Snapshot Listeners of converted documents don't pick up on changes to the same document if it's not also converted

[timcreatedit]

Since the typedSnapshotStreamKey depends on the type of a MockDocumentReference, there can be two separate snapshot stream keys for the same document reference if you obtain one from a converted collection and the other one from a non-converted one. This leads to changes not being picked up if you listen to the same document from a converted reference but modify it from a non-converted one.

I wrote a test to make it more understandable. The second test times out because the snapshot listener never emits the change

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:fake_cloud_firestore/fake_cloud_firestore.dart';
import 'package:flutter_test/flutter_test.dart';

class Model {
  const Model(this.name);

  factory Model.fromJson(Map<String, dynamic> data) => Model(data["name"]);

  final String name;

  Map<String, dynamic> toJson() => {"name": name};

  @override
  int get hashCode => Object.hash(runtimeType, name);

  @override
  operator ==(other) {
    return identical(this, other) || other is Model && other.name == name;
  }
}

void main() {
  late FakeFirebaseFirestore sut;
  late CollectionReference<Model> convertedCollection;
  late CollectionReference<Map<String, dynamic>> unconvertedCollection;

  const a = Model("a");
  const b = Model("b");

  setUp(() {
    sut = FakeFirebaseFirestore();
    convertedCollection = sut.collection("models").withConverter<Model>(
          fromFirestore: (snap, _) => Model.fromJson(snap.data()!),
          toFirestore: (value, _) => value.toJson(),
        );
    unconvertedCollection = sut.collection("models");
  });

  group('Incorrect snapshot listener behavior', () {
    test("this works", () async {
      await convertedCollection.doc("model").set(a);
      final stream = convertedCollection
          .doc("model")
          .snapshots()
          .map((event) => event.data());
      expectLater(stream, emitsInOrder([a, b]));
      convertedCollection.doc("model").set(b);
    });
    test("this fails", () async {
      await convertedCollection.doc("model").set(a);
      final stream = convertedCollection
          .doc("model")
          .snapshots()
          .map((event) => event.data());
      expectLater(stream, emitsInOrder([a, b]));
      unconvertedCollection.doc("model").set(b.toJson());
    });
  });
}
``

[LucaDillenburg]

Any updates on this?