Bloc: After updating flutter to 1.17 and flutter_bloc to 4.0.0 the Bloc.transformEvents isn't valid override

[heshaShawky]

Describe the bug
After Updating the bloc library to 4.0.0 and flutter to 1.17 the VsCode throwing the following errors:

The code causing the error in the bloc:

@override
Stream<PostsState> transformEvents(Stream<PostsEvent> events,
    Stream<PostsState> Function(PostsEvent) next) {
  return super.transformEvents(
      events.debounceTime(const Duration(milliseconds: 300)), next);
}

'PostsBloc.transformEvents' ('Stream<PostsState> Function(Stream<PostsEvent>, Stream<PostsState> Function(PostsEvent))') isn't a valid override of 'Bloc.transformEvents' ('Stream<Transition<PostsEvent, PostsState>> Function(Stream<PostsEvent>, Stream<Transition<PostsEvent, PostsState>> Function(PostsEvent))').

The method 'debounceTime' isn't defined for the type 'Stream'.
Try correcting the name to the name of an existing method, or defining a method named 'debounceTime'.

The argument type 'Stream<PostsState> Function(PostsEvent)' can't be assigned to the parameter type 'Stream<Transition<PostsEvent, PostsState>> Function(PostsEvent)'.

Error one:

{
    "resource": "/Volumes/Partion-2/Projects/cars_time_mobile_app/lib/src/blocs/posts/posts_bloc.dart",
    "owner": "dart",
    "code": {
        "value": "invalid_override",
        "target": {
            "$mid": 1,
            "external": "https://dart.dev/tools/diagnostic-messages#invalid_override",
            "path": "/tools/diagnostic-messages",
            "scheme": "https",
            "authority": "dart.dev",
            "fragment": "invalid_override"
        }
    },
    "severity": 8,
    "message": "'PostsBloc.transformEvents' ('Stream<PostsState> Function(Stream<PostsEvent>, Stream<PostsState> Function(PostsEvent))') isn't a valid override of 'Bloc.transformEvents' ('Stream<Transition<PostsEvent, PostsState>> Function(Stream<PostsEvent>, Stream<Transition<PostsEvent, PostsState>> Function(PostsEvent))').",
    "source": "dart",
    "startLineNumber": 24,
    "startColumn": 22,
    "endLineNumber": 24,
    "endColumn": 37,
    "tags": []
}

Error two:

{
    "resource": "/Volumes/Partion-2/Projects/cars_time_mobile_app/lib/src/blocs/posts/posts_bloc.dart",
    "owner": "dart",
    "code": {
        "value": "undefined_method",
        "target": {
            "$mid": 1,
            "external": "https://dart.dev/tools/diagnostic-messages#undefined_method",
            "path": "/tools/diagnostic-messages",
            "scheme": "https",
            "authority": "dart.dev",
            "fragment": "undefined_method"
        }
    },
    "severity": 8,
    "message": "The method 'debounceTime' isn't defined for the type 'Stream'.\nTry correcting the name to the name of an existing method, or defining a method named 'debounceTime'.",
    "source": "dart",
    "startLineNumber": 27,
    "startColumn": 16,
    "endLineNumber": 27,
    "endColumn": 28,
    "tags": []
}

Last Error:

{
    "resource": "/Volumes/Partion-2/Projects/cars_time_mobile_app/lib/src/blocs/posts/posts_bloc.dart",
    "owner": "dart",
    "code": {
        "value": "argument_type_not_assignable",
        "target": {
            "$mid": 1,
            "external": "https://dart.dev/tools/diagnostic-messages#argument_type_not_assignable",
            "path": "/tools/diagnostic-messages",
            "scheme": "https",
            "authority": "dart.dev",
            "fragment": "argument_type_not_assignable"
        }
    },
    "severity": 8,
    "message": "The argument type 'Stream<PostsState> Function(PostsEvent)' can't be assigned to the parameter type 'Stream<Transition<PostsEvent, PostsState>> Function(PostsEvent)'.",
    "source": "dart",
    "startLineNumber": 27,
    "startColumn": 65,
    "endLineNumber": 27,
    "endColumn": 69,
    "tags": []
}

[felangel]

Hi @heshaShawky 👋
Thanks for opening an issue!

The signature updated to:

@override
Stream<Transition<PostsEvent, PostsState>> transformEvents(
  Stream<PostsEvent> events,
  TransitionFunction<PostsEvent, PostsState> transitionFn) {
  return super.transformEvents(
    events.debounceTime(const Duration(milliseconds: 300)),
    transitionFn,
  );
}

Hope that helps 👍