fix: don't call fs.watch if watch is disabled

packages/vite/src/node/server/index.ts

@@ -52,6 +52,7 @@ import type { Logger } from '../logger'
 import { printServerUrls } from '../logger'
 import { warnFutureDeprecation } from '../deprecations'
 import {
+  createNoopWatcher,
   getResolvedOutDirs,
   resolveChokidarOptions,
   resolveEmptyOutDir,
@@ -467,26 +468,22 @@ export async function _createServer(
     setClientErrorHandler(httpServer, config.logger)
   }
 
-  const watcher = chokidar.watch(
-    // config file dependencies and env file might be outside of root
-    [
-      root,
-      ...config.configFileDependencies,
-      ...getEnvFilesForMode(config.mode, config.envDir),
-      // Watch the public directory explicitly because it might be outside
-      // of the root directory.
-      ...(publicDir && publicFiles ? [publicDir] : []),
-    ],
-    resolvedWatchOptions,
-  )
-  // If watch is turned off, patch `.add()` as a noop to prevent programmatically
-  // watching additional files and to keep it fast.
-  // eslint-disable-next-line eqeqeq -- null means disabled
-  if (serverConfig.watch === null) {
-    watcher.add = function () {
-      return this
-    }
-  }
+  const watcher =
+    // eslint-disable-next-line eqeqeq -- null means disabled
+    serverConfig.watch === null
+      ? createNoopWatcher()
+      : chokidar.watch(
+          // config file dependencies and env file might be outside of root
+          [
+            root,
+            ...config.configFileDependencies,
+            ...getEnvFilesForMode(config.mode, config.envDir),
+            // Watch the public directory explicitly because it might be outside
+            // of the root directory.
+            ...(publicDir && publicFiles ? [publicDir] : []),
+          ],
+          resolvedWatchOptions,
+        )
 
   const environments: Record<string, DevEnvironment> = {}
 

packages/vite/src/node/watch.ts

@@ -1,5 +1,10 @@
 import path from 'node:path'
-import type { WatchOptions } from 'dep-types/chokidar'
+import EventEmitter from 'node:events'
+import type {
+  FSWInstanceOptions,
+  FSWatcher,
+  WatchOptions,
+} from 'dep-types/chokidar'
 import picomatch from 'picomatch'
 import type { OutputOptions } from 'rollup'
 import colors from 'picocolors'
@@ -95,3 +100,39 @@ export function resolveChokidarOptions(
 
   return resolvedWatchOptions
 }
+
+class NoopWatcher extends EventEmitter implements FSWatcher {
+  closed = true
+  options: FSWInstanceOptions = {
+    persistent: false,
+    ignoreInitial: false,
+    followSymlinks: false,
+    usePolling: false,
+    interval: 0,
+    binaryInterval: 0,
+    ignorePermissionErrors: false,
+    atomic: false,
+    ignored: [],
+    awaitWriteFinish: false,
+  }
+
+  add() {
+    return this
+  }
+  unwatch() {
+    return this
+  }
+  async close() {
+    // noop
+  }
+  getWatched(): Record<string, string[]> {
+    return {}
+  }
+  emitWithAll() {
+    // noop
+  }
+}
+
+export function createNoopWatcher(): NoopWatcher {
+  return new NoopWatcher()
+}