prefer_multi_bloc_provider

v0.4.0 Warning Fix Bloc / Riverpod

This rule flags nested BlocProvider, BlocListener, or RepositoryProvider widgets that could be consolidated using their Multi* counterpart. It only triggers when the same type is nested (e.g., BlocProvider inside BlocProvider), not when mixing different types.

Why use this rule

Deeply nested providers create a “pyramid of doom” that hurts readability and makes diffs harder to review. MultiBlocProvider, MultiBlocListener, and MultiRepositoryProvider flatten the nesting into a clean list, keeping the widget tree shallow and easy to scan. The behavior is identical — it’s purely a readability improvement.

See also: MultiBlocProvider | MultiBlocListener | MultiRepositoryProvider

Don’t

import 'package:flutter/widgets.dart';
import 'package:flutter_bloc/flutter_bloc.dart';

abstract class CounterEvent {}

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

class TimerCubit extends Cubit<int> {
  TimerCubit() : super(0);
}

// Nested BlocProviders
final widget = BlocProvider<CounterBloc>(
  create: (context) => CounterBloc(),
  child: BlocProvider<TimerCubit>(
    create: (context) => TimerCubit(),
    child: Container(),
  ),
);

Do

import 'package:flutter/widgets.dart';
import 'package:flutter_bloc/flutter_bloc.dart';

abstract class CounterEvent {}

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

class TimerCubit extends Cubit<int> {
  TimerCubit() : super(0);
}

// Flattened with MultiBlocProvider
final widget = MultiBlocProvider(
  providers: [
    BlocProvider<CounterBloc>(create: (context) => CounterBloc()),
    BlocProvider<TimerCubit>(create: (context) => TimerCubit()),
  ],
  child: Container(),
);

Configuration

This rule is in the opinionated preset, so it is on with preset: opinionated, or by name:

many_lints.yaml

rules:
  prefer_multi_bloc_provider: true

To turn it off again:

many_lints.yaml

rules:
  prefer_multi_bloc_provider: false

To keep the rule on but skip certain paths, use per-rule exclude.

Related rules

• avoid_bloc_public_methods — Prevent public methods, getters, and setters in Bloc classes.
• avoid_duplicate_bloc_event_handlers — Register each bloc event type exactly once.
• avoid_passing_bloc_to_bloc — Prevent Bloc/Cubit classes from depending on other Bloc/Cubit instances.
• emit_new_bloc_state_instances — Emit a new state instance instead of the existing state object.