MergeInterfaces

Marks an interface to merge all contributed component interfaces for the given scope. This is a subset of what MergeComponent and MergeSubcomponent are doing.

This annotation is useful if you can't use MergeComponent and MergeSubcomponent directly for your Dagger component. The interface annotated with this annotation serves as a composite component interface.

@MergeInterfaces(AppScope::class)
interface CompositeAppComponent

One common scenario where this annotation is used is when you want to use javac and not KAPT for compiling your Dagger components. The recommendation there is to add an extra Gradle module that merges interfaces. Your Dagger component must manually extend this interface using this annotation.

// Gradle Module A.
@MergeInterfaces(AppScope::class)
interface CompositeAppComponent

// Gradle Module B, note that this is Java and not Kotlin.
@Component
public interface AppComponent extends CompositeAppComponent {}

It's possible to exclude any automatically added component interface with the exclude parameter if needed.

@MergeInterfaces(
    scope = AppScope::class,
    exclude = [
      ComponentInterface::class
    ]
)
interface CompositeAppComponent