Provider: ChangeNotifierProvider can't provide for some reason

[Alfie-AD]

Hi, I have a ChangeNotifierProvider<BoxProvider> above the MaterialApp that is consumed immediately so i use it's value to make a request. For whatever reason it keep returning null, Meanwhile it has the correct value after i have set it deep in a diff. route

class MyApp extends StatelessWidget {
  final fireStoreService = MyFirestoreServices();

  @override
  Widget build(BuildContext context) {
    final _currentUser = Provider.of<FirebaseUser>(context);
    return MultiProvider(
      providers: [
/// the annoying provider!
        ChangeNotifierProvider<BoxProvider>(
            builder: (context) => BoxProvider()),
/// a diff. provider that works fine
        StreamProvider<Person>(
          builder: (context) {
            Stream<Person> _person;
            if (_currentUser != null)
              _person = fireStoreService.streamPerson(_currentUser);
            return _person;
          },
        ),
      ],
/// Both Providers consumed here
      child: Consumer2<BoxProvider, Person>(
        builder: (context, _boxPro, _person, _) {
          if(_boxPro == null) return Text('Loading...');
          return MultiProvider(
            providers: [
              StreamProvider<DocumentSnapshot>(
                builder: (context) {
                  Stream<DocumentSnapshot> docSnapshot;
                  if (_person.hasBoxes)
                    docSnapshot = Firestore.instance
                        .collection('Boxes')
                        .document("${_currentUser.uid}")
                        .snapshots();
                  return docSnapshot;
                },
              ),
              StreamProvider<Box>(
                builder: (context) {
                  Stream<Box> _boxStream;
                  if (_boxPro.boxPath != null)
                    _boxStream = Firestore.instance
/// the value (which is a document path) )is inserted here 
                        .document(_boxPro.boxPath) 
                        .snapshots()
                        .map((Box) => Box.Cloud(...));
                  return _boxStream;
                },
              ),
            ],
            child: MaterialApp(
              home: Home(),
            ),
          );
        },
      ),
    );
  }
}


///setting the path to the selected box in a diff. route
return Consumer<BoxProvider>(
      builder: (context, _boxPro, _) => GestureDetector(
        onTap: () {
          _boxPro.setBoxPath = boxes['boxPath'];
         print("boxProPath: ${_boxPro.boxPath}"); /// returns the desired path.
        },
    ),


class BoxProvider with ChangeNotifier {
  String _boxPath;

  String get boxPath => _boxPath;

  set setBoxPath(String value) {
    _boxPath = value;
    notifyListeners();
  }
}

Box is null when it is consumed which seems to imply the ChangeNotifierProvider<BoxProvider> returns a null.
Don't know how to go about it, please help!

[rrousselGit]

Are you sure that it's not the Person that is null?

[Alfie-AD]

Very very sure. Person is the signed in user and i shouldn't be able to enter the app if it was null.

I've tried a couple of things since this post - i get the desired results when i print boxPath to the console from anywhere except inside MultiProvider between the said consumer Consumer2<BoxProvider, Person>(...) and MaterialApp.
ChangeNotifierProvider<BoxProvider> doesn't return null as i initially thought, I'm just unable to read from between the consumer and MaterialApp

Another interesting development, I have a few more similar ChangeNotifierProvider<T>(...) and they are all behaving in the same way - they all don't return any value between the consumer and the MaterialApp, they are not recognized at all. StreamProvider<Person>(... ) is working fine though. Maybe it has to do with how ChangeNotifierProvider<T>(...) works, you are the expert on that.

In the mean time, do you know of any workaround? Thanks

[rrousselGit]

Hello! Sorry for the late reply.

To be honest I still don't really understand the problem. Do you mind making a minimal reproducible example (no firebase and other noise)?

[rrousselGit]

Closing this since I cannot reproduce the issue