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

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 { resolveMock } from './resolveMock'
@@ -66,6 +67,10 @@ 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) {

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')
+  }
+})