fix(hmr): make watcher ignore build.outDir (#15326)

Author: nozomuikuta

docs/config/server-options.md

@@ -202,7 +202,7 @@ export default defineConfig({
 
 File system watcher options to pass on to [chokidar](https://github.com/paulmillr/chokidar#api).
 
-The Vite server watcher watches the `root` and skips the `.git/` and `node_modules/` directories by default. When updating a watched file, Vite will apply HMR and update the page only if needed.
+The Vite server watcher watches the `root` and skips the `.git/`, `node_modules/`, and Vite's `cacheDir` and `build.outDir` directories by default. When updating a watched file, Vite will apply HMR and update the page only if needed.
 
 If set to `null`, no files will be watched. `server.watcher` will provide a compatible event emitter, but calling `add` or `unwatch` will have no effect.
 

packages/vite/src/node/watch.ts

@@ -1,4 +1,5 @@
 import { EventEmitter } from 'node:events'
+import path from 'node:path'
 import glob from 'fast-glob'
 import type { FSWatcher, WatchOptions } from 'dep-types/chokidar'
 import { arraify } from './utils'
@@ -16,6 +17,7 @@ export function resolveChokidarOptions(
       '**/node_modules/**',
       '**/test-results/**', // Playwright
       glob.escapePath(config.cacheDir) + '/**',
+      glob.escapePath(path.resolve(config.root, config.build.outDir)) + '/**',
       ...arraify(ignored),
     ],
     ignoreInitial: true,