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handle-bloc-event-subclasses

added in: 1.24.0
warning
⚙️
Free+

Warns when a bloc does not handle all event subclasses.

Usually, blocs are expected to handle all event subclasses or the event class itself.

⚙️ Config​

Set additional-methods (default is empty) to add additional methods used for listening to bloc events.

analysis_options.yaml
dart_code_metrics:
  rules:
    - handle-bloc-event-subclasses:
        additional-methods:
          - customOn

Example​

❌ Bad:

abstract class CounterEvent {}

class CounterIncrementEvent extends CounterEvent {}

class CounterDecrementEvent extends CounterEvent {}

class CounterBloc extends Bloc<CounterEvent, int> {
  // LINT: This bloc does not handle all event subclasses. Try adding missing event handlers or handle the parent event.
  CounterBloc() : super(0) {
    on<CounterIncrementEvent>(_handle);
  }

  Future<void> _handle(CounterEvent event, Emitter<int> emit) async {}
}

✅ Good:

class CorrectBloc extends Bloc<CounterEvent, int> {
  CorrectBloc() : super(0) {
    on<CounterIncrementEvent>(_handle);
    on<CounterDecrementEvent>(_handle);
  }

  Future<void> _handle(CounterEvent event, Emitter<int> emit) async {}
}

class CorrectBloc extends Bloc<CounterEvent, int> {
  CorrectBloc() : super(0) {
    on<CounterEvent>(_handle);
  }

  Future<void> _handle(CounterEvent event, Emitter<int> emit) async {}
}