[Bug]: Apple Background Push Notification terminates app

[cburns-pw]

[Bug]: Apple Background Push Notification terminates app

[aritchie]

Include a reproducible sample or it didn't happen

[cburns-pw]

How do you suggest I include a reproducible sample that includes Apple certificates to send push notifications?
If I change this delegate:

[Export("application:didReceiveRemoteNotification:fetchCompletionHandler:")]
    public void DidReceiveRemoteNotification(UIApplication application, NSDictionary userInfo, Action<UIBackgroundFetchResult> completionHandler) 
        => Host.Lifecycle.OnDidReceiveRemoteNotification(userInfo, completionHandler);

to

[Export("application:didReceiveRemoteNotification:fetchCompletionHandler:")]
public void DidReceiveRemoteNotification(UIApplication application, NSDictionary userInfo, Action<UIBackgroundFetchResult> completionHandler) 
{
    Debug.WriteLine(userInfo);
}

The app prints userInfo and the app does not crash.

[aritchie]

You don't have to include the certs. I don't need them. If you don't file a repro, I will close this though. Please be respectful of the issue template.

[cburns-pw]

You don't have to include the certs. I don't need them. If you don't file a repro, I will close this though. Please be respectful of the issue template.

I updated with a repo.

[cburns-pw]

I decided to pull the shiny repo and add it to my project to try to figure out what was wrong.
I believe I found what is causing it.
You can't Invoke the completion handler more than once or at least this part of the code is what is causing the app the terminate:

    public void OnDidReceive(NSDictionary userInfo, Action<UIBackgroundFetchResult> completionHandler)
    {
        this.logger.LogDebug("Incoming Background remote notification");

        var dict = userInfo.FromNsDictionary();
        var data = new PushNotification(dict, null);
        this.services
            .RunDelegates<IPushDelegate>(
                x => x.OnReceived(data),
                this.logger
            )
            .ContinueWith(_ => completionHandler.Invoke(UIBackgroundFetchResult.NewData));

        completionHandler.Invoke(UIBackgroundFetchResult.NewData);
    }

Removing completionHandler.Invoke(UIBackgroundFetchResult.NewData); results in a successful background fetch.