fix(browser): print correct stack trace for unhandled errors

packages/browser/src/client/public/error-catcher.js

@@ -1,10 +1,5 @@
 import { channel, client } from '@vitest/browser/client'
 
-function on(event, listener) {
-  window.addEventListener(event, listener)
-  return () => window.removeEventListener(event, listener)
-}
-
 function serializeError(unhandledError) {
   if (typeof unhandledError !== 'object' || !unhandledError) {
     return {
@@ -19,41 +14,40 @@ function serializeError(unhandledError) {
   }
 }
 
-function catchWindowErrors(cb) {
+function catchWindowErrors(errorEvent, prop, cb) {
   let userErrorListenerCount = 0
   function throwUnhandlerError(e) {
-    if (userErrorListenerCount === 0 && e.error != null) {
+    if (userErrorListenerCount === 0 && e[prop] != null) {
       cb(e)
     }
     else {
-      console.error(e.error)
+      console.error(e[prop])
     }
   }
   const addEventListener = window.addEventListener.bind(window)
   const removeEventListener = window.removeEventListener.bind(window)
-  window.addEventListener('error', throwUnhandlerError)
+  window.addEventListener(errorEvent, throwUnhandlerError)
   window.addEventListener = function (...args) {
-    if (args[0] === 'error') {
+    if (args[0] === errorEvent) {
       userErrorListenerCount++
     }
     return addEventListener.apply(this, args)
   }
   window.removeEventListener = function (...args) {
-    if (args[0] === 'error' && userErrorListenerCount) {
+    if (args[0] === errorEvent && userErrorListenerCount) {
       userErrorListenerCount--
     }
     return removeEventListener.apply(this, args)
   }
   return function clearErrorHandlers() {
-    window.removeEventListener('error', throwUnhandlerError)
+    window.removeEventListener(errorEvent, throwUnhandlerError)
   }
 }
 
 function registerUnexpectedErrors() {
-  catchWindowErrors(event =>
-    reportUnexpectedError('Error', event.error),
-  )
-  on('unhandledrejection', event =>
+  catchWindowErrors('error', 'error', event =>
+    reportUnexpectedError('Error', event.error))
+  catchWindowErrors('unhandledrejection', 'reason', event =>
     reportUnexpectedError('Unhandled Rejection', event.reason))
 }
 

packages/browser/src/node/rpc.ts

@@ -6,6 +6,7 @@ import type { WebSocket } from 'ws'
 import { WebSocketServer } from 'ws'
 import type { BrowserCommandContext } from 'vitest/node'
 import { createDebugger, isFileServingAllowed } from 'vitest/node'
+import type { ErrorWithDiff } from 'vitest'
 import type { WebSocketBrowserEvents, WebSocketBrowserHandlers } from './types'
 import type { BrowserServer } from './server'
 import { cleanUrl, resolveMock } from './resolveMock'
@@ -67,6 +68,10 @@ export function setupBrowserRpc(
     const rpc = createBirpc<WebSocketBrowserEvents, WebSocketBrowserHandlers>(
       {
         async onUnhandledError(error, type) {
+          if (error && typeof error === 'object') {
+            const _error = error as ErrorWithDiff
+            _error.stacks = server.parseErrorStacktrace(_error)
+          }
           ctx.state.catchError(error, type)
         },
         async onCollected(files) {

packages/browser/src/node/server.ts

@@ -87,7 +87,7 @@ export class BrowserServer implements IBrowserServer {
       resolve(distRoot, 'client/esm-client-injector.js'),
       'utf8',
     ).then(js => (this.injectorJs = js))
-    this.errorCatcherPath = resolve(distRoot, 'client/error-catcher.js')
+    this.errorCatcherPath = join('/@fs/', resolve(distRoot, 'client/error-catcher.js'))
     this.stateJs = readFile(
       resolve(distRoot, 'state.js'),
       'utf-8',

test/browser/fixtures/unhandled/throw-unhandled-error.test.ts

@@ -0,0 +1,11 @@
+import { test } from 'vitest';
+
+interface _Unused {
+  _fake: never
+}
+
+test('unhandled exception', () => {
+  ;(async () => {
+    throw new Error('custom_unhandled_error')
+  })()
+})

test/browser/fixtures/unhandled/vitest.config.ts

@@ -0,0 +1,18 @@
+import { fileURLToPath } from 'node:url'
+import { defineConfig } from 'vitest/config'
+
+const provider = process.env.PROVIDER || 'playwright'
+const name =
+  process.env.BROWSER || (provider === 'playwright' ? 'chromium' : 'chrome')
+
+export default defineConfig({
+  cacheDir: fileURLToPath(new URL("./node_modules/.vite", import.meta.url)),
+  test: {
+    browser: {
+      enabled: true,
+      provider,
+      name,
+      headless: true,
+    },
+  },
+})

test/browser/specs/unhandled.test.ts

@@ -0,0 +1,15 @@
+import { expect, test } from 'vitest'
+import { runBrowserTests } from './utils'
+
+test('prints correct unhandled error stack', async () => {
+  const { stderr, browser } = await runBrowserTests({
+    root: './fixtures/unhandled',
+  })
+
+  if (browser === 'webkit') {
+    expect(stderr).toContain('throw-unhandled-error.test.ts:9:20')
+  }
+  else {
+    expect(stderr).toContain('throw-unhandled-error.test.ts:9:10')
+  }
+})