Get controller fails assertion after Firebase Authentication

[TJMusiitwa]

After migrating to null safety and using the latest firebase and getx packages, my app is broken.

I am using email link authentication and after I pass the email link back into the application it returns an error that the uid is null.

Inside my BusinessController;

BusinessController(String userId, {FirebaseFirestore firestore})
      : assert(userId != null && userId.isNotEmpty),
        _userId = userId,
        _db = firestore?.collection('business') ??
            FirebaseFirestore.instance.collection('business'),
        super();

  final String _userId;
  final CollectionReference _db;

This assertion here returns null and yet before upgrading to Flutter 2 it worked out well no problem.

My signInwithEmailLink function:

  Future<void> signInWithLink(Uri link) async {
    Loader.show(Get.context, progressIndicator: Spinner());
    // remove the existing listener if it exists to workaround routing not
    // working after sign in
    _userWorker?.dispose();
    final String email = _storage.read('email');
    if (email != null && email.isNotEmpty) {
      printInfo(info: 'signing in with link dynamic link');
      final credential = await _firebaseAuth.signInWithEmailLink(
        email: email,
        emailLink: link.toString(),
      );
      await _storage.remove('email');
      final snapshot = await _db.doc(credential.user.uid).get();
      Loader.hide();
      await navigateUserSignup(UserModel.parse(snapshot.data() ?? {}));
    } else {
      Loader.hide();
    }
    // re-enable the listener to handle routing after arriving at the next page
    _userWorker = ever(user, navigateUserSignup);
  }

On my dashboard page:

@override
  initState() {
    super.initState();
    debugPrint('putting business controller');
    Get.put(
      BusinessController(Get.find<UserController>().authUser.value?.uid),
      permanent: true,
    );
  }

Is there perhaps something I am not properly marking to return the uid?