fix(firefox): treat navigationCommitted events without navigationId as same-document URL updates

packages/playwright-core/src/server/firefox/ffPage.ts

@@ -239,11 +239,18 @@ export class FFPage implements PageDelegate {
   }
 
   _onNavigationCommitted(params: Protocol.Page.navigationCommittedPayload) {
+    if (!params.navigationId) {
+      // Firefox replays the current navigation without a navigationId during a process swap (e.g. when restoring a persistent profile).
+      // Treat these as same-document URL updates so they don't interrupt any in-flight new-document navigation in Frame.gotoImpl.
+      this._page.frameManager.frameCommittedSameDocumentNavigation(params.frameId, params.url);
+      return;
+    }
+
     for (const [workerId, worker] of this._workers) {
       if (worker.frameId === params.frameId)
         this._onWorkerDestroyed({ workerId });
     }
-    this._page.frameManager.frameCommittedNewDocumentNavigation(params.frameId, params.url, params.name || '', params.navigationId || '', false);
+    this._page.frameManager.frameCommittedNewDocumentNavigation(params.frameId, params.url, params.name || '', params.navigationId, false);
   }
 
   _onSameDocumentNavigation(params: Protocol.Page.sameDocumentNavigationPayload) {

tests/library/defaultbrowsercontext-2.spec.ts

@@ -142,6 +142,23 @@ it('should create userDataDir if it does not exist', async ({ createUserDataDir,
   expect(fs.readdirSync(userDataDir).length).toBeGreaterThan(0);
 });
 
+it('should goto about:blank on relaunched persistent context', {
+  annotation: { type: 'issue', description: 'https://github.com/microsoft/playwright/issues/41216' },
+}, async ({ browserType, createUserDataDir }) => {
+  const userDataDir = await createUserDataDir();
+
+  const context1 = await browserType.launchPersistentContext(userDataDir);
+  await context1.pages()[0].goto('about:blank');
+  await context1.close();
+
+  // When relaunching with an existing profile, Firefox session restore can race with the user's goto and cause "interrupted by another navigation".
+  // This issue is timing-sensitive and might not fire on every run, so rely on CI's --repeat-each matrix for coverage.
+  const context2 = await browserType.launchPersistentContext(userDataDir);
+  await context2.pages()[0].goto('about:blank');
+  expect(context2.pages()[0].url()).toBe('about:blank');
+  await context2.close();
+});
+
 it('should have default URL when launching browser', async ({ launchPersistent }) => {
   const { context } = await launchPersistent();
   const urls = context.pages().map(page => page.url());