unable to register an abstract class in using injectable and get_it packages

Question

I'm using injectable and get_it in flutter dart (following the very popular Reso coder )

I have a simple abstract class:

import 'package:injectable/injectable.dart';

//@injectable
abstract class IRandomQuantityRepository {
  Future<int> getRandomQuantity();
}

and I have two simple concrete implementations of it:

import 'package:injectable/injectable.dart';

@dev
@injectable
class DevRandomQuantityRepository implements IRandomQuantityRepository {
  const DevRandomQuantityRepository();

  @override
  Future<int> getRandomQuantity() async => 90;
}

and

import 'dart:math';
import 'package:injectable/injectable.dart';

@prod
@injectable
class RandomQuantityRepository implements IRandomQuantityRepository {
  const RandomQuantityRepository();

  @override
  Future<int> getRandomQuantity() async => Random().nextInt(100);
}

Lastly, I have an injection.dart:

import 'package:get_it/get_it.dart';
import 'package:injectable/injectable.dart';
import 'package:moontreeapp/injection.config.dart';

final GetIt getIt = GetIt.instance;

@InjectableInit(preferRelativeImports: false)
void configureInjection(String env) {
  $initGetIt(getIt, environment: env);
}

abstract class Env {
  static const prod = 'prod';
  static const dev = 'dev';
}

besides all that I have a bloc that wants to use stuff:

@injectable
class RandomQuantityBloc
    extends Bloc<RandomQuantityEvent, RandomQuantityState> {
  final IRandomQuantityRepository _quantityFacade; // notice this final...

doesn't that look good? I think so. So then I run this command to make the generated code flutter pub run build_runner watch

But I get a message:

[RandomQuantityBloc] depends on unregistered type [IRandomQuantityRepository]... Did you forget to annotate the above class(s) or their implementation with @injectable? or add the right environment keys?

Ok, so that's cool, lets add it to the interface:

import 'package:injectable/injectable.dart';

@injectable // <-- added 
abstract class IRandomQuantityRepository {
  Future<int> getRandomQuantity();
}

but then I get a new error:

> [IRandomQuantityRepository] is abstract and can not be registered directly! 
> if it has a factory or a create method annotate it with @factoryMethod
> 14 │ abstract class IRandomQuantityRepository {
>    │                ^^^^^^^^^^^^^^^^^^^^^^^^^

In the past I've handled dependency injection manually, so I'm new to these packages, what am I missing here?

Besides all that, the real issue is that I can't switch the injection based on the environment. I can use get_it to get a concrete dependency but not one based on environment like in this test:

    /// has no effect:
    configureInjection(Env.dev);

    /// gets prod version:
    final devRandomQuantity = getIt<RandomQuantityRepository>();

So something about this whole set up isn't configuring the Injections correctly... What am I missing?

One final thing that might be useful is to see the generated code:

// GENERATED CODE - DO NOT MODIFY BY HAND

// **************************************************************************
// InjectableConfigGenerator
// **************************************************************************

import 'package:get_it/get_it.dart' as _i1;
import 'package:injectable/injectable.dart' as _i2;
import 'package:moontreeapp/application/quantity/bloc/randomquantity_bloc.dart'
    as _i5;
import 'package:moontreeapp/domain/quantity/i_randomquantity_repository.dart' as _i6;
import 'package:moontreeapp/infrastructure/quantity/dev_randomquantity_repository.dart'
    as _i3;
import 'package:moontreeapp/infrastructure/quantity/mock_randomquantity_repository.dart'
    as _i4;
import 'package:moontreeapp/infrastructure/quantity/randomquantity_repository.dart'
    as _i7;

const String _dev = 'dev';
const String _prod = 'prod';
// ignore_for_file: unnecessary_lambdas
// ignore_for_file: lines_longer_than_80_chars
/// initializes the registration of provided dependencies inside of [GetIt]
_i1.GetIt $initGetIt(_i1.GetIt get,
    {String? environment, _i2.EnvironmentFilter? environmentFilter}) {
  final gh = _i2.GetItHelper(get, environment, environmentFilter);
  gh.factory<_i3.DevRandomQuantityRepository>(
      () => _i3.DevRandomQuantityRepository(),
      registerFor: {_dev});
  gh.factory<_i5.RandomQuantityBloc>(
      () => _i5.RandomQuantityBloc(get<_i6.IRandomQuantityRepository>()));
  gh.factory<_i7.RandomQuantityRepository>(() => _i7.RandomQuantityRepository(),
      registerFor: {_prod});
  return get;
}

Do I put @injectable on abstract classes or not?

Answer 1

ok, so I guess injectable can't see what the class implements so you have to make it explicit. also, I missed that @dev isn't built in, you have to make it.

So this is the proper way to use the decorations

@Environment('dev')
@Injectable(as: IRandomQuantityRepository)
class DevRandomQuantityRepository implements IRandomQuantityRepository {
  const DevRandomQuantityRepository();

  @override
  Future<Either<QuantFailure, Quantity>> getRandomQuantity() async =>
      right(Quantity(Amount(900.0001), Decimal(4)));
}

and that way this does work:

configureInjection(Env.dev);
final mockRandomQuantity = getIt<IRandomQuantityRepository>();
await mockRandomQuantity.getRandomQuantity();
// 90