Factory Generator (Koin)

The @GenerateFactory annotation triggers KSP code generation to create Koin dependency injection factory objects for Decompose components. This eliminates the need to manually wire Koin dependencies when creating components in navigation factories.

Usage

Annotate your component class with @GenerateFactory. Mark parameters that should be passed directly to the factory with @InjectedParam. All other constructor parameters are resolved from Koin automatically.

@GenerateFactory
class HomeComponent(
    @InjectedParam componentContext: AppComponentContext,
    @InjectedParam navigation: HomeNavigation,
    private val someUseCase: SomeUseCase, // resolved by Koin
) : BaseComponent<HomeState, HomeUiEvent>(componentContext, HomeState())

Generated Output

The annotation processor generates an internal object factory that implements KoinComponent:

internal object HomeComponentFactory : KoinComponent {
    fun createComponent(
        componentContext: AppComponentContext,
        navigation: HomeNavigation,
    ): HomeComponent = get(
        qualifier = null,
        parameters = { parametersOf(componentContext, navigation) },
    )
}

• Parameters marked with @InjectedParam become createComponent() parameters and are forwarded to Koin via parametersOf
• The component itself is resolved from Koin — it must be registered in your Koin module (typically as a factory)
• All non-@InjectedParam constructor dependencies (e.g. SomeUseCase) are resolved by Koin from the DI graph

// Koin module
val homeModule = module {
    factory { params ->
        HomeComponent(
            componentContext = params.get(),
            navigation = params.get(),
            someUseCase = get(),
        )
    }
}

Calling the Factory

Use the generated factory inside a nav-host's childStack child factory:

val stack = childStack(
    source = navigation.stackNavigator,
    serializer = AppDestination.serializer(),
    initialConfiguration = AppDestination.Home,
    childFactory = { destination, ctx ->
        when (destination) {
            AppDestination.Home -> HomeComponentFactory.createComponent(ctx, navigation)
            AppDestination.Detail -> DetailComponentFactory.createComponent(ctx, navigation)
        }
    },
).asStateFlow()

ctx is the child AppComponentContext provided by Decompose; navigation is the nav-host's navigation instance passed through as an @InjectedParam.

KSP Configuration for KMP

Important

Use kspCommonMainMetadata only. Do not add the processor to platform-specific configurations (kspAndroid, kspIosArm64, etc.) as this would cause duplicate generation.

Add the following to your module's build.gradle.kts:

plugins {
    id("com.google.devtools.ksp")
}

dependencies {
    add("kspCommonMainMetadata", "app.futured.arkitekt:decompose-processor:6.0.0-beta05")
}

kotlin.sourceSets.named("commonMain") {
    kotlin.srcDir("build/generated/ksp/metadata/commonMain/kotlin")
}

tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompilationTask<*>>().configureEach {
    if (name != "kspCommonMainKotlinMetadata") {
        dependsOn("kspCommonMainKotlinMetadata")
    }
}

This configuration ensures KSP runs on common metadata and the generated sources are available to all platform targets.