[DataStore.Flutter] Android sourced mutation not working on iOS with schema

[lawmicha]

I was able to reproduce this with the following app, schema, and steps.

App

import 'package:amplify_api/amplify_api.dart';
import 'package:amplify_datastore/amplify_datastore.dart';
import 'package:amplify_flutter/amplify_flutter.dart';
import 'package:flutter/material.dart';
import 'package:issue_3654/amplifyconfiguration.dart';
import 'package:issue_3654/models/ModelProvider.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  void initState() {
    super.initState();
    _configureAmplify();
  }

  Future<void> _configureAmplify() async {
    final api = AmplifyAPI();
    final ds = AmplifyDataStore(modelProvider: ModelProvider.instance);
    await Amplify.addPlugins([api, ds]);

    try {
      await Amplify.configure(amplifyconfig);
    } on AmplifyAlreadyConfiguredException {
      safePrint(
          'Tried to reconfigure Amplify; this can occur when your app restarts on Android.');
    }

    observeQueryMessage();
  }

  void observeQueryMessage() {
    Amplify.DataStore.observeQuery(
      Message.classType,
    ).listen((QuerySnapshot<Message> snapshot) {
      safePrint(
        'Query snapshot received: ${snapshot.items.length} messages, isSynced: ${snapshot.isSynced}',
      );
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(useMaterial3: true),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  Future<void> saveMessage() async {
    safePrint("start saving message");
    User sender = User(
      email: 'example@gmail.com',
      birthdate: TemporalDate(DateTime.now()),
      gender: Gender.male,
      nickname: 'nickname',
    );

    await Amplify.DataStore.save(sender);

    CustomMarker circle = CustomMarker(
      latitude: 1.0,
      longitude: 1.0,
      hostUser: sender,
      purpose: Purpose.exchange,
      title: 'title',
      gatheringTime: TemporalDateTime(DateTime.now()),
      maxParticipants: 0,
      minAge: 0,
      maxAge: 0,
      numParticipants: 0,
    );

    await Amplify.DataStore.save(circle);

    Message message = Message(
      content: 'content',
      sender: sender,
      circle: circle,
      createdOn: TemporalDateTime(DateTime.now().toUtc()),
    );
    await Amplify.DataStore.save(message);
    safePrint('message saved');
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: const Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text('Hello world'),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: saveMessage,
        tooltip: 'save',
        child: const Icon(Icons.add),
      ),
    );
  }
}

Schema

enum Gender {
  male
  female
  other
}

enum UserStatus {
  student
  worker
  doctor
  other
}

type User
  @model
  @auth(
    rules: [{ allow: public, operations: [create, read, update, delete] }]
  ) {
  id: ID!
  email: String!
  phone: String
  birthdate: AWSDate!
  gender: Gender!
  userStatus: UserStatus
  nickname: String!
  comment: String
  imageURL: String
  messages: [Message] @hasMany(indexName: "MessageByUser", fields: ["id"])
  hostedCircles: [CustomMarker]
    @hasMany(indexName: "CustomMarkerByHostUser", fields: ["id"])
  participatedCircles: [CustomMarker]
    @manyToMany(relationName: "UserCustomMarkerParticipants")
}

enum Purpose {
  play
  food
  taxi
  exchange
  helpme
}

type CustomMarker @model @auth(rules: [{ allow: public }]) {
  id: ID!
  latitude: Float!
  longitude: Float!
  hostUserID: ID! @index(name: "CustomMarkerByHostUser")
  hostUser: User! @belongsTo(fields: ["hostUserID"])
  purpose: Purpose!
  title: String!
  comment: String
  gatheringTime: AWSDateTime!
  maxParticipants: Int!
  minAge: Int!
  maxAge: Int!
  allowGender: Gender
  numParticipants: Int!
  messages: [Message]
    @hasMany(indexName: "MessageByCustomMarker", fields: ["id"])
  participants: [User] @manyToMany(relationName: "UserCustomMarkerParticipants")
  circleImageURL: String
}

type Message @model @auth(rules: [{ allow: public }]) {
  id: ID!
  content: String!
  createdOn: AWSDateTime!
  senderID: ID! @index(name: "MessageByUser")
  sender: User! @belongsTo(fields: ["senderID"])
  circleID: ID! @index(name: "MessageByCustomMarker")
  circle: CustomMarker! @belongsTo(fields: ["circleID"])
}

Steps:

1. Save item on iOS, observe that Android receives the data
2. Save item on Android, observe that iOS does NOT receive data.

Note: If the app is closed/re-opened on iOS, the data does sync in the next delta sync.

Originally posted by @Jordan-Nelson in aws-amplify/amplify-flutter#3654 (comment)

[github-actions]

This issue was opened by a maintainer of this repository; updates will be posted here. If you are also experiencing this issue, please comment here with any relevant information so that we're aware and can prioritize accordingly.

[lawmicha]

To reproduce this, use the schema and create a backend with it and replay the requests using AppSync console if we have the selection set readily available (see aws-amplify/amplify-flutter#3654 (comment)). If not, create Flutter app using the sample code from description, and create a Swift app sharing the same backend, and perform saves sourced from the Android Flutter app, to observe the behavior on DataStore Swift v1 app.