From 596f497633c2d7719c7ad65b9ad6e050db8ad387 Mon Sep 17 00:00:00 2001
From: Max Schmitt <max@schmitt.mx>
Date: Mon, 26 Aug 2024 17:27:21 +0200
Subject: [PATCH] fix: don't throw error on about:blank when blocking
 ServiceWorker (#32310)

Fixes https://github.com/microsoft/playwright/issues/32292
---
 packages/playwright-core/src/server/browserContext.ts     | 2 +-
 .../library/browsercontext-service-worker-policy.spec.ts  | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/packages/playwright-core/src/server/browserContext.ts b/packages/playwright-core/src/server/browserContext.ts
index db20728904..09b84b267f 100644
--- a/packages/playwright-core/src/server/browserContext.ts
+++ b/packages/playwright-core/src/server/browserContext.ts
@@ -142,7 +142,7 @@ export abstract class BrowserContext extends SdkObject {
     if (debugMode() === 'console')
       await this.extendInjectedScript(consoleApiSource.source);
     if (this._options.serviceWorkers === 'block')
-      await this.addInitScript(`\nnavigator.serviceWorker.register = async () => { console.warn('Service Worker registration blocked by Playwright'); };\n`);
+      await this.addInitScript(`\nif (navigator.serviceWorker) navigator.serviceWorker.register = async () => { console.warn('Service Worker registration blocked by Playwright'); };\n`);
 
     if (this._options.permissions)
       await this.grantPermissions(this._options.permissions);
diff --git a/tests/library/browsercontext-service-worker-policy.spec.ts b/tests/library/browsercontext-service-worker-policy.spec.ts
index 213cf1461a..1923a2dc4e 100644
--- a/tests/library/browsercontext-service-worker-policy.spec.ts
+++ b/tests/library/browsercontext-service-worker-policy.spec.ts
@@ -29,4 +29,12 @@ it.describe('block', () => {
       page.goto(server.PREFIX + '/serviceworkers/empty/sw.html'),
     ]);
   });
+
+  it('should not throw error on about:blank', async ({ page }) => {
+    it.info().annotations.push({ type: 'issue', description: 'https://github.com/microsoft/playwright/issues/32292' });
+    const errors = [];
+    page.on('pageerror', error => errors.push(error));
+    await page.goto('about:blank');
+    expect(errors).toEqual([]);
+  });
 });