This repository serves as a minimal reproduction of a bug in expo-web-browser and includes the pre-packaged fix for verification.

Related PR: expo/expo#41179

The Issue: On the web, when WebBrowser.openBrowserAsync() is blocked by the browser (e.g., inside in-app browsers like Instagram/Facebook or when triggered without a user gesture), it incorrectly resolves with { type: "opened" } instead of throwing an error.

The Fix: This repository includes a local build (.tgz) of the modified expo-web-browser package that correctly checks for blocked popups and throws ERR_WEB_BROWSER_BLOCKED.

• App Code: A minimal Expo app that triggers openBrowserAsync on mount (simulating a blocked popup).
• Patched Package: expo-web-browser-xx.x.x.tgz (Located in the root). This contains the fix applied in the PR.

1. Clone the repository:

   git clone https://github.com/YOUR_USERNAME/expo-web-browser-blocked-popup-repro.git
   cd expo-web-browser-blocked-popup-repro/test-app

2. Install dependencies: This will automatically install the included patched version of expo-web-browser from the local .tgz file.

   npm install

3. Run on web:

   npx expo start --web

4. Verify the Fix:

   • The included .tgz (expo-web-browser-15.0.7.tgz) will not be automatically installed by npm install when running in the test-app folder.

   Install it manually using one of the commands below from the test-app directory:

   • npm install ./expo-web-browser-15.0.7.tgz

   • npm install /full/path/to/expo-web-browser-15.0.7.tgz

   • Or run npm install then drag-and-drop the expo-web-browser-15.0.7.tgz file into your terminal to paste the path, then press Enter.

   • To reproduce a blocked popup you can either enable your browser's popup blocking or run the app in Incognito/Private mode (which often blocks automatic popups).

   Steps to Block Popups in Common Browsers

   Browser	Steps to Block Popups
   Chrome	Settings → Privacy and security → Site Settings → Pop-ups and redirects → set to Blocked
   Safari (macOS)	Safari → Settings → Websites → Pop-up Windows → choose Block for the site or When visiting other websites: Block
   Firefox	Preferences → Privacy & Security → Permissions → check Block pop-up windows

   Note: You can also test inside in-app browsers (Instagram/Facebook), where popups are often blocked by design.
   The test app triggers WebBrowser.openBrowserAsync() automatically on mount to simulate the condition.

   • Expected Result: The popup is blocked and the app displays "BLOCKED! Error caught: ERR_WEB_BROWSER_BLOCKED" (or shows an error alert), indicating the patched expo-web-browser correctly detects blocked popups.|

     After.mov

   • Without the fix, the app will often display "FAILED TO BLOCK" because the library incorrectly returns a success result even when the browser blocked the popup.

     Before.mov