Hilt - Dependency cycle crash

Question

If I just use the AuthRepository class in a single UseCase it's fine. However, if I try to use it in both AuthUseCase and RefreshTokenUseCase as in the example, I get an error.

Any suggestions other than using Lazy<> ?

Any help will be appreciated.

-

Error

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App_HiltComponents.java:139: error: [Dagger/DependencyCycle] Found a dependency cycle:
  public abstract static class SingletonC implements App_GeneratedInjector,
                         ^
      AppRepository is injected at
          RefreshTokenTokenUseCase(authRepository)
      RefreshTokenTokenUseCase is injected at
          AppAuthenticator(refreshTokenTokenUseCase)
          ......
          ...
          ..
      AuthUseCase(authRepository)
      AuthUseCase is injected at
          MainViewModel(authUseCase, …)
               MainViewModel is injected at
          MainViewModel_HiltModules.BindsModule.binds(vm)

My Code

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@Module
@InstallIn(SingletonComponent::class)
object NetworkModule {

    @Singleton
    @Provides
    fun provideRetrofit(): Retrofit =
        Retrofit.Builder()
            .baseUrl(Data.url)
            .addConverterFactory(GsonConverterFactory.create())
            .build()
}

@Module
@InstallIn(SingletonComponent::class)
object ApiModule {

    @Singleton
    @Provides
    fun provideAuthAPI(
        retrofit: Retrofit
    ): AuthAPI = retrofit.create(AuthAPI::class.java)
}


@Singleton
class AuthRepository @Inject constructor(
    private var authAPI: AuthAPI,
) {

}

@Singleton
class AuthUseCase @Inject constructor(
    private val authRepository: AuthRepository
) : UseCase<Response?, AuthUseCase.Params>() { 

}

@Singleton
class RefreshTokenUseCase @Inject constructor(
    private val authRepository: AuthRepository
) : UseCase<String?, RefreshTokenUseCase.Params>() { 

}

Answer 1

You can use Provider<T> instead of Lazy and than call .get() on it.

@Singleton
class RefreshTokenUseCase @Inject constructor(
    private val authRepositoryProvider: Provider<AuthRepository>
) : UseCase<String?, RefreshTokenUseCase.Params>() { 
    fun getRefreshToken() = authRepositoryProvider.get().getRefreshToken() //example of usage
}

This means RefreshTokenUseCase will be created before AuthRepository is created and later on it will receive singleton AuthRepository instance it needs. For more complete explanation check this SO post .