Best practice: Unit test sample in README does not compile

[Sineaggi]

This code no longer compiles

class AppModel {}
class DbService {}

class UserManager {
  AppModel appModel;
  DbService dbService;

  UserManager({AppModel appModel, DbService dbService}) {
    this.appModel = appModel ?? getIt.get<AppModel>();
    this.dbService = dbService ?? getIt.get<DbService>();
  }
}

It complains with

Non-nullable instance field 'appModel' must be initialized.
Non-nullable instance field 'dbService' must be initialized.

Is it recommended to write every setup like this now, or is there another recommend way?

class UserManager {
  AppModel appModel;
  DbService dbService;

  UserManager({required this.appModel, required this.dbService});
}
getIt.registerFactory<AppModel>(() => AppModel());
getIt.registerFactory<DbService>(() => DbService());
getIt.registerFactory(() => UserManager(appModel: getIt<AppModel>(), dbService: getIt<DbService>()));

[Sineaggi]

Also, are there any general guidelines for how injected services should be named? Dart makes fields public by default, which means someone could feasibly call functions on one of those injected fields.

class AppModel{}
class DbService{}
class UserManager {
  AppModel appModel;
  DbService dbService;
  UserManager(this.appModel, this.dbService);
}

void test() {
  final userManager = UserManager(AppModel(), DbService());
  userManager.appModel.someFunction(); //  the function that shouldn't be exposed from the UserManager
}

[Sineaggi]

Maybe something like this?

class AppModel{}
class DbService{}
class UserManager {
  final AppModel _appModel;
  final DbService _dbService;
  UserManager._(this._appModel, this._dbService);
  factory UserManager({required AppModel appModel, required DbService dbService}) => UserManager._(appModel, dbService);
}

void test() {
  final userManager = UserManager(appModel: AppModel(), dbService: DbService());
  userManager.appModel.someFunction(); // no longer compiles
}

[escamoteur]

Hi, sorry for not looking into this earlier, but I had some mental health problems the last half year.

Sorry, you are right. After null safety that parameters should be either "required" but that's not what you wan't. you have to declare them nullable

class UserManager {
  AppModel appModel;
  DbService dbService;

  UserManager({AppModel? appModel, DbService? dbService}) {
    this.appModel = appModel ?? getIt.get<AppModel>();
    this.dbService = dbService ?? getIt.get<DbService>();
  }
}

[escamoteur]

does that help?

[Sineaggi]

Sorry, what do you mean by

After null safety that parameters should be either "required" but that's not what you wan't.

Is the use of required a problem?

[escamoteur]

when you add required you have always to manually inject the dependencies so it wouldn't make any sense to additionally request them from get_it