Flutterfire: 🐛 [firebase_messaging 8.0.0-dev.5] App crashes when opening notification with data message in iOS

[joniaiuser]

Bug report

Describe the bug
I am sending a notification with this payload to the app.

payload = {
                        notification: {
                            title: `You have received a new message!`,
                            body: contentMessage,
                            badge: '1',
                            sound: 'default',
                            click_action: 'FLUTTER_NOTIFICATION_CLICK',
                            idFrom: idFrom,
                            idTo: idTo,
                        },
                        data: {
                                asking: 'true'
                                screen: 'active'
                                type: 'qna',
                                convoId: '123456',
                        },
                    }

The notification is received when app is in background.. When I tap on it, the app opens and then crashes with no error logs.
Simply Lost connection to device.

This is my onMessageOpenedApp function

onMessage = FirebaseMessaging.onMessageOpenedApp
        .listen((RemoteMessage message) async {
      var data = message.data ?? ((message as Map).cast<String, dynamic>());
      if (data['type'] == 'inbox') {
        await goToInbox();
      }
      if (data['type'] == 'qna') {
        await goToQna(data);
      }
    });

I have tried removing the '((message as Map).cast());' before, but it didn't fix it.

When I try to print message, I get flutter: Instance of 'RemoteMessage'
This suggests that my message is being received and the function works, just that I suspect data field is null

Steps to reproduce

Steps to reproduce the behavior:

1. Send a notification with data message to iOS device.
2. Tap on notification to open the app when app is killed or backgrounded.

Expected behavior

1. App should open and navigate to the correct route.

---

Additional context

The code in its old form works when using 7.0.3. I suspect iOS is not handling the data message correctly as previously it was not attached to the 'data' field; the data fields were simply appended to the message directly.. Now there seems to be no way to access those fields as RemoteMessage class hides those fields.

---

Flutter doctor

Run flutter doctor and paste the output below:

Click To Expand

[✓] Flutter (Channel stable, 1.22.3, on Mac OS X 10.15.6 19G2021, locale en-SG)

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.0)
[✓] Xcode - develop for iOS and macOS (Xcode 12.1)
[!] Android Studio (version 4.1)
    ✗ Flutter plugin not installed; this adds Flutter specific functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
[✓] VS Code (version 1.50.1)
[✓] Connected device (3 available)

[Salakar]

When I try to print message, I get flutter: Instance of 'RemoteMessage'
This suggests that my message is being received and the function works, just that I suspect data field is null

If you print message.data does that also cause it to crash, or does that show it as null?

[joniaiuser]

I'm trying that now, will update in a bit.. takes some time to reboot the app as have to do flutter run again everytime it crashes.

[Salakar]

No rush, am about to log off for the night, it's late here, will pick up first thing in morning, but any logs you have will be helpful. Thanks

[joniaiuser]

The code is

   onMessage = FirebaseMessaging.onMessageOpenedApp
        .listen((RemoteMessage message) async {
      print('msg opened app');
      print(message);
      print(message.data);
      if (message.data == null) print('data is null');
      print(message.data['type']);
    });

On a single run..
The logs:

flutter: locale.languageCode: en
flutter: locale.languageCode: en
flutter: msg opened app
flutter: Instance of 'RemoteMessage'
flutter: {screen: active, asking: true, convoId: 5fa1c460bde60900135b923f, type: qna}
flutter: qna
flutter: msg opened app
flutter: Instance of 'RemoteMessage'
flutter: {screen: active, asking: true, convoId: 5fa1c460bde60900135b923f, type: qna}
flutter: qna
flutter: msg opened app
flutter: Instance of 'RemoteMessage'
flutter: {screen: active, asking: true, convoId: 5fa1c460bde60900135b923f, type: qna}
flutter: qna
flutter: msg opened app
flutter: Instance of 'RemoteMessage'
flutter: {screen: active, asking: true, convoId: 5fa1c460bde60900135b923f, type: qna}
flutter: qna
flutter: msg opened app
flutter: Instance of 'RemoteMessage'
flutter: {screen: active, asking: true, convoId: 5fa1c460bde60900135b923f, type: qna}
flutter: qna
flutter: msg opened app
Lost connection to device.

App crashed.

[joniaiuser]

Seems like data is read but app still crashes..

[Salakar]

Interesting, looks like the background handler is getting to the end of the function fine, might be something else causing an asynchronous crash. On Xcode you can attach to a process by name to debug and then send a message - when it comes through and if it crashes you should see the cause of the crash on detox. There's also the Console.app on macOS that will show your devices logs

[Salakar]

Specifically, open your ios/Runner.xcworkspace file in Xcode, then run the app as you normally do through flutter run, and attach using:

Name should be Runner by default but if you've changed your app name then it'll be that.

Alternatively you can just press the play/run button in Xcode and run it that way on your device and debugger will be automatically connected.

[joniaiuser]

Instead of crashing, it now gets stuck at the splash screen when I click on the notification after I attach the process using Xcode.. Not sure what this means

[Salakar]

At the bottom right there should be a logs/debug panel which you can copy logs from. That looks like the Firebsse iOS SDK is throwing an error, just need to see what it is

Could you screenshot the left panel as well, it should show the threads and what looks like a stack trace. Top right there should be buttons to show/hide the various panels.

[joniaiuser]

There weren't any errors. But it's stuck here.

[joniaiuser]

I tried it again.. seems like it keeps printing the print messages over and over.. No error and the app is stuck at splash screen. The debugger prints out (lldb) after some time and stops.

[joniaiuser]

getInitialMessage() seems to have the same crashing issue, although I cannot confirm as not able to get logs when opening the app from a terminated state.

[joniaiuser]

@Salakar Any luck with the repro? Let me know if I can assist further.. really hope to upgrade to v8 soon so that the android notifications with v2 embedding can work properly again!

[Salakar]

Could you share your AppDelegate with me? Struggling to reproduce

[joniaiuser]

import UIKit
import Flutter

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    if #available(iOS 10.0, *) {
      UNUserNotificationCenter.current().delegate = self as? UNUserNotificationCenterDelegate
    } 
    GeneratedPluginRegistrant.register(with: self)
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

[Salakar]

Can you remove;

    if #available(iOS 10.0, *) {
      UNUserNotificationCenter.current().delegate = self as? UNUserNotificationCenterDelegate
    } 

It's not required, did you add this for messaging specifically?

[joniaiuser]

Yes I think so..
Although I believe it was added to allow both local notifications and remote firebase notifications to work at the same time if I didn't recall incorrectly.

[Salakar]

Messaging & local notifications should now both be compatible without any manual changes (we added stuff internally to support this).

[joniaiuser]

I see, let me try it. Wondering if this https://github.com/FirebaseExtended/flutterfire/issues/4034 is related.

[Salakar]

I see, let me try it. Wondering if this #4034 is related.

Have commented there as well, I think it is the same issue.

[Salakar]

Found the bit in the old documentation about it;

If you can confirm this solves your problem and everything still appears to be working then I can add an additional step to the migration guide to remove these.

[joniaiuser]

Ok, what happens now is that the problem with firebase messaging seems resolved BUT my local notification stopped being able to execute onSelectNotification function. Hence when I tap on my local notification, it no longer navigates me to the correct page, instead it only opens the app.

[joniaiuser]

Seems like it's required in their documentation:

https://pub.dev/packages/flutter_local_notifications

[Salakar]

Damn, not sure why though as you can just delegate internally - will have a think and see if I can handle that internally. Whats happening is we're setting a delegate but if there's one there already we keep a reference to it and forward any calls on our delegate to the original, but the above also does that and so we're getting an infinite loop until a stack overflow.

[Salakar]

Can you re-add the code to your delegate, and then I'll see if I can send you over a patch to apply locally quickly to confirm it works

[joniaiuser]

Sure thing, I already have a local copy of your repo. you can let me know which branch.

[Salakar]

Think I have a fix, 1 minute, I'll push up to a branch

[Salakar]

@joniaiuser could you try https://github.com/FirebaseExtended/flutterfire/pull/4043 - thanks

[joniaiuser]

Unfortunately, the crash is back when I add

    if #available(iOS 10.0, *) {
      UNUserNotificationCenter.current().delegate = self as? UNUserNotificationCenterDelegate
    } 

Also noticed the same happens for local notifications, will check if it happens when using .dev5

[joniaiuser]

Let me do a thorough flutter clean and pods delete and give it another try.

[Salakar]

I'm also trying to try on my test iPhone device as well and add in that AppDelegate change, but Xcode has decided it hates me today and can't see my device 😫

[joniaiuser]

Yup, confirmed that the issue exists with the fix.

[Salakar]

Got my device working and have reproduced, leave it with me, am debugging. will get back to you shortly.

[Salakar]

Right I have a fix again, but am just on a call right now. Will push in 20mins or so.

[Salakar]

Ok, just pushed to the same branch @joniaiuser - could you try it again? Thanks :)

[joniaiuser]

Great, seems to be fixed!

[joniaiuser]

iOS seems fine now.. will proceed to test Android. Thanks!

[Salakar]

Great, will ship a dev release shortly, just fixing another issue. Please ping me on the discussion if you come across anymore issues :)

[Salakar]

8.0.0-dev.6 is now up.

[joniaiuser]

If all goes well, we will be planning to try this in production middle of next week.