Clean up relay git file listing listeners (#3834)

src/relay/fs-handler-git-fallback.ts

@@ -38,6 +38,11 @@ export function listFilesWithGit(
 ): Promise<string[]> {
   const files = new Set<string>()
   const { primary, ignoredPass } = buildGitLsFilesArgsForQuickOpen(excludePathPrefixes)
+  const children: {
+    child: ReturnType<typeof spawn>
+    isDone: () => boolean
+    reject: (error: Error) => void
+  }[] = []
 
   const runGitLsFiles = (args: string[]): Promise<void> => {
     return new Promise((resolve, reject) => {
@@ -64,8 +69,41 @@ export function listFilesWithGit(
         env: buildRelayCommandEnv(),
         stdio: ['ignore', 'pipe', 'pipe']
       })
-      child.stdout!.setEncoding('utf-8')
-      child.stdout!.on('data', (chunk: string) => {
+      let timer: ReturnType<typeof setTimeout> | null = null
+      const cleanup = (): void => {
+        if (timer) {
+          clearTimeout(timer)
+          timer = null
+        }
+        child.stdout!.off('data', handleStdoutData)
+        child.stderr!.off('data', handleStderrData)
+        child.off('error', handleError)
+        child.off('close', handleClose)
+      }
+      const rejectPass = (error: Error): void => {
+        if (done) {
+          return
+        }
+        done = true
+        buf = ''
+        cleanup()
+        reject(error)
+      }
+      const resolvePass = (): void => {
+        if (done) {
+          return
+        }
+        done = true
+        cleanup()
+        resolve()
+      }
+      children.push({
+        child,
+        isDone: () => done,
+        reject: rejectPass
+      })
+
+      function handleStdoutData(chunk: string): void {
         buf += chunk
         let start = 0
         let idx = buf.indexOf('\n', start)
@@ -75,53 +113,62 @@ export function listFilesWithGit(
           idx = buf.indexOf('\n', start)
         }
         buf = start < buf.length ? buf.substring(start) : ''
-      })
-      child.stderr!.on('data', () => {
+      }
+      function handleStderrData(): void {
         /* drain */
-      })
-      child.once('error', (err) => {
+      }
+      function handleError(err: Error): void {
+        rejectPass(err)
+      }
+      function handleClose(_code: number | null, signal: NodeJS.Signals | null): void {
         if (done) {
           return
         }
-        done = true
-        clearTimeout(timer)
-        buf = ''
-        reject(err)
-      })
-      child.once('close', (_code, signal) => {
-        if (done) {
-          return
-        }
-        done = true
-        clearTimeout(timer)
         if (signal) {
           // Why: a signal exit means the child was killed (timeout or
           // external). Treat that as a load failure rather than silently
           // resolving with whatever git had managed to print.
-          buf = ''
-          reject(new Error(`git ls-files killed by ${signal}`))
+          rejectPass(new Error(`git ls-files killed by ${signal}`))
           return
         }
         if (buf) {
           processLine(buf)
         }
-        resolve()
-      })
-      const timer = setTimeout(() => {
-        if (done) {
-          return
-        }
-        done = true
-        buf = ''
+        resolvePass()
+      }
+
+      child.stdout!.setEncoding('utf-8')
+      child.stdout!.on('data', handleStdoutData)
+      child.stderr!.on('data', handleStderrData)
+      child.once('error', handleError)
+      child.once('close', handleClose)
+      timer = setTimeout(() => {
         child.kill()
-        reject(new Error('git ls-files timed out'))
+        rejectPass(new Error('git ls-files timed out'))
       }, 10_000)
     })
   }
 
-  return Promise.all([runGitLsFiles(primary), runGitLsFiles(ignoredPass)]).then(() =>
-    Array.from(files)
-  )
+  const killSurvivors = (): void => {
+    // Why: Promise.all returns after the first failed pass, but the sibling
+    // git process can keep streaming on SSH unless we cancel it explicitly.
+    for (const entry of children) {
+      if (entry.isDone()) {
+        continue
+      }
+      if (entry.child.exitCode === null && entry.child.signalCode === null) {
+        entry.child.kill()
+      }
+      entry.reject(new Error('git ls-files canceled after sibling failure'))
+    }
+  }
+
+  return Promise.all([runGitLsFiles(primary), runGitLsFiles(ignoredPass)])
+    .then(() => Array.from(files))
+    .catch((err) => {
+      killSurvivors()
+      throw err
+    })
 }
 
 /**

src/relay/fs-handler-list-files-ignored.test.ts

@@ -154,6 +154,14 @@ describe('relay quick open ignored file listing', () => {
       expect(outcome).toContain('git ls-files timed out')
       expect(primaryProc.kill).toHaveBeenCalled()
       expect(ignoredProc.kill).toHaveBeenCalled()
+      expect((primaryProc.stdout as unknown as EventEmitter).listenerCount('data')).toBe(0)
+      expect((primaryProc.stderr as unknown as EventEmitter).listenerCount('data')).toBe(0)
+      expect(primaryProc.listenerCount('error')).toBe(0)
+      expect(primaryProc.listenerCount('close')).toBe(0)
+      expect((ignoredProc.stdout as unknown as EventEmitter).listenerCount('data')).toBe(0)
+      expect((ignoredProc.stderr as unknown as EventEmitter).listenerCount('data')).toBe(0)
+      expect(ignoredProc.listenerCount('error')).toBe(0)
+      expect(ignoredProc.listenerCount('close')).toBe(0)
     } finally {
       vi.useRealTimers()
     }