Support extending base builder classes

[Ralf Wondratschek]

This example for factories compiles fine:

interface BaseComponent {
  fun factory(): Factory

  interface Factory {
    fun create(@BindsInstance int: Int): BaseComponent
  }
}

@Subcomponent
interface SomeComponent : BaseComponent {
  override fun factory(): SomeComponent.Factory

  @Subcomponent.Factory
  interface Factory : BaseComponent.Factory {
    override fun create(@BindsInstance int: Int): SomeComponent
  }
}

Notice how I override all the base classes to the concrete types.

Changing the Factory to a Builder doesn't work and I don't see a reason why Dagger shouldn't support it:

interface BaseComponent {
  fun builder(): Builder

  interface Builder {
    @BindsInstance fun charSequence(sequence: CharSequence): Builder
    fun build(): BaseComponent
  }
}

@Subcomponent
interface SomeComponent : BaseComponent {
  override fun builder(): SomeComponent.Builder

  @Subcomponent.Builder
  interface Builder : BaseComponent.Builder {
    @BindsInstance override fun charSequence(sequence: CharSequence): SomeComponent.Builder
    override fun build(): SomeComponent
  }
}

Dagger throws several different errors depending on other changes. The first I run into is:

[Dagger/MissingBinding] java.lang.CharSequence cannot be provided without an @Provides-annotated method.

After stopping to rely on the binding I see this error:

DaggerParentComponent.SomeComponentBuilder is not abstract and does not override abstract method charSequence(CharSequence) in Builder
  private final class SomeComponentBuilder implements SomeComponent.Builder {

[Jake Wharton]

Wrong Dagger repo.

https://github.com/google/dagger

[Ralf Wondratschek]

Oh gosh...