MergeSubcomponent

Dagger subcomponents that should automatically include Dagger modules and component interfaces for the given scope require this annotation instead of @Subcomponent. The Kotlin compiler plugin will add the @Subcomponent annotation to this interface. The modules parameter is preserved in the @Subcomponent annotation.

Imagine this module dependency tree:

           :app
         /   |
        v    |
    :lib-a   |
        \    |
         v   v
         :lib-b

:app creates the component with @MergeComponent, :lib-a creates a subcomponent with @MergeSubcomponent and :lib-b contributes a module to the scope of the subcomponent. This module will be included in the subcomponent because :lib-a depends on :lib-b.

:lib-a must depend on :lib-b because the subcomponent will only be able to pick up contributions within the scope of the containing Gradle module and is based on the module's compile classpath. This means the module must have a dependency on any modules that want to contribute to the subcomponent.

See ContributesSubcomponent for an alternative that eliminates the need for :lib-a to depend on :lib-b

@MergeSubcomponent(ActivityScope::class)
interface ActivitySubcomponent

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

@MergeSubcomponent(
    scope = ActivityScope::class,
    exclude = [
      DaggerModule::class,
      ComponentInterface::class
    ]
)
interface ActivitySubcomponent