fix(frontend): browser tab notification respects user-renamed titles; add unit test (#10406)

frontend/__tests__/utils/browser-tab.test.ts

@@ -0,0 +1,51 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
+
+import { browserTab } from "#/utils/browser-tab";
+
+// These tests exercise the browser-tab notification flasher behavior.
+// Specifically we verify that when the document title changes externally
+// while a notification is active, the flasher updates its internal
+// baseline so it restores/toggles to the new title instead of an old one.
+
+describe("browserTab notifications", () => {
+  const MESSAGE = "Agent ready";
+  const INITIAL = "Conversation 123 | OpenHands";
+  const RENAMED = "My renamed title | OpenHands";
+
+  beforeEach(() => {
+    vi.useFakeTimers();
+    // reset title for each test
+    document.title = INITIAL;
+  });
+
+  afterEach(() => {
+    browserTab.stopNotification();
+    vi.runOnlyPendingTimers();
+    vi.useRealTimers();
+  });
+
+  it("updates baseline when title changes during an active notification and restores to the new title", () => {
+    // Start flashing
+    browserTab.startNotification(MESSAGE);
+
+    // Tick once: should switch to the message
+    vi.advanceTimersByTime(1000);
+    expect(document.title).toBe(MESSAGE);
+
+    // Simulate an external rename while flashing (e.g., user edits title)
+    document.title = RENAMED;
+
+    // Next tick: flasher observes the external change and updates baseline
+    vi.advanceTimersByTime(1000);
+    // On this tick, we toggle back to the message
+    expect(document.title).toBe(MESSAGE);
+
+    // Next tick should toggle to the updated baseline (renamed title)
+    vi.advanceTimersByTime(1000);
+    expect(document.title).toBe(RENAMED);
+
+    // Stop flashing: title should remain the updated baseline
+    browserTab.stopNotification();
+    expect(document.title).toBe(RENAMED);
+  });
+});

frontend/src/utils/browser-tab.ts

@@ -11,20 +11,23 @@ export const browserTab = {
   startNotification(message: string) {
     if (!isBrowser) return;
 
-    // Store original title if not already stored
-    if (!originalTitle) {
-      originalTitle = document.title;
-    }
+    // Always capture the current title as the baseline to restore to
+    originalTitle = document.title;
 
     // Clear any existing interval
     if (titleInterval) {
       this.stopNotification();
     }
 
-    // Alternate between original title and notification message
+    // Alternate between the latest baseline title and the notification message.
+    // If the title changes externally (e.g., user renames conversation),
+    // update the baseline so we restore to the new value when stopping.
     titleInterval = window.setInterval(() => {
-      document.title =
-        document.title === originalTitle ? message : originalTitle;
+      const current = document.title;
+      if (current !== originalTitle && current !== message) {
+        originalTitle = current;
+      }
+      document.title = current === message ? originalTitle : message;
     }, 1000);
 
     // Set favicon to indicate notification