feat: forward browser console logs and errors to dev server terminal (#20916)

Co-authored-by: Claude <noreply@anthropic.com>

Author: hi-ogawa

docs/config/server-options.md

@@ -224,6 +224,44 @@ The error that appears in the Browser when the fallback happens can be ignored.
 
 :::
 
+## server.forwardConsole
+
+- **Type:** `boolean | { unhandledErrors?: boolean, logLevels?: ('error' | 'warn' | 'info' | 'log' | 'debug')[] }`
+- **Default:** auto (`true` when an AI coding agent is detected based on [`@vercel/detect-agent`](https://www.npmjs.com/package/@vercel/detect-agent), otherwise `false`)
+
+Forward browser runtime events to the Vite server console during development.
+
+- `true` enables forwarding unhandled errors and `console.error` / `console.warn` logs.
+- `unhandledErrors` controls forwarding uncaught exceptions and unhandled promise rejections.
+- `logLevels` controls which `console.*` calls are forwarded.
+
+For example:
+
+```js
+export default defineConfig({
+  server: {
+    forwardConsole: {
+      unhandledErrors: true,
+      logLevels: ['warn', 'error'],
+    },
+  },
+})
+```
+
+When unhandled errors are forwarded, they are logged in the server terminal with enhanced formatting, for example:
+
+```log
+1:18:38 AM [vite] (client) [Unhandled error] Error: this is test error
+ > testError src/main.ts:20:8
+     18|
+     19| function testError() {
+     20|   throw new Error('this is test error')
+       |        ^
+     21| }
+     22|
+ > HTMLButtonElement.<anonymous> src/main.ts:6:2
+```
+
 ## server.warmup
 
 - **Type:** `{ clientFiles?: string[], ssrFiles?: string[] }`

packages/vite/LICENSE.md

@@ -25,7 +25,7 @@ SOFTWARE.
 
 # Licenses of bundled dependencies
 The published Vite artifact additionally contains code with the following licenses:
-BSD-2-Clause, CC0-1.0, ISC, MIT
+Apache-2.0, BSD-2-Clause, CC0-1.0, ISC, MIT
 
 # Bundled dependencies:
 ## @jridgewell/gen-mapping, @jridgewell/remapping, @jridgewell/sourcemap-codec, @jridgewell/trace-mapping
@@ -132,6 +132,243 @@ Repository: https://github.com/rollup/plugins
 
 ---------------------------------------
 
+## @vercel/detect-agent
+License: Apache-2.0
+By: Vercel
+Repository: https://github.com/vercel/vercel
+
+> Apache License
+>                            Version 2.0, January 2004
+>                         http://www.apache.org/licenses/
+> 
+>    TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+> 
+>    1. Definitions.
+> 
+>       "License" shall mean the terms and conditions for use, reproduction,
+>       and distribution as defined by Sections 1 through 9 of this document.
+> 
+>       "Licensor" shall mean the copyright owner or entity authorized by
+>       the copyright owner that is granting the License.
+> 
+>       "Legal Entity" shall mean the union of the acting entity and all
+>       other entities that control, are controlled by, or are under common
+>       control with that entity. For the purposes of this definition,
+>       "control" means (i) the power, direct or indirect, to cause the
+>       direction or management of such entity, whether by contract or
+>       otherwise, or (ii) ownership of fifty percent (50%) or more of the
+>       outstanding shares, or (iii) beneficial ownership of such entity.
+> 
+>       "You" (or "Your") shall mean an individual or Legal Entity
+>       exercising permissions granted by this License.
+> 
+>       "Source" form shall mean the preferred form for making modifications,
+>       including but not limited to software source code, documentation
+>       source, and configuration files.
+> 
+>       "Object" form shall mean any form resulting from mechanical
+>       transformation or translation of a Source form, including but
+>       not limited to compiled object code, generated documentation,
+>       and conversions to other media types.
+> 
+>       "Work" shall mean the work of authorship, whether in Source or
+>       Object form, made available under the License, as indicated by a
+>       copyright notice that is included in or attached to the work
+>       (an example is provided in the Appendix below).
+> 
+>       "Derivative Works" shall mean any work, whether in Source or Object
+>       form, that is based on (or derived from) the Work and for which the
+>       editorial revisions, annotations, elaborations, or other modifications
+>       represent, as a whole, an original work of authorship. For the purposes
+>       of this License, Derivative Works shall not include works that remain
+>       separable from, or merely link (or bind by name) to the interfaces of,
+>       the Work and Derivative Works thereof.
+> 
+>       "Contribution" shall mean any work of authorship, including
+>       the original version of the Work and any modifications or additions
+>       to that Work or Derivative Works thereof, that is intentionally
+>       submitted to Licensor for inclusion in the Work by the copyright owner
+>       or by an individual or Legal Entity authorized to submit on behalf of
+>       the copyright owner. For the purposes of this definition, "submitted"
+>       means any form of electronic, verbal, or written communication sent
+>       to the Licensor or its representatives, including but not limited to
+>       communication on electronic mailing lists, source code control systems,
+>       and issue tracking systems that are managed by, or on behalf of, the
+>       Licensor for the purpose of discussing and improving the Work, but
+>       excluding communication that is conspicuously marked or otherwise
+>       designated in writing by the copyright owner as "Not a Contribution."
+> 
+>       "Contributor" shall mean Licensor and any individual or Legal Entity
+>       on behalf of whom a Contribution has been received by Licensor and
+>       subsequently incorporated within the Work.
+> 
+>    2. Grant of Copyright License. Subject to the terms and conditions of
+>       this License, each Contributor hereby grants to You a perpetual,
+>       worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+>       copyright license to reproduce, prepare Derivative Works of,
+>       publicly display, publicly perform, sublicense, and distribute the
+>       Work and such Derivative Works in Source or Object form.
+> 
+>    3. Grant of Patent License. Subject to the terms and conditions of
+>       this License, each Contributor hereby grants to You a perpetual,
+>       worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+>       (except as stated in this section) patent license to make, have made,
+>       use, offer to sell, sell, import, and otherwise transfer the Work,
+>       where such license applies only to those patent claims licensable
+>       by such Contributor that are necessarily infringed by their
+>       Contribution(s) alone or by combination of their Contribution(s)
+>       with the Work to which such Contribution(s) was submitted. If You
+>       institute patent litigation against any entity (including a
+>       cross-claim or counterclaim in a lawsuit) alleging that the Work
+>       or a Contribution incorporated within the Work constitutes direct
+>       or contributory patent infringement, then any patent licenses
+>       granted to You under this License for that Work shall terminate
+>       as of the date such litigation is filed.
+> 
+>    4. Redistribution. You may reproduce and distribute copies of the
+>       Work or Derivative Works thereof in any medium, with or without
+>       modifications, and in Source or Object form, provided that You
+>       meet the following conditions:
+> 
+>       (a) You must give any other recipients of the Work or
+>           Derivative Works a copy of this License; and
+> 
+>       (b) You must cause any modified files to carry prominent notices
+>           stating that You changed the files; and
+> 
+>       (c) You must retain, in the Source form of any Derivative Works
+>           that You distribute, all copyright, patent, trademark, and
+>           attribution notices from the Source form of the Work,
+>           excluding those notices that do not pertain to any part of
+>           the Derivative Works; and
+> 
+>       (d) If the Work includes a "NOTICE" text file as part of its
+>           distribution, then any Derivative Works that You distribute must
+>           include a readable copy of the attribution notices contained
+>           within such NOTICE file, excluding those notices that do not
+>           pertain to any part of the Derivative Works, in at least one
+>           of the following places: within a NOTICE text file distributed
+>           as part of the Derivative Works; within the Source form or
+>           documentation, if provided along with the Derivative Works; or,
+>           within a display generated by the Derivative Works, if and
+>           wherever such third-party notices normally appear. The contents
+>           of the NOTICE file are for informational purposes only and
+>           do not modify the License. You may add Your own attribution
+>           notices within Derivative Works that You distribute, alongside
+>           or as an addendum to the NOTICE text from the Work, provided
+>           that such additional attribution notices cannot be construed
+>           as modifying the License.
+> 
+>       You may add Your own copyright statement to Your modifications and
+>       may provide additional or different license terms and conditions
+>       for use, reproduction, or distribution of Your modifications, or
+>       for any such Derivative Works as a whole, provided Your use,
+>       reproduction, and distribution of the Work otherwise complies with
+>       the conditions stated in this License.
+> 
+>    5. Submission of Contributions. Unless You explicitly state otherwise,
+>       any Contribution intentionally submitted for inclusion in the Work
+>       by You to the Licensor shall be under the terms and conditions of
+>       this License, without any additional terms or conditions.
+>       Notwithstanding the above, nothing herein shall supersede or modify
+>       the terms of any separate license agreement you may have executed
+>       with Licensor regarding such Contributions.
+> 
+>    6. Trademarks. This License does not grant permission to use the trade
+>       names, trademarks, service marks, or product names of the Licensor,
+>       except as required for reasonable and customary use in describing the
+>       origin of the Work and reproducing the content of the NOTICE file.
+> 
+>    7. Disclaimer of Warranty. Unless required by applicable law or
+>       agreed to in writing, Licensor provides the Work (and each
+>       Contributor provides its Contributions) on an "AS IS" BASIS,
+>       WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+>       implied, including, without limitation, any warranties or conditions
+>       of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+>       PARTICULAR PURPOSE. You are solely responsible for determining the
+>       appropriateness of using or redistributing the Work and assume any
+>       risks associated with Your exercise of permissions under this License.
+> 
+>    8. Limitation of Liability. In no event and under no legal theory,
+>       whether in tort (including negligence), contract, or otherwise,
+>       unless required by applicable law (such as deliberate and grossly
+>       negligent acts) or agreed to in writing, shall any Contributor be
+>       liable to You for damages, including any direct, indirect, special,
+>       incidental, or consequential damages of any character arising as a
+>       result of this License or out of the use or inability to use the
+>       Work (including but not limited to damages for loss of goodwill,
+>       work stoppage, computer failure or malfunction, or any and all
+>       other commercial damages or losses), even if such Contributor
+>       has been advised of the possibility of such damages.
+> 
+>    9. Accepting Warranty or Additional Liability. While redistributing
+>       the Work or Derivative Works thereof, You may choose to offer,
+>       and charge a fee for, acceptance of support, warranty, indemnity,
+>       or other liability obligations and/or rights consistent with this
+>       License. However, in accepting such obligations, You may act only
+>       on Your own behalf and on Your sole responsibility, not on behalf
+>       of any other Contributor, and only if You agree to indemnify,
+>       defend, and hold each Contributor harmless for any liability
+>       incurred by, or claims asserted against, such Contributor by reason
+>       of your accepting any such warranty or additional liability.
+> 
+>    END OF TERMS AND CONDITIONS
+> 
+>    APPENDIX: How to apply the Apache License to your work.
+> 
+>       To apply the Apache License to your work, attach the following
+>       boilerplate notice, with the fields enclosed by brackets "[]"
+>       replaced with your own identifying information. (Don't include
+>       the brackets!)  The text should be enclosed in the appropriate
+>       comment syntax for the file format. We also recommend that a
+>       file or class name and description of purpose be included on the
+>       same "printed page" as the copyright notice for easier
+>       identification within third-party archives.
+> 
+>    Copyright 2017 Vercel, Inc.
+> 
+>    Licensed under the Apache License, Version 2.0 (the "License");
+>    you may not use this file except in compliance with the License.
+>    You may obtain a copy of the License at
+> 
+>        http://www.apache.org/licenses/LICENSE-2.0
+> 
+>    Unless required by applicable law or agreed to in writing, software
+>    distributed under the License is distributed on an "AS IS" BASIS,
+>    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+>    See the License for the specific language governing permissions and
+>    limitations under the License.
+
+---------------------------------------
+
+## @vitest/utils
+License: MIT
+Repository: https://github.com/vitest-dev/vitest
+
+> MIT License
+> 
+> Copyright (c) 2021-Present VoidZero Inc. and Vitest contributors
+> 
+> Permission is hereby granted, free of charge, to any person obtaining a copy
+> of this software and associated documentation files (the "Software"), to deal
+> in the Software without restriction, including without limitation the rights
+> to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+> copies of the Software, and to permit persons to whom the Software is
+> furnished to do so, subject to the following conditions:
+> 
+> The above copyright notice and this permission notice shall be included in all
+> copies or substantial portions of the Software.
+> 
+> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+> IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+> FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+> AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+> LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+> OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+> SOFTWARE.
+
+---------------------------------------
+
 ## anymatch
 License: ISC
 By: Elan Shanker

packages/vite/package.json

@@ -91,8 +91,10 @@
     "@rollup/plugin-alias": "^6.0.0",
     "@rollup/plugin-dynamic-import-vars": "2.1.4",
     "@rollup/pluginutils": "^5.3.0",
+    "@vercel/detect-agent": "^1.1.0",
     "@types/escape-html": "^1.0.4",
     "@types/pnpapi": "^0.0.5",
+    "@vitest/utils": "4.1.0-beta.5",
     "@vitejs/devtools": "^0.0.0-alpha.32",
     "artichokie": "^0.4.2",
     "baseline-browser-mapping": "^2.10.0",

packages/vite/src/client/client.ts

@@ -10,6 +10,7 @@ import {
   normalizeModuleRunnerTransport,
 } from '../shared/moduleRunnerTransport'
 import { createHMRHandler } from '../shared/hmrHandler'
+import { setupForwardConsoleHandler } from '../shared/forwardConsole'
 import { ErrorOverlay, cspNonce, overlayId } from './overlay'
 import '@vite/env'
 
@@ -24,6 +25,7 @@ declare const __HMR_BASE__: string
 declare const __HMR_TIMEOUT__: number
 declare const __HMR_ENABLE_OVERLAY__: boolean
 declare const __WS_TOKEN__: string
+declare const __SERVER_FORWARD_CONSOLE__: any
 declare const __BUNDLED_DEV__: boolean
 
 console.debug('[vite] connecting...')
@@ -43,6 +45,7 @@ const base = __BASE__ || '/'
 const hmrTimeout = __HMR_TIMEOUT__
 const wsToken = __WS_TOKEN__
 const isBundleMode = __BUNDLED_DEV__
+const forwardConsole = __SERVER_FORWARD_CONSOLE__
 
 const transport = normalizeModuleRunnerTransport(
   (() => {
@@ -196,6 +199,8 @@ const hmrClient = new HMRClient(
 )
 transport.connect!(createHMRHandler(handleMessage))
 
+setupForwardConsoleHandler(transport, forwardConsole)
+
 async function handleMessage(payload: HotPayload) {
   switch (payload.type) {
     case 'connected':

packages/vite/src/node/config.ts

@@ -1698,7 +1698,7 @@ export async function resolveConfig(
         )
       : ''
 
-  const server = resolveServerOptions(resolvedRoot, config.server, logger)
+  const server = await resolveServerOptions(resolvedRoot, config.server, logger)
 
   const builder = resolveBuilderOptions(config.builder)
 

packages/vite/src/node/plugins/clientInjections.ts

@@ -112,6 +112,9 @@ async function createClientConfigValueReplacer(
   const hmrEnableOverlayReplacement = escapeReplacement(overlay)
   const hmrConfigNameReplacement = escapeReplacement(hmrConfigName)
   const wsTokenReplacement = escapeReplacement(config.webSocketToken)
+  const serverForwardConsoleReplacement = escapeReplacement(
+    config.server.forwardConsole as any,
+  )
   const bundleDevReplacement = escapeReplacement(
     config.experimental.bundledDev || false,
   )
@@ -130,6 +133,7 @@ async function createClientConfigValueReplacer(
       .replace(`__HMR_ENABLE_OVERLAY__`, hmrEnableOverlayReplacement)
       .replace(`__HMR_CONFIG_NAME__`, hmrConfigNameReplacement)
       .replace(`__WS_TOKEN__`, wsTokenReplacement)
+      .replace(`__SERVER_FORWARD_CONSOLE__`, serverForwardConsoleReplacement)
       .replaceAll(`__BUNDLED_DEV__`, bundleDevReplacement)
 }