chore: use a single binding for all Playwright needs (#32039)

This makes it easier to manage bindings, being just init scripts.
Fixes the BFCache binding problem.
Makes bindings removable in Firefox.

Fixes #31515.

packages/playwright-core/src/server/browserContext.ts

@@ -86,7 +86,7 @@ export abstract class BrowserContext extends SdkObject {
   private _customCloseHandler?: () => Promise<any>;
   readonly _tempDirs: string[] = [];
   private _settingStorageState = false;
-  readonly initScripts: InitScript[] = [];
+  initScripts: InitScript[] = [];
   private _routesInFlight = new Set<network.Route>();
   private _debugger!: Debugger;
   _closeReason: string | undefined;
@@ -271,9 +271,7 @@ export abstract class BrowserContext extends SdkObject {
   protected abstract doClearPermissions(): Promise<void>;
   protected abstract doSetHTTPCredentials(httpCredentials?: types.Credentials): Promise<void>;
   protected abstract doAddInitScript(initScript: InitScript): Promise<void>;
-  protected abstract doRemoveInitScripts(): Promise<void>;
+  protected abstract doRemoveNonInternalInitScripts(): Promise<void>;
-  protected abstract doExposeBinding(binding: PageBinding): Promise<void>;
-  protected abstract doRemoveExposedBindings(): Promise<void>;
   protected abstract doUpdateRequestInterception(): Promise<void>;
   protected abstract doClose(reason: string | undefined): Promise<void>;
   protected abstract onClosePersistent(): void;
@@ -320,15 +318,16 @@ export abstract class BrowserContext extends SdkObject {
     }
     const binding = new PageBinding(name, playwrightBinding, needsHandle);
     this._pageBindings.set(name, binding);
-    await this.doExposeBinding(binding);
+    await this.doAddInitScript(binding.initScript);
+    const frames = this.pages().map(page => page.frames()).flat();
+    await Promise.all(frames.map(frame => frame.evaluateExpression(binding.initScript.source).catch(e => {})));
   }
 
   async _removeExposedBindings() {
-    for (const key of this._pageBindings.keys()) {
+    for (const [key, binding] of this._pageBindings) {
-      if (!key.startsWith('__pw'))
+      if (!binding.internal)
         this._pageBindings.delete(key);
     }
-    await this.doRemoveExposedBindings();
   }
 
   async grantPermissions(permissions: string[], origin?: string) {
@@ -414,8 +413,8 @@ export abstract class BrowserContext extends SdkObject {
   }
 
   async _removeInitScripts(): Promise<void> {
-    this.initScripts.splice(0, this.initScripts.length);
+    this.initScripts = this.initScripts.filter(script => script.internal);
-    await this.doRemoveInitScripts();
+    await this.doRemoveNonInternalInitScripts();
   }
 
   async setRequestInterceptor(handler: network.RouteHandler | undefined): Promise<void> {

packages/playwright-core/src/server/chromium/crBrowser.ts

@@ -21,7 +21,7 @@ import { Browser } from '../browser';
 import { assertBrowserContextIsNotOwned, BrowserContext, verifyGeolocation } from '../browserContext';
 import { assert, createGuid } from '../../utils';
 import * as network from '../network';
-import type { InitScript, PageBinding, PageDelegate, Worker } from '../page';
+import type { InitScript, PageDelegate, Worker } from '../page';
 import { Page } from '../page';
 import { Frame } from '../frames';
 import type { Dialog } from '../dialog';
@@ -491,19 +491,9 @@ export class CRBrowserContext extends BrowserContext {
       await (page._delegate as CRPage).addInitScript(initScript);
   }
 
-  async doRemoveInitScripts() {
+  async doRemoveNonInternalInitScripts() {
     for (const page of this.pages())
-      await (page._delegate as CRPage).removeInitScripts();
+      await (page._delegate as CRPage).removeNonInternalInitScripts();
-  }
-
-  async doExposeBinding(binding: PageBinding) {
-    for (const page of this.pages())
-      await (page._delegate as CRPage).exposeBinding(binding);
-  }
-
-  async doRemoveExposedBindings() {
-    for (const page of this.pages())
-      await (page._delegate as CRPage).removeExposedBindings();
   }
 
   async doUpdateRequestInterception(): Promise<void> {

packages/playwright-core/src/server/chromium/crPage.ts

@@ -26,7 +26,7 @@ import * as dom from '../dom';
 import * as frames from '../frames';
 import { helper } from '../helper';
 import * as network from '../network';
-import type { InitScript, PageBinding, PageDelegate } from '../page';
+import { type InitScript, PageBinding, type PageDelegate } from '../page';
 import { Page, Worker } from '../page';
 import type { Progress } from '../progress';
 import type * as types from '../types';
@@ -182,15 +182,6 @@ export class CRPage implements PageDelegate {
     return this._sessionForFrame(frame)._navigate(frame, url, referrer);
   }
 
-  async exposeBinding(binding: PageBinding) {
-    await this._forAllFrameSessions(frame => frame._initBinding(binding));
-    await Promise.all(this._page.frames().map(frame => frame.evaluateExpression(binding.source).catch(e => {})));
-  }
-
-  async removeExposedBindings() {
-    await this._forAllFrameSessions(frame => frame._removeExposedBindings());
-  }
-
   async updateExtraHTTPHeaders(): Promise<void> {
     const headers = network.mergeHeaders([
       this._browserContext._options.extraHTTPHeaders,
@@ -260,7 +251,7 @@ export class CRPage implements PageDelegate {
     await this._forAllFrameSessions(frame => frame._evaluateOnNewDocument(initScript, world));
   }
 
-  async removeInitScripts() {
+  async removeNonInternalInitScripts() {
     await this._forAllFrameSessions(frame => frame._removeEvaluatesOnNewDocument());
   }
 
@@ -420,7 +411,6 @@ class FrameSession {
   private _screencastId: string | null = null;
   private _screencastClients = new Set<any>();
   private _evaluateOnNewDocumentIdentifiers: string[] = [];
-  private _exposedBindingNames: string[] = [];
   private _metricsOverride: Protocol.Emulation.setDeviceMetricsOverrideParameters | undefined;
   private _workerSessions = new Map<string, CRSession>();
 
@@ -519,9 +509,7 @@ class FrameSession {
             grantUniveralAccess: true,
             worldName: UTILITY_WORLD_NAME,
           });
-          for (const binding of this._crPage._browserContext._pageBindings.values())
+          for (const initScript of this._crPage._page.allInitScripts())
-            frame.evaluateExpression(binding.source).catch(e => {});
-          for (const initScript of this._crPage._browserContext.initScripts)
             frame.evaluateExpression(initScript.source).catch(e => {});
         }
 
@@ -541,6 +529,7 @@ class FrameSession {
       this._client.send('Log.enable', {}),
       lifecycleEventsEnabled = this._client.send('Page.setLifecycleEventsEnabled', { enabled: true }),
       this._client.send('Runtime.enable', {}),
+      this._client.send('Runtime.addBinding', { name: PageBinding.kPlaywrightBinding }),
       this._client.send('Page.addScriptToEvaluateOnNewDocument', {
         source: '',
         worldName: UTILITY_WORLD_NAME,
@@ -573,11 +562,7 @@ class FrameSession {
       promises.push(this._updateGeolocation(true));
       promises.push(this._updateEmulateMedia());
       promises.push(this._updateFileChooserInterception(true));
-      for (const binding of this._crPage._page.allBindings())
+      for (const initScript of this._crPage._page.allInitScripts())
-        promises.push(this._initBinding(binding));
-      for (const initScript of this._crPage._browserContext.initScripts)
-        promises.push(this._evaluateOnNewDocument(initScript, 'main'));
-      for (const initScript of this._crPage._page.initScripts)
         promises.push(this._evaluateOnNewDocument(initScript, 'main'));
       if (screencastOptions)
         promises.push(this._startVideoRecording(screencastOptions));
@@ -834,25 +819,6 @@ class FrameSession {
     this._page._addConsoleMessage(event.type, values, toConsoleMessageLocation(event.stackTrace));
   }
 
-  async _initBinding(binding: PageBinding) {
-    const [, response] = await Promise.all([
-      this._client.send('Runtime.addBinding', { name: binding.name }),
-      this._client.send('Page.addScriptToEvaluateOnNewDocument', { source: binding.source })
-    ]);
-    this._exposedBindingNames.push(binding.name);
-    if (!binding.name.startsWith('__pw'))
-      this._evaluateOnNewDocumentIdentifiers.push(response.identifier);
-  }
-
-  async _removeExposedBindings() {
-    const toRetain: string[] = [];
-    const toRemove: string[] = [];
-    for (const name of this._exposedBindingNames)
-      (name.startsWith('__pw_') ? toRetain : toRemove).push(name);
-    this._exposedBindingNames = toRetain;
-    await Promise.all(toRemove.map(name => this._client.send('Runtime.removeBinding', { name })));
-  }
-
   async _onBindingCalled(event: Protocol.Runtime.bindingCalledPayload) {
     const pageOrError = await this._crPage.pageOrError();
     if (!(pageOrError instanceof Error)) {
@@ -1102,6 +1068,7 @@ class FrameSession {
   async _evaluateOnNewDocument(initScript: InitScript, world: types.World): Promise<void> {
     const worldName = world === 'utility' ? UTILITY_WORLD_NAME : undefined;
     const { identifier } = await this._client.send('Page.addScriptToEvaluateOnNewDocument', { source: initScript.source, worldName });
+    if (!initScript.internal)
       this._evaluateOnNewDocumentIdentifiers.push(identifier);
   }
 

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

@@ -21,7 +21,8 @@ import type { BrowserOptions } from '../browser';
 import { Browser } from '../browser';
 import { assertBrowserContextIsNotOwned, BrowserContext, verifyGeolocation } from '../browserContext';
 import * as network from '../network';
-import type { InitScript, Page, PageBinding, PageDelegate } from '../page';
+import type { InitScript, Page, PageDelegate } from '../page';
+import { PageBinding } from '../page';
 import type { ConnectionTransport } from '../transport';
 import type * as types from '../types';
 import type * as channels from '@protocol/channels';
@@ -178,7 +179,10 @@ export class FFBrowserContext extends BrowserContext {
   override async _initialize() {
     assert(!this._ffPages().length);
     const browserContextId = this._browserContextId;
-    const promises: Promise<any>[] = [super._initialize()];
+    const promises: Promise<any>[] = [
+      super._initialize(),
+      this._browser.session.send('Browser.addBinding', { browserContextId: this._browserContextId, name: PageBinding.kPlaywrightBinding, script: '' }),
+    ];
     if (this._options.acceptDownloads !== 'internal-browser-default') {
       promises.push(this._browser.session.send('Browser.setDownloadOptions', {
         browserContextId,
@@ -353,21 +357,17 @@ export class FFBrowserContext extends BrowserContext {
   }
 
   async doAddInitScript(initScript: InitScript) {
-    await this._browser.session.send('Browser.setInitScripts', { browserContextId: this._browserContextId, scripts: this.initScripts.map(script => ({ script: script.source })) });
+    await this._updateInitScripts();
   }
 
-  async doRemoveInitScripts() {
+  async doRemoveNonInternalInitScripts() {
-    await this._browser.session.send('Browser.setInitScripts', { browserContextId: this._browserContextId, scripts: [] });
+    await this._updateInitScripts();
   }
 
-  async doExposeBinding(binding: PageBinding) {
+  private async _updateInitScripts() {
-    await this._browser.session.send('Browser.addBinding', { browserContextId: this._browserContextId, name: binding.name, script: binding.source });
+    const bindingScripts = [...this._pageBindings.values()].map(binding => binding.initScript.source);
-  }
+    const initScripts = this.initScripts.map(script => script.source);
-
+    await this._browser.session.send('Browser.setInitScripts', { browserContextId: this._browserContextId, scripts: [...bindingScripts, ...initScripts].map(script => ({ script })) });
-  async doRemoveExposedBindings() {
-    // TODO: implement me.
-    // This is not a critical problem, what ends up happening is
-    // an old binding will be restored upon page reload and will point nowhere.
   }
 
   async doUpdateRequestInterception(): Promise<void> {

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

@@ -20,7 +20,7 @@ import * as dom from '../dom';
 import type * as frames from '../frames';
 import type { RegisteredListener } from '../../utils/eventsHelper';
 import { eventsHelper } from '../../utils/eventsHelper';
-import type { PageBinding, PageDelegate } from '../page';
+import type { PageDelegate } from '../page';
 import { InitScript } from '../page';
 import { Page, Worker } from '../page';
 import type * as types from '../types';
@@ -114,7 +114,7 @@ export class FFPage implements PageDelegate {
     });
     // Ideally, we somehow ensure that utility world is created before Page.ready arrives, but currently it is racy.
     // Therefore, we can end up with an initialized page without utility world, although very unlikely.
-    this.addInitScript(new InitScript(''), UTILITY_WORLD_NAME).catch(e => this._markAsError(e));
+    this.addInitScript(new InitScript('', true), UTILITY_WORLD_NAME).catch(e => this._markAsError(e));
   }
 
   potentiallyUninitializedPage(): Page {
@@ -336,14 +336,6 @@ export class FFPage implements PageDelegate {
     this._browserContext._browser._videoStarted(this._browserContext, event.screencastId, event.file, this.pageOrError());
   }
 
-  async exposeBinding(binding: PageBinding) {
-    await this._session.send('Page.addBinding', { name: binding.name, script: binding.source });
-  }
-
-  async removeExposedBindings() {
-    // TODO: implement me.
-  }
-
   didClose() {
     this._markAsError(new TargetClosedError());
     this._session.dispose();
@@ -412,9 +404,9 @@ export class FFPage implements PageDelegate {
     await this._session.send('Page.setInitScripts', { scripts: this._initScripts.map(s => ({ script: s.initScript.source, worldName: s.worldName })) });
   }
 
-  async removeInitScripts() {
+  async removeNonInternalInitScripts() {
-    this._initScripts = [];
+    this._initScripts = this._initScripts.filter(s => s.initScript.internal);
-    await this._session.send('Page.setInitScripts', { scripts: [] });
+    await this._session.send('Page.setInitScripts', { scripts: this._initScripts.map(s => ({ script: s.initScript.source, worldName: s.worldName })) });
   }
 
   async closePage(runBeforeUnload: boolean): Promise<void> {

packages/playwright-core/src/server/page.ts

@@ -54,10 +54,8 @@ export interface PageDelegate {
   reload(): Promise<void>;
   goBack(): Promise<boolean>;
   goForward(): Promise<boolean>;
-  exposeBinding(binding: PageBinding): Promise<void>;
-  removeExposedBindings(): Promise<void>;
   addInitScript(initScript: InitScript): Promise<void>;
-  removeInitScripts(): Promise<void>;
+  removeNonInternalInitScripts(): Promise<void>;
   closePage(runBeforeUnload: boolean): Promise<void>;
   potentiallyUninitializedPage(): Page;
   pageOrError(): Promise<Page | Error>;
@@ -154,7 +152,7 @@ export class Page extends SdkObject {
   private _emulatedMedia: Partial<EmulatedMedia> = {};
   private _interceptFileChooser = false;
   private readonly _pageBindings = new Map<string, PageBinding>();
-  readonly initScripts: InitScript[] = [];
+  initScripts: InitScript[] = [];
   readonly _screenshotter: Screenshotter;
   readonly _frameManager: frames.FrameManager;
   readonly accessibility: accessibility.Accessibility;
@@ -342,15 +340,15 @@ export class Page extends SdkObject {
       throw new Error(`Function "${name}" has been already registered in the browser context`);
     const binding = new PageBinding(name, playwrightBinding, needsHandle);
     this._pageBindings.set(name, binding);
-    await this._delegate.exposeBinding(binding);
+    await this._delegate.addInitScript(binding.initScript);
+    await Promise.all(this.frames().map(frame => frame.evaluateExpression(binding.initScript.source).catch(e => {})));
   }
 
   async _removeExposedBindings() {
-    for (const key of this._pageBindings.keys()) {
+    for (const [key, binding] of this._pageBindings) {
-      if (!key.startsWith('__pw'))
+      if (!binding.internal)
         this._pageBindings.delete(key);
     }
-    await this._delegate.removeExposedBindings();
   }
 
   setExtraHTTPHeaders(headers: types.HeadersArray) {
@@ -533,8 +531,8 @@ export class Page extends SdkObject {
   }
 
   async _removeInitScripts() {
-    this.initScripts.splice(0, this.initScripts.length);
+    this.initScripts = this.initScripts.filter(script => script.internal);
-    await this._delegate.removeInitScripts();
+    await this._delegate.removeNonInternalInitScripts();
   }
 
   needsRequestInterception(): boolean {
@@ -727,8 +725,9 @@ export class Page extends SdkObject {
       this._browserContext.addVisitedOrigin(origin);
   }
 
-  allBindings() {
+  allInitScripts() {
-    return [...this._browserContext._pageBindings.values(), ...this._pageBindings.values()];
+    const bindings = [...this._browserContext._pageBindings.values(), ...this._pageBindings.values()];
+    return [...bindings.map(binding => binding.initScript), ...this._browserContext.initScripts, ...this.initScripts];
   }
 
   getBinding(name: string) {
@@ -819,23 +818,29 @@ type BindingPayload = {
 };
 
 export class PageBinding {
+  static kPlaywrightBinding = '__playwright__binding__';
+
   readonly name: string;
   readonly playwrightFunction: frames.FunctionWithSource;
-  readonly source: string;
+  readonly initScript: InitScript;
   readonly needsHandle: boolean;
+  readonly internal: boolean;
 
   constructor(name: string, playwrightFunction: frames.FunctionWithSource, needsHandle: boolean) {
     this.name = name;
     this.playwrightFunction = playwrightFunction;
-    this.source = `(${addPageBinding.toString()})(${JSON.stringify(name)}, ${needsHandle}, (${source})())`;
+    this.initScript = new InitScript(`(${addPageBinding.toString()})(${JSON.stringify(PageBinding.kPlaywrightBinding)}, ${JSON.stringify(name)}, ${needsHandle}, (${source})())`, true /* internal */);
     this.needsHandle = needsHandle;
+    this.internal = name.startsWith('__pw');
   }
 
   static async dispatch(page: Page, payload: string, context: dom.FrameExecutionContext) {
     const { name, seq, serializedArgs } = JSON.parse(payload) as BindingPayload;
     try {
       assert(context.world);
-      const binding = page.getBinding(name)!;
+      const binding = page.getBinding(name);
+      if (!binding)
+        throw new Error(`Function "${name}" is not exposed`);
       let result: any;
       if (binding.needsHandle) {
         const handle = await context.evaluateHandle(takeHandle, { name, seq }).catch(e => null);
@@ -877,10 +882,8 @@ export class PageBinding {
   }
 }
 
-function addPageBinding(bindingName: string, needsHandle: boolean, utilityScriptSerializers: ReturnType<typeof source>) {
+function addPageBinding(playwrightBinding: string, bindingName: string, needsHandle: boolean, utilityScriptSerializers: ReturnType<typeof source>) {
-  const binding = (globalThis as any)[bindingName];
+  const binding = (globalThis as any)[playwrightBinding];
-  if (binding.__installed)
-    return;
   (globalThis as any)[bindingName] = (...args: any[]) => {
     const me = (globalThis as any)[bindingName];
     if (needsHandle && args.slice(1).some(arg => arg !== undefined))
@@ -919,8 +922,9 @@ function addPageBinding(bindingName: string, needsHandle: boolean, utilityScript
 
 export class InitScript {
   readonly source: string;
+  readonly internal: boolean;
 
-  constructor(source: string) {
+  constructor(source: string, internal?: boolean) {
     const guid = createGuid();
     this.source = `(() => {
       globalThis.__pwInitScripts = globalThis.__pwInitScripts || {};
@@ -930,6 +934,7 @@ export class InitScript {
       globalThis.__pwInitScripts[${JSON.stringify(guid)}] = true;
       ${source}
     })();`;
+    this.internal = !!internal;
   }
 }
 

packages/playwright-core/src/server/webkit/wkBrowser.ts

@@ -22,7 +22,7 @@ import type { RegisteredListener } from '../../utils/eventsHelper';
 import { assert } from '../../utils';
 import { eventsHelper } from '../../utils/eventsHelper';
 import * as network from '../network';
-import type { InitScript, Page, PageBinding, PageDelegate } from '../page';
+import type { InitScript, Page, PageDelegate } from '../page';
 import type { ConnectionTransport } from '../transport';
 import type * as types from '../types';
 import type * as channels from '@protocol/channels';
@@ -320,21 +320,11 @@ export class WKBrowserContext extends BrowserContext {
       await (page._delegate as WKPage)._updateBootstrapScript();
   }
 
-  async doRemoveInitScripts() {
+  async doRemoveNonInternalInitScripts() {
     for (const page of this.pages())
       await (page._delegate as WKPage)._updateBootstrapScript();
   }
 
-  async doExposeBinding(binding: PageBinding) {
-    for (const page of this.pages())
-      await (page._delegate as WKPage).exposeBinding(binding);
-  }
-
-  async doRemoveExposedBindings() {
-    for (const page of this.pages())
-      await (page._delegate as WKPage).removeExposedBindings();
-  }
-
   async doUpdateRequestInterception(): Promise<void> {
     for (const page of this.pages())
       await (page._delegate as WKPage).updateRequestInterception();

packages/playwright-core/src/server/webkit/wkPage.ts

@@ -30,7 +30,7 @@ import { eventsHelper } from '../../utils/eventsHelper';
 import { helper } from '../helper';
 import type { JSHandle } from '../javascript';
 import * as network from '../network';
-import type { InitScript, PageBinding, PageDelegate } from '../page';
+import { type InitScript, PageBinding, type PageDelegate } from '../page';
 import { Page } from '../page';
 import type { Progress } from '../progress';
 import type * as types from '../types';
@@ -179,6 +179,7 @@ export class WKPage implements PageDelegate {
     const promises: Promise<any>[] = [
       // Resource tree should be received before first execution context.
       session.send('Runtime.enable'),
+      session.send('Runtime.addBinding', { name: PageBinding.kPlaywrightBinding }),
       session.send('Page.createUserWorld', { name: UTILITY_WORLD_NAME }).catch(_ => {}),  // Worlds are per-process
       session.send('Console.enable'),
       session.send('Network.enable'),
@@ -200,8 +201,6 @@ export class WKPage implements PageDelegate {
     const emulatedMedia = this._page.emulatedMedia();
     if (emulatedMedia.media || emulatedMedia.colorScheme || emulatedMedia.reducedMotion || emulatedMedia.forcedColors)
       promises.push(WKPage._setEmulateMedia(session, emulatedMedia.media, emulatedMedia.colorScheme, emulatedMedia.reducedMotion, emulatedMedia.forcedColors));
-    for (const binding of this._page.allBindings())
-      promises.push(session.send('Runtime.addBinding', { name: binding.name }));
     const bootstrapScript = this._calculateBootstrapScript();
     if (bootstrapScript.length)
       promises.push(session.send('Page.setBootstrapScript', { source: bootstrapScript }));
@@ -768,21 +767,11 @@ export class WKPage implements PageDelegate {
     });
   }
 
-  async exposeBinding(binding: PageBinding): Promise<void> {
-    this._session.send('Runtime.addBinding', { name: binding.name });
-    await this._updateBootstrapScript();
-    await Promise.all(this._page.frames().map(frame => frame.evaluateExpression(binding.source).catch(e => {})));
-  }
-
-  async removeExposedBindings(): Promise<void> {
-    await this._updateBootstrapScript();
-  }
-
   async addInitScript(initScript: InitScript): Promise<void> {
     await this._updateBootstrapScript();
   }
 
-  async removeInitScripts() {
+  async removeNonInternalInitScripts() {
     await this._updateBootstrapScript();
   }
 
@@ -795,11 +784,7 @@ export class WKPage implements PageDelegate {
     }
     scripts.push('if (!window.safari) window.safari = { pushNotification: { toString() { return "[object SafariRemoteNotification]"; } } };');
     scripts.push('if (!window.GestureEvent) window.GestureEvent = function GestureEvent() {};');
-
+    scripts.push(...this._page.allInitScripts().map(script => script.source));
-    for (const binding of this._page.allBindings())
-      scripts.push(binding.source);
-    scripts.push(...this._browserContext.initScripts.map(s => s.source));
-    scripts.push(...this._page.initScripts.map(s => s.source));
     return scripts.join(';\n');
   }
 

tests/assets/cached/bfcached.html

@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<link rel='stylesheet' href='./one-style.css'>
+<div>BFCached</div>
+<script>
+  window.didShow = new Promise(f => window.addEventListener('pageshow', event => {
+    console.log(event);
+    window._persisted = !!event.persisted;
+    window._event = event;
+    f({ persisted: !!event.persisted });
+  }));
+</script>

tests/library/chromium/bfcache.spec.ts

@@ -0,0 +1,37 @@
+/**
+ * Copyright Microsoft Corporation. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { contextTest as test, expect } from '../../config/browserTest';
+
+test.use({
+  launchOptions: async ({ launchOptions }, use) => {
+    await use({ ...launchOptions, ignoreDefaultArgs: ['--disable-back-forward-cache'] });
+  }
+});
+
+test('bindings should work after restoring from bfcache', async ({ page, server }) => {
+  await page.exposeFunction('add', (a, b) => a + b);
+
+  await page.goto(server.PREFIX + '/cached/bfcached.html');
+  expect(await page.evaluate('window.add(1, 2)')).toBe(3);
+
+  await page.setContent(`<a href='about:blank'}>click me</a>`);
+  await page.click('a');
+
+  await page.goBack({ waitUntil: 'commit' });
+  await page.evaluate('window.didShow');
+  expect(await page.evaluate('window.add(2, 3)')).toBe(5);
+});

tests/page/page-history.spec.ts

@@ -92,15 +92,17 @@ it('page.goBack should work for file urls', async ({ page, server, asset, browse
 });
 
 it('goBack/goForward should work with bfcache-able pages', async ({ page, server }) => {
-  await page.goto(server.PREFIX + '/cached/one-style.html');
+  await page.goto(server.PREFIX + '/cached/bfcached.html');
-  await page.setContent(`<a href=${JSON.stringify(server.PREFIX + '/cached/one-style.html?foo')}>click me</a>`);
+  await page.setContent(`<a href=${JSON.stringify(server.PREFIX + '/cached/bfcached.html?foo')}>click me</a>`);
   await page.click('a');
 
   let response = await page.goBack();
-  expect(response.url()).toBe(server.PREFIX + '/cached/one-style.html');
+  expect(response.url()).toBe(server.PREFIX + '/cached/bfcached.html');
+  // BFCache should be disabled.
+  expect(await page.evaluate('window.didShow')).toEqual({ persisted: false });
 
   response = await page.goForward();
-  expect(response.url()).toBe(server.PREFIX + '/cached/one-style.html?foo');
+  expect(response.url()).toBe(server.PREFIX + '/cached/bfcached.html?foo');
 });
 
 it('page.reload should work', async ({ page, server }) => {