vitest-dev
diff --git a/‎packages/vitest/src/node/pools/poolRunner.ts‎
Lines changed: 3 additions & 1 deletion b/‎packages/vitest/src/node/pools/poolRunner.ts‎
Lines changed: 3 additions & 1 deletion
diff --git a/‎packages/vitest/src/node/pools/workers/forksWorker.ts‎
Lines changed: 55 additions & 2 deletions b/‎packages/vitest/src/node/pools/workers/forksWorker.ts‎
Lines changed: 55 additions & 2 deletions
@@ -277,8 +277,10 @@ export class PoolRunner {
     try {
       this._state = RunnerState.STOPPING
 
-      // Remove exit listener early to avoid "unexpected exit" errors during shutdown
+      // Remove exit and error listeners early to avoid "unexpected exit" and
+      // channel teardown errors during shutdown
       this.worker.off('exit', this.emitUnexpectedExit)
+      this.worker.off('error', this.emitWorkerError)
 
       const stopSpan = this.startTracesSpan('vitest.worker.stop')
       await this.withTimeout(
 
@@ -2,10 +2,14 @@ import type { ChildProcess } from 'node:child_process'
 import type { Writable } from 'node:stream'
 import type { PoolOptions, PoolWorker, WorkerRequest } from '../types'
 import { fork } from 'node:child_process'
+import { EventEmitter } from 'node:events'
 import { resolve } from 'node:path'
 import { streamFlushed } from './utils'
 
 const SIGKILL_TIMEOUT = 500 /** jest does 500ms by default, let's follow it */
+// how long a failed pipe write may wait for the process's 'exit' event
+// before it is reported as the worker error itself
+const PIPE_ERROR_EXIT_GRACE = 1_000
 
 /** @experimental */
 export class ForksPoolWorker implements PoolWorker {
@@ -20,6 +24,9 @@ export class ForksPoolWorker implements PoolWorker {
   private stdout: NodeJS.WriteStream | Writable
   private stderr: NodeJS.WriteStream | Writable
 
+  private _errorEmitter = new EventEmitter<{ error: [Error] }>()
+  private _pipeErrorTimer: ReturnType<typeof setTimeout> | undefined
+
   constructor(options: PoolOptions) {
     this.execArgv = options.execArgv
     this.env = options.env
@@ -31,11 +38,21 @@ export class ForksPoolWorker implements PoolWorker {
   }
 
   on(event: string, callback: (...args: any[]) => void): void {
-    this.fork.on(event, callback)
+    if (event === 'error') {
+      this._errorEmitter.on('error', callback)
+    }
+    else {
+      this.fork.on(event, callback)
+    }
   }
 
   off(event: string, callback: (...args: any[]) => void): void {
-    this.fork.off(event, callback)
+    if (event === 'error') {
+      this._errorEmitter.off('error', callback)
+    }
+    else {
+      this.fork.off(event, callback)
+    }
   }
 
   send(message: WorkerRequest): void {
@@ -50,6 +67,8 @@ export class ForksPoolWorker implements PoolWorker {
       serialization: 'advanced',
     })
 
+    this._fork.on('error', this.emitError)
+
     // `end: false`: the logger streams are shared by every worker, so one
     // ending worker stream must not end them for everyone else
     if (this._fork.stdout) {
@@ -108,6 +127,40 @@ export class ForksPoolWorker implements PoolWorker {
     return data
   }
 
+  private emitError = (error: Error): void => {
+    // A write into a dying child process fails with EPIPE (or a closed IPC
+    // channel) and can be observed before the process's 'exit' event,
+    // especially on macOS. The exit event knows the exit code, the signal and
+    // the affected test files, so hold the write error and let the 'exit'
+    // listeners report instead. The timer covers a broken channel whose
+    // process never exits; a process that exited while the error was held was
+    // already reported through the exit event, and a process whose listeners
+    // were detached is being shut down deliberately — drop the error in both
+    // cases.
+    const code = (error as NodeJS.ErrnoException).code
+    if (code === 'EPIPE' || code === 'ERR_IPC_CHANNEL_CLOSED') {
+      if (this._pipeErrorTimer) {
+        return
+      }
+      this._pipeErrorTimer = setTimeout(() => {
+        this._pipeErrorTimer = undefined
+        const fork = this._fork
+        if (
+          fork
+          && fork.exitCode == null
+          && fork.signalCode == null
+          && this._errorEmitter.listenerCount('error')
+        ) {
+          this._errorEmitter.emit('error', error)
+        }
+      }, PIPE_ERROR_EXIT_GRACE)
+      this._pipeErrorTimer.unref()
+      return
+    }
+
+    this._errorEmitter.emit('error', error)
+  }
+
   private get fork() {
     if (!this._fork) {
       throw new Error(`The child process was torn down or never initialized. This is a bug in Vitest.`)