fix(core): close stale watcher after shortcut restart

e2e/cases/cli/shortcut-restart-watcher/dev.js

@@ -0,0 +1,6 @@
+import { runCLI } from '@rsbuild/core';
+
+process.stdin.isTTY = true;
+delete process.env.CI;
+
+runCLI({ argv: ['node', 'rsbuild', 'dev'] });

e2e/cases/cli/shortcut-restart-watcher/index.test.ts

@@ -0,0 +1,38 @@
+import fs from 'node:fs';
+import path from 'node:path';
+import { expect, test } from '@e2e/helper';
+import { getRandomPort } from '@rstackjs/test-utils';
+
+const watchedFile = path.join(import.meta.dirname, 'test-temp-watch.txt');
+const restartLog = 'restarting server as test-temp-watch.txt changed';
+
+test.beforeEach(() => {
+  fs.writeFileSync(watchedFile, '1');
+});
+
+test.afterAll(() => {
+  fs.rmSync(watchedFile, { force: true });
+});
+
+test('should close the old watcher after a shortcut restart', async ({ exec, logHelper }) => {
+  const port = await getRandomPort();
+  const { childProcess } = exec('node ./dev.js', {
+    env: {
+      PORT: String(port),
+    },
+  });
+  const { clearLogs, expectBuildEnd, expectLog, logs } = logHelper;
+
+  await expectBuildEnd();
+  clearLogs();
+  childProcess.stdin?.write('r\n');
+  await expectLog('restarting server');
+  await expectBuildEnd();
+
+  clearLogs();
+  fs.writeFileSync(watchedFile, '2');
+  await expectLog(restartLog);
+  await expectBuildEnd();
+
+  expect(logs.filter((log) => log.includes(restartLog))).toHaveLength(1);
+});

e2e/cases/cli/shortcut-restart-watcher/rsbuild.config.mjs

@@ -0,0 +1,11 @@
+export default {
+  dev: {
+    watchFiles: {
+      paths: './test-temp-watch.txt',
+      type: 'restart',
+    },
+  },
+  server: {
+    port: Number(process.env.PORT),
+  },
+};

e2e/cases/cli/shortcut-restart-watcher/src/index.js

@@ -0,0 +1 @@
+console.log('shortcut restart watcher');

packages/core/src/build.ts

@@ -65,6 +65,9 @@ export const build = async (
 
   let closingPromise: Promise<void> | undefined;
   let unregisterRestart: (() => void) | undefined;
+
+  // Keep the restart watcher active when closing build resources,
+  // so failed restarts can be retried.
   const closeBuild = () => {
     closingPromise ||= (async () => {
       unregisterRestart?.();
@@ -77,7 +80,6 @@ export const build = async (
 
   let restartWatcher: ReturnType<typeof watchFilesForRestart>;
   if (watch) {
-    // Only close build resources before restart; keep the watcher alive for retries.
     unregisterRestart = context.restartManager.registerCleanup(closeBuild);
     restartWatcher = watchFilesForRestart({
       watchFiles: context.normalizedConfig!.dev.watchFiles,
@@ -86,6 +88,7 @@ export const build = async (
     });
   }
 
+  // Fully close the build and its restart watcher.
   const close = async () => {
     await restartWatcher?.close();
     await closeBuild();

packages/core/src/server/devServer.ts

@@ -203,6 +203,8 @@ export async function createDevServer<
   let closingPromise: Promise<void> | undefined;
   let unregisterRestart: (() => void) | undefined;
 
+  // Keep the restart watcher active when closing server resources,
+  // so failed restarts can be retried.
   const closeServerResources = () => {
     if (!closingPromise) {
       unregisterRestart?.();
@@ -217,11 +219,28 @@ export async function createDevServer<
     return closingPromise;
   };
 
+  // Fully close the server and its restart watcher.
   const closeServer = async () => {
     await state.restartWatcher?.close();
     await closeServerResources();
   };
 
+  // Request a manual restart and close the old watcher only after it succeeds.
+  const restartServer = async () => {
+    const restarted = await requestRestart({
+      action: 'dev',
+      clear: false,
+      logger,
+      restartManager: context.restartManager,
+    });
+
+    if (restarted) {
+      await state.restartWatcher?.close();
+    }
+
+    return restarted;
+  };
+
   if (!middlewareMode) {
     registerCleanup(closeServer);
   }
@@ -237,15 +256,7 @@ export async function createDevServer<
         openPage,
         closeServer,
         printUrls,
-        restartServer: context.restartManager.canRestart
-          ? () =>
-              requestRestart({
-                action: 'dev',
-                clear: false,
-                logger,
-                restartManager: context.restartManager,
-              })
-          : undefined,
+        restartServer: context.restartManager.canRestart ? restartServer : undefined,
         help: shortcutsOptions.help,
         customShortcuts: shortcutsOptions.custom,
         logger,
@@ -440,7 +451,6 @@ export async function createDevServer<
   // start watching
   state.buildManager?.watch();
 
-  // Only close server resources before restart; keep the watcher alive for retries.
   unregisterRestart = context.restartManager.registerCleanup(closeServerResources);
   state.restartWatcher = watchFilesForRestart({
     watchFiles: config.dev.watchFiles,