrency && this.filesystemQueue.length > 0) {
       const operation = this.filesystemQueue.shift()!
-      const resetGeneration = this.resetGeneration
       this.activeFilesystemOperations++
       void operation.execute().finally(() => {
-        if (resetGeneration !== this.resetGeneration) {
-          return
-        }
         this.activeFilesystemOperations--
         this.drainFilesystemQueue()
       })

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

@@ -1,4 +1,4 @@
-import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { afterEach, describe, expect, it, vi } from 'vitest'
 import { appendFile, mkdtemp, mkdir, realpath, rm, writeFile } from 'node:fs/promises'
 import type * as NodeFsPromises from 'node:fs/promises'
 import { performance as nodePerformance } from 'node:perf_hooks'
@@ -18,17 +18,10 @@ import type {
 } from './worktree-base-directory-poller'
 import { startGitCommonWatch } from './worktree-git-common-watch'
 import { startGitCommonPolling } from './worktree-git-common-polling'
-import { gitMetadataPollScheduler } from './git-metadata-poll-scheduler'
 
 vi.mock('./parcel-watcher-process', () => ({
   subscribeViaWatcherProcess: vi.fn()
 }))
-
-beforeEach(() => {
-  gitMetadataPollScheduler.resetForTests()
-  gitMetadataPollScheduler.setNowForTests(() => Date.now())
-})
-
 // Records every stat target so a test can assert which paths a parked poll stopped touching.
 const { statCalls } = vi.hoisted(() => ({ statCalls: [] as string[] }))
 
@@ -54,6 +47,20 @@ const alwaysVisible: WorktreePollerWindowVisibility = {
   onWindowBecameVisible: () => () => {}
 }
 
+async function replaceWorktreesRoot(
+  commonDir: string,
+  worktreesDir: string,
+  retainedEntry: string
+): Promise<void> {
+  await rm(worktreesDir, { recursive: true })
+  // Linux can reuse a just-deleted directory inode. Reserve that inode with a
+  // sibling before recreating the watched root so reconciliation sees a replacement.
+  const inodeReservation = join(commonDir, 'worktrees-replacement-inode')
+  await mkdir(inodeReservation)
+  await mkdir(retainedEntry, { recursive: true })
+  await rm(inodeReservation, { recursive: true, force: true })
+}
+
 function createVisibilityHarness(): {
   source: WorktreePollerWindowVisibility
   hide: () => void
@@ -100,7 +107,6 @@ describe('worktree git-common narrow watch (darwin)', () => {
 
   afterEach(async () => {
     await Promise.all(cleanups.splice(0).map((cleanup) => cleanup()))
-    gitMetadataPollScheduler.resetForTests()
     childSubscriptions = []
     statCalls.length = 0
     subscribeMock.mockReset()
@@ -524,7 +530,6 @@ describe('worktree git-common narrow watch (darwin)', () => {
 
   it('re-arms the native stream when the root is replaced with the same child names', async () => {
     vi.useFakeTimers()
-    vi.clearAllTimers()
     const restorePerformanceNow = vi
       .spyOn(nodePerformance, 'now')
       .mockImplementation(() => Date.now())
@@ -538,18 +543,9 @@ describe('worktree git-common narrow watch (darwin)', () => {
       await startWatch(commonDir, received)
       const staleSubscription = childSubscriptions[0]
 
-      await rm(worktreesDir, { recursive: true })
-      await mkdir(retainedEntry, { recursive: true })
+      await replaceWorktreesRoot(commonDir, worktreesDir, retainedEntry)
       await vi.advanceTimersByTimeAsync(POLL_MS * RECONCILIATION_TICKS * 4)
-      await vi.runOnlyPendingTimersAsync()
-      // Native filesystem promises settle outside the fake timer callback; wait for the
-      // re-subscribe observable rather than relying on timer advancement to flush them.
-      await vi.waitFor(
-        () => {
-          expect(subscribeMock).toHaveBeenCalledTimes(2)
-        },
-        { timeout: 1_000 }
-      )
+      expect(subscribeMock).toHaveBeenCalledTimes(2)
       expect(staleSubscription.unsubscribe).toHaveBeenCalledOnce()
 
       const beforeStaleEvent = received.length
@@ -568,7 +564,6 @@ describe('worktree git-common narrow watch (darwin)', () => {
 
   it('disposes an in-flight stale resubscribe and fences its interruption hook', async () => {
     vi.useFakeTimers()
-    vi.clearAllTimers()
     const restorePerformanceNow = vi
       .spyOn(nodePerformance, 'now')
       .mockImplementation(() => Date.now())
@@ -589,31 +584,16 @@ describe('worktree git-common narrow watch (darwin)', () => {
       const onWatchError = vi.fn()
       await startWatch(commonDir, received, () => [], onWatchError)
 
-      await rm(worktreesDir, { recursive: true })
-      await mkdir(retainedEntry, { recursive: true })
+      await replaceWorktreesRoot(commonDir, worktreesDir, retainedEntry)
       await vi.advanceTimersByTimeAsync(POLL_MS * RECONCILIATION_TICKS * 4)
-      await vi.runOnlyPendingTimersAsync()
-      await vi.waitFor(
-        () => {
-          expect(subscribeMock).toHaveBeenCalledTimes(2)
-        },
-        { timeout: 1_000 }
-      )
+      expect(subscribeMock).toHaveBeenCalledTimes(2)
       const stalePendingSubscription = childSubscriptions[1]
 
-      await rm(worktreesDir, { recursive: true })
-      await mkdir(retainedEntry, { recursive: true })
+      await replaceWorktreesRoot(commonDir, worktreesDir, retainedEntry)
       await vi.advanceTimersByTimeAsync(POLL_MS * RECONCILIATION_TICKS * 4)
-      await vi.waitFor(
-        () => {
-          expect(
-            received
-              .flat()
-              .filter((event) => event.type === 'create' && event.path === worktreesDir)
-          ).toHaveLength(2)
-        },
-        { timeout: 1_000 }
-      )
+      expect(
+        received.flat().filter((event) => event.type === 'create' && event.path === worktreesDir)
+      ).toHaveLength(2)
 
       const beforeStaleInterruption = received.length
       stalePendingSubscription.hooks.onInterruption?.()
@@ -626,12 +606,7 @@ describe('worktree git-common narrow watch (darwin)', () => {
         }
       })
       await vi.advanceTimersByTimeAsync(POLL_MS)
-      await vi.waitFor(
-        () => {
-          expect(subscribeMock).toHaveBeenCalledTimes(3)
-        },
-        { timeout: 1_000 }
-      )
+      expect(subscribeMock).toHaveBeenCalledTimes(3)
       expect(stalePendingSubscription.unsubscribe).toHaveBeenCalledOnce()
 
       const immediateEntry = join(worktreesDir, 'current-generation')
@@ -671,7 +646,6 @@ describe('worktree git-common polling gate (non-darwin)', () => {
 
   afterEach(async () => {
     await Promise.all(cleanups.splice(0).map((cleanup) => cleanup()))
-    gitMetadataPollScheduler.resetForTests()
   })
 
   async function makePollingCommonDir(): Promise<string> {