auth-compat module incorrectly detects Capacitor/Cordova environment on iPad

[dpa99c]

Operating System

iPadOS 17.6.1

Environment (if applicable)

Cordova/Capacitor app running in WKWebview on iPadOS

Firebase SDK Version

11.2.0

Firebase SDK Product(s)

Auth

Project Tooling

Cordova app with webpack

Detailed Problem Description

The auth-compat module relies on matching the URL scheme and user agent string to detect whether it is running in a Cordova/Capacitor Webview in _isAndroidOrIosCordovaScheme.

However, since iPadOS 13 (circa 2019), Safari (and its WKWebView implementation) began identifying itself with a user agent string similar to that of macOS to provide a desktop-like browsing experience. This change means that the user agent string no longer contains iPad and instead resembles that of a Mac.
For example the user agent string of my iPad Simulator is Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148.

This means the current detection fails to correctly detect that it is running in a Cordova/Capacitor Webview when running on an iPad, so assumes it's a desktop browser environment.
Therefore when the auth-compat module is imported, this leads to a run-time error:

Steps and code to reproduce issue

• On macOS with ionic environment for iOS development for Cordova:
• Run in Terminal:
  • ionic start firebase-test blank --type=angular --cordova && cd firebase-test
  • npm install -g @angular/cli
  • ng add @ionic/cordova-builders
  • ionic cordova platform add ios
• Edit src/main.ts and add:

window.onerror = function (message) {
  alert(message);
}

• Run in Terminal:
  • ionic build
  • cordova platform prepare ios
• Open platforms/ios/firebase-test.xcworkspace in Xcode
• In Xcode, select a connected physical iPad or an iPad Simulator and then select "Run"
• Observe that app launches without errors

Then add the Firebase SDK:

• Run in Terminal: npm i firebase
• Edit src/main.ts and add:

import firebase from '@firebase/app-compat';
import '@firebase/auth-compat';

const config = {
  // your project config
};
firebase.initializeApp(config)
console.log(firebase.auth().currentUser);

• Run in Terminal:
  • ionic build
  • ionic cordova prepare ios
• In Xcode, select a connected physical iPad or an iPad Simulator and then select "Run"
• Observe than an error dialog appears
• Inspect Webview with Safari Devtools and observer errors are due to Firebase SDK

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[jbalidiong]

Hi @dpa99c, thank you for bringing this to our attention. I was able to replicate the issue. I'll take a closer look and see what we can do or loop in someone who has more context. I'll update this thread as soon as I have more details or information to share.