从深层链接启动应用程序时未调用 AppDelegate ContinueUserActivity，应归咎于 Firebase SDK

Question

In my AppDelegate class I'm trying to handle deep links that launch my Xamarin iOS app, so that I can navigate the user to the proper place in the app based on the url. I'm overriding all of the ContinueUserActivity and OpenUrl methods, however none of these methods are ever called (either when the app is closed or just suspended.) I'm testing by including the deep link ( https://example.com/path1/path2 ) in a iOS Calendar event, then tapping on the link on my iPhone 6 (running iOS 12.3.1) while the app is running in debug mode. My app does open when the link is tapped, but none of the break points are hit in any of the overridden methods.

public override bool ContinueUserActivity (UIApplication application, NSUserActivity userActivity, UIApplicationRestorationHandler completionHandler) {
            return true;
        }

    public override bool OpenUrl (UIKit.UIApplication app, Foundation.NSUrl url, Foundation.NSDictionary options) {
                return true;
            }

            public new bool OpenUrl (UIKit.UIApplication app, Foundation.NSUrl url, UIKit.UIApplicationOpenUrlOptions options) {
                return true;
            }

            public override bool OpenUrl (UIApplication application, NSUrl url, string sourceApplication, NSObject annotation) {
                return true;
            }

I think that the universal links are set up correctly (associated domains, etc...), otherwise it wouldn't be launching my app. Also, I've confirmed that my FinishedLaunching method returns true, as I read elsewhere that if this returns false then ContinueUserActivity and OpenUrl aren't called. Other overridden methods in AppDelegate like OnActivated and WillContinueUserActivity are called, but not the ones that I need to get at the deep link url.

Is this a Xamarin iOS bug? Or is there something I'm doing incorrectly? I'm using the latest version of Xamarin iOS (12.8.0.2).

EDIT: A little more info... It turns out that the Firebase SDK is to blame for breaking deep links. If I disable it, then clicking on a deep link will successfully call ContinueUserActivity. However, as soon as I call Firebase.Core.App.Configure(), then subsequent deep link clicks will still open the app but no longer call ContinueUserActivity. I'm not sure how to work around this issue, as I need Firebase for Analytics (Google Analytics is going away soon...)

Answer 1

The credit goes to @Andrew McKinley, but for others who run into the same issue the resolution is to add a new key to your Info.plist file:

Key: FirebaseAppDelegateProxyEnabled Type: Boolean Value: No (false)

After that Firebase stops hijacking handling of deep link urls, so AppDelegate.ContinueUserActivity is correctly called when a deep link is clicked.