fix: harden Windows single-instance startup (#498)

electron/main/index.ts

@@ -21,6 +21,12 @@ import { autoInstallCliIfNeeded, generateCompletionCache, installCompletionToPro
 import { isQuitting, setQuitting } from './app-state';
 import { applyProxySettings } from './proxy';
 import { syncLaunchAtStartupSettingFromStore } from './launch-at-startup';
+import {
+  clearPendingSecondInstanceFocus,
+  consumeMainWindowReady,
+  createMainWindowFocusState,
+  requestSecondInstanceFocus,
+} from './main-window-focus';
 import { getSetting } from '../utils/store';
 import { ensureBuiltinSkillsInstalled, ensurePreinstalledSkillsInstalled } from '../utils/skill-config';
 import { startHostApiServer } from '../api/server';
@@ -30,6 +36,8 @@ import { browserOAuthManager } from '../utils/browser-oauth';
 import { whatsAppLoginManager } from '../utils/whatsapp-login';
 import { syncAllProviderAuthToRuntime } from '../services/providers/provider-runtime-sync';
 
+const WINDOWS_APP_USER_MODEL_ID = 'app.clawx.desktop';
+
 // Disable GPU hardware acceleration globally for maximum stability across
 // all GPU configurations (no GPU, integrated, discrete).
 //
@@ -58,17 +66,19 @@ if (process.platform === 'linux') {
 // Without this, two instances each spawn their own gateway process on the
 // same port, then each treats the other's gateway as "orphaned" and kills
 // it — creating an infinite kill/restart loop on Windows.
+// The losing process must exit immediately so it never reaches Gateway startup.
 const gotTheLock = app.requestSingleInstanceLock();
 if (!gotTheLock) {
-  app.quit();
+  app.exit(0);
 }
 
 // Global references
 let mainWindow: BrowserWindow | null = null;
-const gatewayManager = new GatewayManager();
-const clawHubService = new ClawHubService();
-const hostEventBus = new HostEventBus();
+let gatewayManager!: GatewayManager;
+let clawHubService!: ClawHubService;
+let hostEventBus!: HostEventBus;
 let hostApiServer: Server | null = null;
+const mainWindowFocusState = createMainWindowFocusState();
 
 /**
  * Resolve the icons directory path (works in both dev and packaged mode)
@@ -122,11 +132,6 @@ function createWindow(): BrowserWindow {
     show: false,
   });
 
-  // Show window when ready to prevent visual flash
-  win.once('ready-to-show', () => {
-    win.show();
-  });
-
   // Handle external links
   win.webContents.setWindowOpenHandler(({ url }) => {
     shell.openExternal(url);
@@ -144,6 +149,62 @@ function createWindow(): BrowserWindow {
   return win;
 }
 
+function focusWindow(win: BrowserWindow): void {
+  if (win.isDestroyed()) {
+    return;
+  }
+
+  if (win.isMinimized()) {
+    win.restore();
+  }
+
+  win.show();
+  win.focus();
+}
+
+function focusMainWindow(): void {
+  if (!mainWindow || mainWindow.isDestroyed()) {
+    return;
+  }
+
+  clearPendingSecondInstanceFocus(mainWindowFocusState);
+  focusWindow(mainWindow);
+}
+
+function createMainWindow(): BrowserWindow {
+  const win = createWindow();
+
+  win.once('ready-to-show', () => {
+    if (mainWindow !== win) {
+      return;
+    }
+
+    const action = consumeMainWindowReady(mainWindowFocusState);
+    if (action === 'focus') {
+      focusWindow(win);
+      return;
+    }
+
+    win.show();
+  });
+
+  win.on('close', (event) => {
+    if (!isQuitting()) {
+      event.preventDefault();
+      win.hide();
+    }
+  });
+
+  win.on('closed', () => {
+    if (mainWindow === win) {
+      mainWindow = null;
+    }
+  });
+
+  mainWindow = win;
+  return win;
+}
+
 /**
  * Initialize the application
  */
@@ -169,10 +230,10 @@ async function initialize(): Promise<void> {
   createMenu();
 
   // Create the main window
-  mainWindow = createWindow();
+  const window = createMainWindow();
 
   // Create system tray
-  createTray(mainWindow);
+  createTray(window);
 
   // Override security headers ONLY for the OpenClaw Gateway Control UI.
   // The URL filter ensures this callback only fires for gateway requests,
@@ -198,33 +259,21 @@ async function initialize(): Promise<void> {
   );
 
   // Register IPC handlers
-  registerIpcHandlers(gatewayManager, clawHubService, mainWindow);
+  registerIpcHandlers(gatewayManager, clawHubService, window);
 
   hostApiServer = startHostApiServer({
     gatewayManager,
     clawHubService,
     eventBus: hostEventBus,
-    mainWindow,
+    mainWindow: window,
   });
 
   // Register update handlers
-  registerUpdateHandlers(appUpdater, mainWindow);
+  registerUpdateHandlers(appUpdater, window);
 
   // Note: Auto-check for updates is driven by the renderer (update store init)
   // so it respects the user's "Auto-check for updates" setting.
 
-  // Minimize to tray on close instead of quitting (macOS & Windows)
-  mainWindow.on('close', (event) => {
-    if (!isQuitting()) {
-      event.preventDefault();
-      mainWindow?.hide();
-    }
-  });
-
-  mainWindow.on('closed', () => {
-    mainWindow = null;
-  });
-
   // Repair any bootstrap files that only contain ClawX markers (no OpenClaw
   // template content). This fixes a race condition where ensureClawXContext()
   // previously created the file before the gateway could seed the full template.
@@ -354,50 +403,66 @@ async function initialize(): Promise<void> {
   });
 }
 
-// When a second instance is launched, focus the existing window instead.
-app.on('second-instance', () => {
-  if (mainWindow) {
-    if (mainWindow.isMinimized()) mainWindow.restore();
-    mainWindow.show();
-    mainWindow.focus();
+if (gotTheLock) {
+  if (process.platform === 'win32') {
+    app.setAppUserModelId(WINDOWS_APP_USER_MODEL_ID);
   }
-});
 
-// Application lifecycle
-app.whenReady().then(() => {
-  void initialize().catch((error) => {
-    logger.error('Application initialization failed:', error);
+  gatewayManager = new GatewayManager();
+  clawHubService = new ClawHubService();
+  hostEventBus = new HostEventBus();
+
+  // When a second instance is launched, focus the existing window instead.
+  app.on('second-instance', () => {
+    logger.info('Second ClawX instance detected; redirecting to the existing window');
+
+    const focusRequest = requestSecondInstanceFocus(
+      mainWindowFocusState,
+      Boolean(mainWindow && !mainWindow.isDestroyed()),
+    );
+
+    if (focusRequest === 'focus-now') {
+      focusMainWindow();
+      return;
+    }
+
+    logger.debug('Main window is not ready yet; deferring second-instance focus until ready-to-show');
   });
 
-  // Register activate handler AFTER app is ready to prevent
-  // "Cannot create BrowserWindow before app is ready" on macOS.
-  app.on('activate', () => {
-    if (BrowserWindow.getAllWindows().length === 0) {
-      mainWindow = createWindow();
-    } else if (mainWindow && !mainWindow.isDestroyed()) {
-      // On macOS, clicking the dock icon should show the window if it's hidden
-      mainWindow.show();
-      mainWindow.focus();
+  // Application lifecycle
+  app.whenReady().then(() => {
+    void initialize().catch((error) => {
+      logger.error('Application initialization failed:', error);
+    });
+
+    // Register activate handler AFTER app is ready to prevent
+    // "Cannot create BrowserWindow before app is ready" on macOS.
+    app.on('activate', () => {
+      if (BrowserWindow.getAllWindows().length === 0) {
+        createMainWindow();
+      } else {
+        focusMainWindow();
+      }
+    });
+  });
+
+  app.on('window-all-closed', () => {
+    if (process.platform !== 'darwin') {
+      app.quit();
     }
   });
-});
 
-app.on('window-all-closed', () => {
-  if (process.platform !== 'darwin') {
-    app.quit();
-  }
-});
-
-app.on('before-quit', () => {
-  setQuitting();
-  hostEventBus.closeAll();
-  hostApiServer?.close();
-  // Fire-and-forget: do not await gatewayManager.stop() here.
-  // Awaiting inside before-quit can stall Electron's quit sequence.
-  void gatewayManager.stop().catch((err) => {
-    logger.warn('gatewayManager.stop() error during quit:', err);
+  app.on('before-quit', () => {
+    setQuitting();
+    hostEventBus.closeAll();
+    hostApiServer?.close();
+    // Fire-and-forget: do not await gatewayManager.stop() here.
+    // Awaiting inside before-quit can stall Electron's quit sequence.
+    void gatewayManager.stop().catch((err) => {
+      logger.warn('gatewayManager.stop() error during quit:', err);
+    });
   });
-});
+}
 
 // Export for testing
 export { mainWindow, gatewayManager };

electron/main/main-window-focus.ts

@@ -0,0 +1,38 @@
+export interface MainWindowFocusState {
+  pendingSecondInstanceFocus: boolean;
+}
+
+export type SecondInstanceFocusRequest = 'focus-now' | 'defer';
+export type MainWindowReadyAction = 'show' | 'focus';
+
+export function createMainWindowFocusState(): MainWindowFocusState {
+  return {
+    pendingSecondInstanceFocus: false,
+  };
+}
+
+export function requestSecondInstanceFocus(
+  state: MainWindowFocusState,
+  hasFocusableMainWindow: boolean,
+): SecondInstanceFocusRequest {
+  if (hasFocusableMainWindow) {
+    state.pendingSecondInstanceFocus = false;
+    return 'focus-now';
+  }
+
+  state.pendingSecondInstanceFocus = true;
+  return 'defer';
+}
+
+export function consumeMainWindowReady(state: MainWindowFocusState): MainWindowReadyAction {
+  if (state.pendingSecondInstanceFocus) {
+    state.pendingSecondInstanceFocus = false;
+    return 'focus';
+  }
+
+  return 'show';
+}
+
+export function clearPendingSecondInstanceFocus(state: MainWindowFocusState): void {
+  state.pendingSecondInstanceFocus = false;
+}

tests/unit/main-window-focus.test.ts

@@ -0,0 +1,32 @@
+import { describe, expect, it } from 'vitest';
+import {
+  consumeMainWindowReady,
+  createMainWindowFocusState,
+  requestSecondInstanceFocus,
+} from '@electron/main/main-window-focus';
+
+describe('main window focus coordination', () => {
+  it('defers second-instance focus until the main window is ready', () => {
+    const state = createMainWindowFocusState();
+
+    expect(requestSecondInstanceFocus(state, false)).toBe('defer');
+    expect(state.pendingSecondInstanceFocus).toBe(true);
+    expect(consumeMainWindowReady(state)).toBe('focus');
+    expect(state.pendingSecondInstanceFocus).toBe(false);
+  });
+
+  it('shows the main window normally when no second-instance focus is pending', () => {
+    const state = createMainWindowFocusState();
+
+    expect(consumeMainWindowReady(state)).toBe('show');
+    expect(state.pendingSecondInstanceFocus).toBe(false);
+  });
+
+  it('focuses immediately when the main window already exists', () => {
+    const state = createMainWindowFocusState();
+    requestSecondInstanceFocus(state, false);
+
+    expect(requestSecondInstanceFocus(state, true)).toBe('focus-now');
+    expect(state.pendingSecondInstanceFocus).toBe(false);
+  });
+});