How to Use Provider to solve the upgrade compatibility issue?

[malikwang]

The following code illustrates the compatibility issue

class MainModel extends ChangeNotifier {
  int _value = 0;

  void update() {
    _value += 1;
    notifyListeners();
  }

  int get value => _value;

  /// ...
}

class BaseComponentWidget extends StatelessWidget {
  const BaseComponentWidget({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Consumer<MainModel>(
      builder: (_, vm, __) {
        return Container(
          width: 100,
          height: 100,
          color: Colors.red,
          child: Text(vm.value.toString()),
        );
      },
    );
  }
}

If we upgrade the main model to another version, for example, MainModelV2. How to make the new model compatible with BaseComponentWidget ?
I use the following method to solve the problem, and it works.
But there are a few questions：

1. Is this an appropriate method?
2. A much better method?

/// first, define a abstract model for component
abstract class CompatibleModel with ChangeNotifier {
  int get value;
}

class CompatibleWidget extends StatelessWidget {
  const CompatibleWidget({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    /// the component only [consume] above model
    return Consumer<CompatibleModel>(
      builder: (_, vm, __) {
        return Container(
          width: 100,
          height: 100,
          color: Colors.red,
          child: Text(vm.value.toString()),
        );
      },
    );
  }
}

/// we only need the main model to implement the Property or Method which the component needs
class MainModelV1 extends ChangeNotifier implements CompatibleModel {
  int _value = 0;

  void update() {
    _value += 1;
    notifyListeners();
  }

  @override
  int get value => _value;

  /// ...
}

/// even update the main model
class MainModelV2 extends ChangeNotifier implements CompatibleModel {
  int _value = 0;

  void update() {
    _value += 1;
    notifyListeners();
  }

  @override
  int get value => _value;

  /// ...
}

full example:
https://github.com/malikwang/provider_compatibility
reference:

1. https://stackoverflow.com/questions/65405196/multiprovider-and-abstract-class
2. https://stackoverflow.com/questions/64487800/how-to-use-provider-with-base-class-in-flutter-dart?rq=1

[rrousselGit]

I don't understand the code given. What is it supposed to illustrate? It is not obvious to me.

[malikwang]

The problem is the small component(widget) [consume] the old model, which is not compatible with the future new model.
Maybe the design (consume the old mode) of this small component is unreasonable, but i cannot find a better solution.

[malikwang]

@rrousselGit u can delete this discussion