Scale your Kotlin Multiplatform projects using dependency injection

Kotlin-inject-anvil is a dependency injection framework for Kotlin Multiplatform. It verifies the dependency graph at compile time and generates the necessary code to instantiate the object graph at runtime. The framework aims to provide a safe dependency injection solution without the boilerplate and configurations common in many other libraries.

This talk will introduce kotlin-inject-anvil, discussing its benefits and how it scales in large, modularized codebases. We'll explore how to leverage the strengths of each host platform while maximizing common Kotlin Multiplatform code. Since each codebase is unique, I'll demonstrate how we adapt the framework for our own internal use cases at Amazon.

Transcript

1. Scale your Kotlin Multiplatform projects using dependency injection May 23rd, 2025 Ralf Wondratschek
2. Scale your KMP projects using dependency injection Ralf Wondratschek ralf-wondratschek.com
3. https://www.youtube.com/watch?v=xESX82kwjn4
5. https://www.youtube.com/watch?v=0T_zvUEqsD4 https://www.youtube.com/watch?v=0T_zvUEqsD4
9. Background • Adopted KMP for new initiatives in 2024 • Shared APIs • Shared or distinct implementations • Common architecture for shared features
10. Background https://amzn.github.io/app-platform
11. Background https://ralf-wondratschek.com/presentations
12. Background • On Android we used Dagger 2 and Anvil ◦ We like Dagger 2 for its safety checks and runtime speed ◦ We like Anvil for its simplicity
13. Dagger 2 :weather:impl-phone :weather:impl-van :weather:impl-jvm :weather:public :app:van :app:jvm :app:phone
14. Anvil interface WeatherRepository { fun provideForecast(location: Location): Forecast } @Singleton @ContributesBinding(AppScope::class) class WeatherRepositoryImpl @Inject constructor( client: HttpClient, ) : WeatherRepository
15. Background • On Android we used Dagger 2 and Anvil ◦ We like Dagger 2 for its safety checks and runtime speed ◦ We like Anvil for its simplicity
16. Background • On Android we used Dagger 2 and Anvil ◦ We like Dagger 2 for its safety checks and runtime speed ◦ We like Anvil for its simplicity • But both don’t work with KMP in common code
17. Dependency Inversion Dependency inversion is a design principle to reduce coupling between components. It means that high-level APIs don’t depend on low-level details and low-level details only import other high-level APIs.
18. Dependency Inversion interface WeatherRepository { fun provideForecast(location: Location): Forecast } class WeatherRepositoryImpl( ... ) : WeatherRepository { ... } class WeatherReport( weatherRepository: WeatherRepository, )
19. Dependency Inversion interface WeatherRepository { fun provideForecast(location: Location): Forecast } class WeatherRepositoryImpl( ... ) : WeatherRepository { ... } class WeatherReport( weatherRepository: WeatherRepository, )
20. Dependency Injection Dependency injection is a design principle where objects and classes receive dependencies rather than creating and managing them themselves. This principle reduces coupling and improves testability.
21. Dependency Injection class WeatherReport { val weatherRepository: WeatherRepository = WeatherRepositoryImpl() }
22. Dependency Injection class WeatherReport( val weatherRepository: WeatherRepository, ) { ... }
23. Do we need a framework?
24. Do we need a framework? interface WeatherRepository class WeatherRepositoryImpl : WeatherRepository class WeatherReport( val weatherRepository: WeatherRepository, )
25. Do we need a framework? fun showWeatherReport() { val weatherRepository: WeatherRepository = WeatherRepositoryImpl() val weatherReport = WeatherReport(weatherRepository) }
26. Do we need a framework? object Component { val weatherRepository: WeatherRepository = WeatherRepositoryImpl() val weatherReport = WeatherReport(weatherRepository) } fun showWeatherReport() { Component.weatherReport }
27. Do we need a framework? interface LocationProvider class RealTimeLocationProvider : LocationProvider class WeatherRepositoryImpl( locationProvider: LocationProvider, ) : WeatherRepository
28. Do we need a framework? object Component { val weatherRepository: WeatherRepository = WeatherRepositoryImpl() val weatherReport = WeatherReport(weatherRepository) } fun showWeatherReport() { Component.weatherReport }
29. Do we need a framework? object Component { val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) val weatherReport = WeatherReport(weatherRepository) } fun showWeatherReport() { Component.weatherReport }
30. Do we need a framework? object Component { val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) val weatherReport = WeatherReport(weatherRepository, locationProvider) } fun showWeatherReport() { Component.weatherReport }
31. Problems • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • …
32. Service locator class Component { private val services = mutableMapOf<KClass<*>, Any>() fun <T : Any> register(clazz: KClass<T>, dependency: T) { services[clazz] = dependency } fun <T : Any> get(clazz: KClass<T>): T { @Suppress("UNCHECKED_CAST") return services.getValue(clazz) as T } inline fun <reified T: Any> get(): T = get(T::class) }
33. Service locator fun main() { val component = Component() component.register(LocationProvider::class, RealTimeLocationProvider()) component.register(WeatherRepository::class, WeatherRepositoryImpl(component.get())) component.register(WeatherReport::class, WeatherReport(component.get(), component.get())) }
34. Service locator fun main() { val component = Component() component.register(LocationProvider::class, RealTimeLocationProvider()) component.register(WeatherRepository::class, WeatherRepositoryImpl(component.get())) component.register(WeatherReport::class, WeatherReport(component.get(), component.get())) }
35. Service locator fun main() { val component = Component().apply { register(LocationProvider::class, RealTimeLocationProvider()) register(WeatherRepository::class, WeatherRepositoryImpl(get())) register(WeatherReport::class, WeatherReport(get(), get())) } }
36. Service locator fun main() { val component = Component().apply { register(LocationProvider::class, RealTimeLocationProvider()) register(WeatherRepository::class, WeatherRepositoryImpl(get())) register(WeatherReport::class, WeatherReport(get(), get())) } }
37. Service locator // :weather-report fun setupWeatherReportDependencies(component: Component) { component.register(WeatherReport::class, WeatherReport(component.get(), component.get())) }
38. Service locator fun showWeatherReport(component: Component) { component.get<WeatherReport>() }
39. Problems • No compile time safety • No circular dependency detection • Race conditions • Boilerplate • Service locator
40. Invoke constructors // :weather-report fun setupWeatherReportDependencies(component: Component) { component.register(WeatherReport::class, WeatherReport(component.get(), component.get())) }
41. Invoke constructors // :weather-report fun setupWeatherReportDependencies(component: Component) { component.register(WeatherReport::class, WeatherReport(component.get(), component.get())) }
42. Invoke constructors dependencies { implementation "org.jetbrains.kotlin:kotlin-reflect" }
43. Invoke constructors @Target(CONSTRUCTOR, CLASS) annotation class Inject
44. Invoke constructors class Component { fun <T : Any> get(clazz: KClass<T>): T { @Suppress("UNCHECKED_CAST") return services.getOrPut(clazz) { instantiate(clazz) } as T } private fun <T : Any> instantiate(clazz: KClass<T>): T { val constructor = clazz.constructors .singleOrNull { it.hasAnnotation<Inject>() } ?: checkNotNull(clazz.primaryConstructor) val arguments = constructor.parameters.map { parameter -> get(parameter.type.classifier as KClass<*>) } return constructor.call(*arguments.toTypedArray()) } }
45. Invoke constructors class Component { fun <T : Any> get(clazz: KClass<T>): T { @Suppress("UNCHECKED_CAST") return services.getOrPut(clazz) { instantiate(clazz) } as T } private fun <T : Any> instantiate(clazz: KClass<T>): T { val constructor = clazz.constructors .singleOrNull { it.hasAnnotation<Inject>() } ?: checkNotNull(clazz.primaryConstructor) val arguments = constructor.parameters.map { parameter -> get(parameter.type.classifier as KClass<*>) } return constructor.call(*arguments.toTypedArray()) } }
46. Invoke constructors class Component { fun <T : Any> get(clazz: KClass<T>): T { @Suppress("UNCHECKED_CAST") return services.getOrPut(clazz) { instantiate(clazz) } as T } private fun <T : Any> instantiate(clazz: KClass<T>): T { val constructor = clazz.constructors .singleOrNull { it.hasAnnotation<Inject>() } ?: checkNotNull(clazz.primaryConstructor) val arguments = constructor.parameters.map { parameter -> get(parameter.type.classifier as KClass<*>) } return constructor.call(*arguments.toTypedArray()) } }
47. Invoke constructors class Component { fun <T : Any> get(clazz: KClass<T>): T { @Suppress("UNCHECKED_CAST") return services.getOrPut(clazz) { instantiate(clazz) } as T } private fun <T : Any> instantiate(clazz: KClass<T>): T { val constructor = clazz.constructors .singleOrNull { it.hasAnnotation<Inject>() } ?: checkNotNull(clazz.primaryConstructor) val arguments = constructor.parameters.map { parameter -> get(parameter.type.classifier as KClass<*>) } return constructor.call(*arguments.toTypedArray()) } }
48. Invoke constructors class Component { fun <T : Any> get(clazz: KClass<T>): T { @Suppress("UNCHECKED_CAST") return services.getOrPut(clazz) { instantiate(clazz) } as T } private fun <T : Any> instantiate(clazz: KClass<T>): T { val constructor = clazz.constructors .singleOrNull { it.hasAnnotation<Inject>() } ?: checkNotNull(clazz.primaryConstructor) val arguments = constructor.parameters.map { parameter -> get(parameter.type.classifier as KClass<*>) } return constructor.call(*arguments.toTypedArray()) } }
49. Invoke constructors class RealTimeLocationProvider : LocationProvider class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository class WeatherReport( val weatherRepository: WeatherRepository, val locationProvider: LocationProvider, )
50. Invoke constructors @Inject class RealTimeLocationProvider : LocationProvider @Inject class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository @Inject class WeatherReport( val weatherRepository: WeatherRepository, val locationProvider: LocationProvider, )
51. Invoke constructors fun main() { val component = Component() component.get<WeatherReport>() }
52. Invoke constructors fun main() { val component = Component() component.get<WeatherReport>() } java.lang.IllegalStateException: Required value was null. at software.amazon.lastmile.kotlin.inject.anvil.sample.Component.instantiate(AndroidAppComponent.kt:75) at software.amazon.lastmile.kotlin.inject.anvil.sample.Component.get(AndroidAppComponent.kt:65) at software.amazon.lastmile.kotlin.inject.anvil.sample.Component.instantiate(AndroidAppComponent.kt:78) at software.amazon.lastmile.kotlin.inject.anvil.sample.Component.get(AndroidAppComponent.kt:65)
53. Invoke constructors fun main() { val component = Component().apply { register(LocationProvider::class, get<RealTimeLocationProvider>()) register(WeatherRepository::class, get<WeatherRepositoryImpl>()) } component.get<WeatherReport>() }
54. Invoke constructors fun main() { val component = Component().apply { bind<LocationProvider, RealTimeLocationProvider>() bind<WeatherRepository, WeatherRepositoryImpl>() } component.get<WeatherReport>() }
55. Problems service locator • No compile time safety • No circular dependency detection • Race conditions • Boilerplate (a little less) • Service locator
56. Problems service locator • No compile time safety • No circular dependency detection • Race conditions • Boilerplate (a little less) • Service locator • JVM / Android only • Runtime overhead
57. Problems service locator object Component { val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) val weatherReport = WeatherReport(weatherRepository, locationProvider) } fun showWeatherReport() { Component.weatherReport }
58. Combined solution • No compile time safety • No circular dependency detection • Race conditions • Boilerplate (a little less) • Service locator • JVM / Android only • Runtime overhead • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • Invoke constructors automatically
59. Combined solution • No compile time safety • No circular dependency detection • Race conditions • Boilerplate • Service locator • JVM / Android only • Runtime overhead • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • Invoke constructors automatically
60. Replacing dependencies in tests object Component { val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) val weatherReport = WeatherReport(weatherRepository, locationProvider) }
61. Replacing dependencies in tests class Component( val locationProvider: LocationProvider = RealTimeLocationProvider(), ) { val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) val weatherReport = WeatherReport(weatherRepository, locationProvider) }
62. Replacing dependencies in tests class Component( val locationProvider: LocationProvider = RealTimeLocationProvider(), val weatherReport: WeatherReport = WeatherReport(weatherRepository, locationProvider) ) { val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) }
63. Replacing dependencies in tests interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } class AppComponent : BaseComponent { override val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { override val locationProvider: LocationProvider = FakeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) }
64. Replacing dependencies in tests interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } class AppComponent : BaseComponent { override val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { override val locationProvider: LocationProvider = FakeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) }
65. Combined solution • No compile time safety • No circular dependency detection • Race conditions • Boilerplate • Service locator • JVM / Android only • Runtime overhead • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • Invoke constructors automatically
66. Combined solution • No compile time safety • No circular dependency detection • Race conditions • Boilerplate • Service locator • JVM / Android only • Runtime overhead • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • Invoke constructors automatically
67. Scopes with shorter lifecycle App lifetime
68. Scopes with shorter lifecycle App Scope App lifetime
69. Scopes with shorter lifecycle App Scope App lifetime Logged-in Scope
70. Scopes with shorter lifecycle App Scope App lifetime Logged-in Scope Logged-in Scope
71. Scopes with shorter lifecycle App Scope App lifetime Logged-in Scope Logged-in Scope On-duty Scope
72. Scopes with shorter lifecycle class AppComponent { val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) val weatherReport = WeatherReport(weatherRepository, locationProvider) }
73. Scopes with shorter lifecycle class AppComponent { val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
74. Scopes with shorter lifecycle class AppComponent { val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
75. Combined solution • No compile time safety • No circular dependency detection • Race conditions • Boilerplate • Service locator • JVM / Android only • Runtime overhead • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • Invoke constructors automatically
76. Combined solution • No compile time safety • No circular dependency detection • Race conditions • Boilerplate • Service locator • JVM / Android only • Runtime overhead • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • Invoke constructors automatically
77. Adding classes we don’t own class AppComponent { val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
78. Adding classes we don’t own class AppComponent { val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
79. Combined solution • No compile time safety • No circular dependency detection • Race conditions • Boilerplate • Service locator • JVM / Android only • Runtime overhead • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • Invoke constructors automatically
80. Combined solution • No compile time safety • No circular dependency detection • Race conditions • Boilerplate • Service locator • JVM / Android only • Runtime overhead • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • Invoke constructors automatically
81. Boilerplate interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } class AppComponent : BaseComponent { override val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { override val locationProvider: LocationProvider = FakeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
82. Boilerplate - invoke constructors interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } class AppComponent : BaseComponent { override val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { override val locationProvider: LocationProvider = FakeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
83. Boilerplate - invoke constructors interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } class AppComponent : BaseComponent { override val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { override val locationProvider: LocationProvider = FakeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
84. Boilerplate interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } class AppComponent : BaseComponent { override val locationProvider: LocationProvider = RealTimeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { override val locationProvider: LocationProvider = FakeLocationProvider() val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
85. Boilerplate interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } class AppComponent : BaseComponent { fun bind(locationProvider: RealTimeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { fun bind(locationProvider: FakeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
86. Boilerplate - invoke constructors interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } class AppComponent : BaseComponent { fun bind(locationProvider: RealTimeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { fun bind(locationProvider: FakeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
87. Boilerplate interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } class AppComponent : BaseComponent { fun bind(locationProvider: RealTimeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { fun bind(locationProvider: FakeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
88. Boilerplate interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport fun bind(weatherRepository: WeatherRepositoryImpl): WeatherRepository } class AppComponent : BaseComponent { fun bind(locationProvider: RealTimeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { fun bind(locationProvider: FakeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
89. Boilerplate - invoke constructors interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport fun bind(weatherRepository: WeatherRepositoryImpl): WeatherRepository } class AppComponent : BaseComponent { fun bind(locationProvider: RealTimeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { fun bind(locationProvider: FakeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { val savedLocations: SavedLocations = SavedLocationsImpl(appComponent.locationProvider) }
90. Boilerplate - invoke constructors interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport fun bind(weatherRepository: WeatherRepositoryImpl): WeatherRepository } class AppComponent : BaseComponent { fun bind(locationProvider: RealTimeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { fun bind(locationProvider: FakeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { fun bind(savedLocations: SavedLocationsImpl): SavedLocations }
91. Combined solution • No compile time safety • No circular dependency detection • Race conditions • Boilerplate • Service locator • JVM / Android only • Runtime overhead • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • Invoke constructors automatically
92. Combined solution • No compile time safety • No circular dependency detection • Race conditions • Boilerplate • Service locator • JVM / Android only • Runtime overhead • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • Invoke constructors automatically
93. Boilerplate - bindings interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport fun bind(weatherRepository: WeatherRepositoryImpl): WeatherRepository } class AppComponent : BaseComponent { fun bind(locationProvider: RealTimeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { fun bind(locationProvider: FakeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { fun bind(savedLocations: SavedLocationsImpl): SavedLocations }
94. Boilerplate - bindings @Inject class RealTimeLocationProvider : LocationProvider @Inject class FakeLocationProvider : LocationProvider @Inject class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository
95. Boilerplate - bindings @Inject @ContributesBinding class RealTimeLocationProvider : LocationProvider @Inject @ContributesBinding class FakeLocationProvider : LocationProvider @Inject @ContributesBinding class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository
96. Boilerplate - bindings @Inject @ContributesBinding class RealTimeLocationProvider : LocationProvider @Inject @ContributesBinding(replaces = RealTimeLocationProvider::class) class FakeLocationProvider : LocationProvider @Inject @ContributesBinding class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository
97. Boilerplate - bindings interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport fun bind(weatherRepository: WeatherRepositoryImpl): WeatherRepository } class AppComponent : BaseComponent { fun bind(locationProvider: RealTimeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { fun bind(locationProvider: FakeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { fun bind(savedLocations: SavedLocationsImpl): SavedLocations }
98. Boilerplate - bindings interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport fun bind(weatherRepository: WeatherRepositoryImpl): WeatherRepository } class AppComponent : BaseComponent { fun bind(locationProvider: RealTimeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { fun bind(locationProvider: FakeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class LoggedInComponent( appComponent: AppComponent, authToken: String, ) { fun bind(savedLocations: SavedLocationsImpl): SavedLocations }
99. Boilerplate - component interfaces interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport fun bind(weatherRepository: WeatherRepositoryImpl): WeatherRepository } class AppComponent : BaseComponent { fun bind(locationProvider: RealTimeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } class TestComponent : BaseComponent { fun bind(locationProvider: FakeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) }
100. Boilerplate - component interfaces @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport fun bind(weatherRepository: WeatherRepositoryImpl): WeatherRepository } @MergeComponent(AppScope::class) class AppComponent : BaseComponent { fun bind(locationProvider: RealTimeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } @MergeComponent(AppScope::class) class TestComponent : BaseComponent { fun bind(locationProvider: FakeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) }
101. Boilerplate - component interfaces @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport fun bind(weatherRepository: WeatherRepositoryImpl): WeatherRepository } @MergeComponent(AppScope::class) class AppComponent { fun bind(locationProvider: RealTimeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) } @MergeComponent(AppScope::class) class TestComponent { fun bind(locationProvider: FakeLocationProvider): LocationProvider val weatherRepository: WeatherRepository = WeatherRepositoryImpl(locationProvider) override val weatherReport = WeatherReport(weatherRepository, locationProvider) }
102. Boilerplate - component interfaces @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) class AppComponent @MergeComponent(AppScope::class) class TestComponent class LoggedInComponent( appComponent: AppComponent, authToken: String, )
103. Combined solution • No compile time safety • No circular dependency detection • Race conditions • Boilerplate • Service locator • JVM / Android only • Runtime overhead • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • Invoke constructors automatically
104. Combined solution • No compile time safety • No circular dependency detection • Race conditions • Boilerplate • Service locator • JVM / Android only • Runtime overhead • Replacing dependencies in tests • Scopes with shorter lifecycle • Adding classes we don’t own • Component needs to be updated frequently (high maintenance) • Component needs to live in the application modules (duplication) • Invoke constructors automatically
105. Boilerplate - meta programming - KSP @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) class AppComponent @MergeComponent(AppScope::class) class TestComponent class LoggedInComponent( appComponent: AppComponent, authToken: String, )
106. @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) interface AppComponent @MergeComponent(AppScope::class) interface TestComponent abstract class LoggedInComponent( appComponent: AppComponent, authToken: String, ) Boilerplate - meta programming - KSP
107. @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) interface AppComponent Boilerplate - meta programming - KSP
108. Boilerplate - meta programming - KSP @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) interface AppComponent
109. Boilerplate - meta programming - KSP @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) interface AppComponent class FinalAppComponent : AppComponent { }
110. Boilerplate - meta programming - KSP @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) interface AppComponent class FinalAppComponent : AppComponent, BaseComponent { }
111. Boilerplate - meta programming - KSP @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) interface AppComponent class FinalAppComponent : AppComponent, BaseComponent { override val locationProvider: LocationProvider = ??? override val weatherReport: WeatherReport = ??? }
112. Boilerplate - meta programming - KSP @Inject @ContributesBinding class RealTimeLocationProvider : LocationProvider @MergeComponent(AppScope::class) interface AppComponent class FinalAppComponent : AppComponent, BaseComponent { override val locationProvider: LocationProvider = RealTimeLocationProvider() override val weatherReport: WeatherReport = ??? }
113. Boilerplate - meta programming - KSP @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) interface AppComponent class FinalAppComponent : AppComponent, BaseComponent { override val locationProvider: LocationProvider = RealTimeLocationProvider() override val weatherReport: WeatherReport = WeatherReport( weatherRepository = ???, locationProvider = ???, ) }
114. Boilerplate - meta programming - KSP @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) interface AppComponent class FinalAppComponent : AppComponent, BaseComponent { override val locationProvider: LocationProvider = RealTimeLocationProvider() override val weatherReport: WeatherReport = WeatherReport( weatherRepository = ???, locationProvider = locationProvider, ) }
115. Boilerplate - meta programming - KSP @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) interface AppComponent class FinalAppComponent : AppComponent, BaseComponent { override val locationProvider: LocationProvider = RealTimeLocationProvider() private val weatherRepository: WeatherRepository = ??? override val weatherReport: WeatherReport = WeatherReport( weatherRepository = weatherRepository, locationProvider = locationProvider, ) }
116. Boilerplate - meta programming - KSP @Inject @ContributesBinding class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository @MergeComponent(AppScope::class) interface AppComponent class FinalAppComponent : AppComponent, BaseComponent { override val locationProvider: LocationProvider = RealTimeLocationProvider() private val weatherRepository: WeatherRepository = WeatherRepositoryImpl( locationProvider = ???, ) override val weatherReport: WeatherReport = WeatherReport( weatherRepository = weatherRepository, locationProvider = locationProvider, ) }
117. Boilerplate - meta programming - KSP @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) interface AppComponent class FinalAppComponent : AppComponent, BaseComponent { override val locationProvider: LocationProvider = RealTimeLocationProvider() private val weatherRepository: WeatherRepository = WeatherRepositoryImpl( locationProvider = locationProvider, ) override val weatherReport: WeatherReport = WeatherReport( weatherRepository = weatherRepository, locationProvider = locationProvider, ) }
118. kotlin-inject-anvil
119. kotlin-inject kotlin-inject is a compile-time dependency injection (DI) framework designed specifically for Kotlin. https://github.com/evant/kotlin-inject
120. kotlin-inject-anvil kotlin-inject-anvil is an extension library kotlin-inject, designed to enhance its functionality by incorporating features inspired by Square’s Anvil library. https://github.com/amzn/kotlin-inject-anvil
121. Prototype @Inject @ContributesBinding class RealTimeLocationProvider : LocationProvider @Inject @ContributesBinding(replaces = RealTimeLocationProvider::class) class FakeLocationProvider : LocationProvider @Inject @ContributesBinding class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository
122. kotlin-inject-anvil import me.tatarka.inject.annotations.Inject import software.amazon.lastmile.kotlin.inject.anvil.AppScope import software.amazon.lastmile.kotlin.inject.anvil.ContributesBinding import software.amazon.lastmile.kotlin.inject.anvil.SingleIn @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class RealTimeLocationProvider : LocationProvider @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class, replaces = [RealTimeLocationProvider::class]) class FakeLocationProvider : LocationProvider @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository
123. kotlin-inject-anvil import me.tatarka.inject.annotations.Inject import software.amazon.lastmile.kotlin.inject.anvil.AppScope import software.amazon.lastmile.kotlin.inject.anvil.ContributesBinding import software.amazon.lastmile.kotlin.inject.anvil.SingleIn @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class RealTimeLocationProvider : LocationProvider @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class, replaces = [RealTimeLocationProvider::class]) class FakeLocationProvider : LocationProvider @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository
124. kotlin-inject-anvil import me.tatarka.inject.annotations.Inject import software.amazon.lastmile.kotlin.inject.anvil.AppScope import software.amazon.lastmile.kotlin.inject.anvil.ContributesBinding import software.amazon.lastmile.kotlin.inject.anvil.SingleIn @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class RealTimeLocationProvider : LocationProvider @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class, replaces = [RealTimeLocationProvider::class]) class FakeLocationProvider : LocationProvider @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository
125. kotlin-inject-anvil import me.tatarka.inject.annotations.Inject import software.amazon.lastmile.kotlin.inject.anvil.AppScope import software.amazon.lastmile.kotlin.inject.anvil.ContributesBinding import software.amazon.lastmile.kotlin.inject.anvil.SingleIn @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class RealTimeLocationProvider : LocationProvider @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class, replaces = [RealTimeLocationProvider::class]) class FakeLocationProvider : LocationProvider @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository
126. kotlin-inject-anvil object LoggedInScope
127. kotlin-inject-anvil object LoggedInScope interface SavedLocations @Inject @SingleIn(LoggedInScope::class) @ContributesBinding(LoggedInScope::class) class SavedLocationsImpl( val locationProvider: LocationProvider, ) : SavedLocations
128. Prototype @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @MergeComponent(AppScope::class) interface AppComponent @MergeComponent(AppScope::class) interface TestComponent abstract class LoggedInComponent( appComponent: AppComponent, authToken: String, )
129. kotlin-inject-anvil import software.amazon.lastmile.kotlin.inject.anvil.* @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @SingleIn(AppScope::class) @MergeComponent(AppScope::class) interface AppComponent @SingleIn(AppScope::class) @MergeComponent(AppScope::class) interface TestComponent @SingleIn(LoggedInScope::class) @MergeComponent(LoggedInScope::class) abstract class LoggedInComponent( @Component val appComponent: AppComponent, authToken: String, )
130. kotlin-inject-anvil import software.amazon.lastmile.kotlin.inject.anvil.* @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @SingleIn(AppScope::class) @MergeComponent(AppScope::class) interface AppComponent @SingleIn(AppScope::class) @MergeComponent(AppScope::class) interface TestComponent @SingleIn(LoggedInScope::class) @MergeComponent(LoggedInScope::class) abstract class LoggedInComponent( @Component val appComponent: AppComponent, authToken: String, )
131. kotlin-inject-anvil import software.amazon.lastmile.kotlin.inject.anvil.* @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @SingleIn(AppScope::class) @MergeComponent(AppScope::class) interface AppComponent @SingleIn(AppScope::class) @MergeComponent(AppScope::class) interface TestComponent @SingleIn(LoggedInScope::class) @MergeComponent(LoggedInScope::class) abstract class LoggedInComponent( @Component val appComponent: AppComponent, authToken: String, )
132. kotlin-inject-anvil import software.amazon.lastmile.kotlin.inject.anvil.* @ContributesTo(AppScope::class) interface BaseComponent { val locationProvider: LocationProvider val weatherReport: WeatherReport } @SingleIn(AppScope::class) @MergeComponent(AppScope::class) interface AppComponent @SingleIn(AppScope::class) @MergeComponent(AppScope::class) interface TestComponent @SingleIn(LoggedInScope::class) @MergeComponent(LoggedInScope::class) abstract class LoggedInComponent( @Component val appComponent: AppComponent, authToken: String, )
133. kotlin-inject-anvil // src/commonMain @SingleIn(AppScope::class) @MergeComponent(AppScope::class) interface AppComponent
134. kotlin-inject-anvil // src/commonMain @SingleIn(AppScope::class) @MergeComponent(AppScope::class) interface AppComponent @CreateComponent expect fun KClass<AppComponent>.createComponent(): AppComponent
135. kotlin-inject-anvil // src/commonMain @SingleIn(AppScope::class) @MergeComponent(AppScope::class) interface AppComponent @CreateComponent expect fun KClass<AppComponent>.createComponent(): AppComponent // generated/ksp/android // generated/ksp/iosArm64 // generated/ksp/iosSimulatorArm64 // … class KotlinInjectAppComponent : AppComponent https://kotlinlang.org/docs/whatsnew20.html#separation-of-common-and-platform-sources-during-compilation
136. kotlin-inject-anvil fun main() { val appComponent = AppComponent::class.createComponent() }
137. kotlin-inject-anvil - features • Provider methods • Qualifiers • Multi-bindings • Assisted injection • Lazy injection • Default argument support • Overridable provider methods • Child components • Component arguments
138. kotlin-inject-anvil - benefits • KMP support • Compile time safety • Little to no boilerplate • Aligns build graph with Gradle dependency graph • Easy to replace bindings in tests • Extensible with custom code generators
139. kotlin-inject-anvil - critique • No wide adoption • Slower build times compared to vanilla Kotlin due to KSP • Learning curve • Unclear error messages
140. kotlin-inject-anvil - our setup
141. kotlin-inject-anvil - our setup https://amzn.github.io/app-platform
142. kotlin-inject-anvil - our setup :phone-android-app
143. kotlin-inject-anvil - our setup :phone-android-app :phone-ios-umbrella /iosPhoneProject
144. kotlin-inject-anvil - our setup :phone-android-app :van-app :phone-ios-umbrella /iosPhoneProject
145. kotlin-inject-anvil - our setup :phone-android-app :van-app :phone-ios-umbrella /iosPhoneProject :demo-app /iosDemoProject
146. kotlin-inject-anvil - our setup :phone-android-app :van-app :phone-ios-umbrella /iosPhoneProject :demo-app /iosDemoProject All library modules
147. kotlin-inject-anvil - our setup :van-app AndroidAppComponent All library modules :demo-app androidMain/kotlin/AndroidAppComponent iosMain/kotlin/IosAppComponent desktopMain/kotlin/DesktopAppComponent :phone-ios-umbrella IosAppComponent /iosPhoneProject /iosDemoProject :phone-android-app AndroidAppComponent
148. :location kotlin-inject-anvil - our setup
149. :location kotlin-inject-anvil - our setup :public commonMain/kotlin/LocationProvider
150. :location kotlin-inject-anvil - our setup :public commonMain/kotlin/LocationProvider :impl commonMain/kotlin/RealTimeLocationProvider
151. :location kotlin-inject-anvil - our setup :public commonMain/kotlin/LocationProvider :impl commonMain/kotlin/RealTimeLocationProvider :weather :public commonMain/kotlin/WeatherRepository :impl commonMain/kotlin/WeatherRepositoryImpl
152. :location kotlin-inject-anvil - our setup :public commonMain/kotlin/LocationProvider :impl commonMain/kotlin/RealTimeLocationProvider :weather :public commonMain/kotlin/WeatherRepository :impl commonMain/kotlin/WeatherRepositoryImpl
153. :location kotlin-inject-anvil - our setup :public commonMain/kotlin/LocationProvider :impl androidMain/kotlin/AndroidLocationProvider iosMain /kotlin/IosLocationProvider :weather :public commonMain/kotlin/WeatherRepository :impl commonMain/kotlin/WeatherRepositoryImpl
154. kotlin-inject-anvil - our setup :location :public commonMain/kotlin/LocationProvider :impl androidMain/kotlin/AndroidLocationProvider iosMain /kotlin/IosLocationProvider :weather :public commonMain/kotlin/WeatherRepository :impl commonMain/kotlin/WeatherRepositoryImpl
155. kotlin-inject-anvil - our setup :location :public commonMain/kotlin/LocationProvider :impl-phone androidMain/kotlin/AndroidLocationProvider iosMain /kotlin/IosLocationProvider :impl-van androidMain/kotlin/VanLocationProvider :weather :public commonMain/kotlin/WeatherRepository :impl commonMain/kotlin/WeatherRepositoryImpl
156. kotlin-inject-anvil - our setup :location :public commonMain/kotlin/LocationProvider :impl-phone androidMain/kotlin/AndroidLocationProvider iosMain /kotlin/IosLocationProvider :impl-van androidMain/kotlin/VanLocationProvider :weather :public commonMain/kotlin/WeatherRepository :impl commonMain/kotlin/WeatherRepositoryImpl :van-app AndroidAppComponent :demo-app androidMain/kotlin/AndroidAppComponent iosMain/kotlin/IosAppComponent desktopMain/kotlin/DesktopAppComponent :phone-ios-umbrella IosAppComponent :phone-android-app AndroidAppComponent
157. kotlin-inject-anvil - our setup :location :public commonMain/kotlin/LocationProvider :impl-phone androidMain/kotlin/AndroidLocationProvider iosMain /kotlin/IosLocationProvider :impl-van androidMain/kotlin/VanLocationProvider :weather :public commonMain/kotlin/WeatherRepository :impl commonMain/kotlin/WeatherRepositoryImpl :van-app AndroidAppComponent :demo-app androidMain/kotlin/AndroidAppComponent iosMain/kotlin/IosAppComponent desktopMain/kotlin/DesktopAppComponent :phone-ios-umbrella IosAppComponent :phone-android-app AndroidAppComponent
158. kotlin-inject-anvil - our setup :location :public commonMain/kotlin/LocationProvider :impl-phone androidMain/kotlin/AndroidLocationProvider iosMain /kotlin/IosLocationProvider :impl-van androidMain/kotlin/VanLocationProvider :weather :public commonMain/kotlin/WeatherRepository :impl commonMain/kotlin/WeatherRepositoryImpl :van-app AndroidAppComponent :demo-app androidMain/kotlin/AndroidAppComponent iosMain/kotlin/IosAppComponent desktopMain/kotlin/DesktopAppComponent :phone-ios-umbrella IosAppComponent :phone-android-app AndroidAppComponent
159. kotlin-inject-anvil - our setup :location :public commonMain/kotlin/LocationProvider :impl-phone androidMain/kotlin/AndroidLocationProvider iosMain /kotlin/IosLocationProvider :impl-van androidMain/kotlin/VanLocationProvider :weather :public commonMain/kotlin/WeatherRepository :impl commonMain/kotlin/WeatherRepositoryImpl :van-app AndroidAppComponent :demo-app androidMain/kotlin/AndroidAppComponent iosMain/kotlin/IosAppComponent desktopMain/kotlin/DesktopAppComponent :phone-ios-umbrella IosAppComponent :phone-android-app AndroidAppComponent
160. kotlin-inject-anvil - our setup :location :public commonMain/kotlin/LocationProvider :impl-phone androidMain/kotlin/AndroidLocationProvider iosMain /kotlin/IosLocationProvider :impl-van androidMain/kotlin/VanLocationProvider :weather :public commonMain/kotlin/WeatherRepository :impl commonMain/kotlin/WeatherRepositoryImpl :van-app AndroidAppComponent :demo-app androidMain/kotlin/AndroidAppComponent iosMain/kotlin/IosAppComponent desktopMain/kotlin/DesktopAppComponent :phone-ios-umbrella IosAppComponent :phone-android-app AndroidAppComponent
161. kotlin-inject-anvil - Android instrumented tests :location :public commonMain/kotlin/LocationProvider :impl commonMain/kotlin/RealTimeLocationProvider :impl-robots commonMain/kotlin/FakeLocationProvider :demo-app androidMain/kotlin/AndroidAppComponent androidInstrumentedTest/kotlin/AndroidTestAppComponent
162. kotlin-inject-anvil - Android instrumented tests :location :public commonMain/kotlin/LocationProvider :impl commonMain/kotlin/RealTimeLocationProvider :impl-robots commonMain/kotlin/FakeLocationProvider :demo-app androidMain/kotlin/AndroidAppComponent androidInstrumentedTest/kotlin/AndroidTestAppComponent
163. kotlin-inject-anvil - Android instrumented tests :location :public commonMain/kotlin/LocationProvider :impl commonMain/kotlin/RealTimeLocationProvider :impl-robots commonMain/kotlin/FakeLocationProvider :demo-app androidMain/kotlin/AndroidAppComponent androidInstrumentedTest/kotlin/AndroidTestAppComponent
164. kotlin-inject-anvil - constructor injection // weather/impl/src/commonMain/kotlin @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class WeatherRepositoryImpl : WeatherRepository
165. kotlin-inject-anvil - constructor injection // weather/impl/src/commonMain/kotlin @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository // location/public/src/commonMain/kotlin interface LocationProvider
166. kotlin-inject-anvil - constructor injection // weather/impl/src/commonMain/kotlin @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class WeatherRepositoryImpl( val locationProvider: LocationProvider, ) : WeatherRepository // location/public/src/commonMain/kotlin interface LocationProvider // location/impl/src/commonMain/kotlin @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class RealTimeLocationProvider : LocationProvider
167. kotlin-inject-anvil - constructor injection interface NavigationManager { val screen: StateFlow<Screen> fun goTo(screen: Screen) } @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class NavigationManagerImpl : NavigationManager { private val _screen = MutableStateFlow(Screen.COUNTER) override val screen: StateFlow<Screen> = _screen override fun goTo(screen: Screen) { _screen.update { screen } } }
168. kotlin-inject-anvil - constructor injection interface CounterPresenter : MoleculePresenter<Unit, Model> @Inject @ContributesBinding(AppScope::class) class CounterPresenterImpl( private val counter: Counter, ) : CounterPresenter { @Composable override fun present(input: Unit): Model { ... } }
169. kotlin-inject-anvil - constructor injection @Inject class NavigationPresenter( private val navigationManager: NavigationManager, private val lazyCounterPresenter: () -> CounterPresenter, private val lazyItemPresenter: () -> ItemListDetailPresenter, ) : MoleculePresenter<Unit, Template> { @Composable override fun present(input: Unit): Template { ... } }
170. kotlin-inject-anvil - constructor injection @ContributesRenderer class ComposeCounterRenderer : ComposeRenderer<Model>() { @Composable override fun Compose(model: Model) { ... } }
171. kotlin-inject-anvil - constructor injection @ContributesRobot(AppScope::class) class ComposeCounterRobot : ComposeRobot() { fun seeCounterView() { ... } fun counterIsIncrementing() { ... } fun clickCounterText() { ... } }
172. kotlin-inject-anvil - retrieve objects class MainActivity : ComponentActivity() { private val rootScopeProvider get() = application as RootScopeProvider private val rendererFactoryRepository get() = rootScopeProvider.rootScope .diComponent<Component>() .rendererFactoryRepository private val navigationManager get() = rootScopeProvider.rootScope .diComponent<Component>() .navigationManager @ContributesTo(AppScope::class) interface Component { val rendererFactoryRepository: RendererFactoryRepository val navigationManager: NavigationManager } }
173. kotlin-inject-anvil - retrieve objects class MainActivity : ComponentActivity() { private val rootScopeProvider get() = application as RootScopeProvider private val rendererFactoryRepository get() = rootScopeProvider.rootScope .diComponent<Component>() .rendererFactoryRepository private val navigationManager get() = rootScopeProvider.rootScope .diComponent<Component>() .navigationManager @ContributesTo(AppScope::class) interface Component { val rendererFactoryRepository: RendererFactoryRepository val navigationManager: NavigationManager } }
174. kotlin-inject-anvil - retrieve objects class MainActivity : ComponentActivity() { private val rootScopeProvider get() = application as RootScopeProvider private val rendererFactoryRepository get() = rootScopeProvider.rootScope .diComponent<Component>() .rendererFactoryRepository private val navigationManager get() = rootScopeProvider.rootScope .diComponent<Component>() .navigationManager @ContributesTo(AppScope::class) interface Component { val rendererFactoryRepository: RendererFactoryRepository val navigationManager: NavigationManager } }
175. kotlin-inject-anvil - retrieve objects class MainActivity : ComponentActivity() { private val rootScopeProvider get() = application as RootScopeProvider private val rendererFactoryRepository get() = rootScopeProvider.rootScope .diComponent<Component>() .rendererFactoryRepository private val navigationManager get() = rootScopeProvider.rootScope .diComponent<Component>() .navigationManager @ContributesTo(AppScope::class) interface Component { val rendererFactoryRepository: RendererFactoryRepository val navigationManager: NavigationManager } }
176. kotlin-inject-anvil - provide Android dependencies // androidApp/src/androidMain/kotlin @SingleIn(AppScope::class) @MergeComponent(AppScope::class) abstract class AndroidAppComponent( @get:Provides val application: Application, )
177. kotlin-inject-anvil - provide Android dependencies // androidApp/src/androidMain/kotlin @SingleIn(AppScope::class) @MergeComponent(AppScope::class) abstract class AndroidAppComponent( @get:Provides val application: Application, ) // location/impl/src/androidMain/kotlin @ContributesTo(AppScope::class) interface LocationManagerComponent { @Provides fun provideLocationManager( application: Application ): LocationManager = checkNotNull(application.getSystemService<LocationManager>()) }
178. kotlin-inject-anvil - provide iOS dependencies // iosApp/src/iosMain/kotlin @SingleIn(AppScope::class) @MergeComponent(AppScope::class) abstract class IosAppComponent( @get:Provides val uiApplication: UIApplication, ) @MergeComponent.CreateComponent expect fun KClass<IosAppComponent>.createComponent(uiApplication: UIApplication): IosAppComponent
179. kotlin-inject-anvil - provide iOS dependencies // iosApp/src/iosMain/kotlin @SingleIn(AppScope::class) @MergeComponent(AppScope::class) abstract class IosAppComponent( @get:Provides val iosNativeImplementations: IosNativeImplementations, ) @MergeComponent.CreateComponent expect fun KClass<IosAppComponent>.createComponent(uiApplication: UIApplication): IosAppComponent interface IosNativeImplementations { val uiApplication: UIApplication @ContributesTo(AppScope::class) interface Component { @Provides fun provideUiApplication( iosNativeImplementations: IosNativeImplementations, ): UIApplication = iosNativeImplementations.uiApplication } }
180. kotlin-inject-anvil - provide iOS dependencies // iosApp/src/iosMain/kotlin @SingleIn(AppScope::class) @MergeComponent(AppScope::class) abstract class IosAppComponent( @get:Provides val iosNativeImplementations: IosNativeImplementations, ) @MergeComponent.CreateComponent expect fun KClass<IosAppComponent>.createComponent(uiApplication: UIApplication): IosAppComponent interface IosNativeImplementations { val uiApplication: UIApplication @ContributesTo(AppScope::class) interface Component { @Provides fun provideUiApplication( iosNativeImplementations: IosNativeImplementations, ): UIApplication = iosNativeImplementations.uiApplication } }
181. kotlin-inject-anvil - provide iOS dependencies // iosApp/src/iosMain/kotlin @SingleIn(AppScope::class) @MergeComponent(AppScope::class) abstract class IosAppComponent( @get:Provides val iosNativeImplementations: IosNativeImplementations, ) @MergeComponent.CreateComponent expect fun KClass<IosAppComponent>.createComponent(uiApplication: UIApplication): IosAppComponent interface IosNativeImplementations { val uiApplication: UIApplication @ContributesTo(AppScope::class) interface Component { @Provides fun provideUiApplication( iosNativeImplementations: IosNativeImplementations, ): UIApplication = iosNativeImplementations.uiApplication } }
182. kotlin-inject-anvil - extensions https://github.com/amzn/kotlin-inject-anvil?tab=readme-ov-file#custom-symbol-processors
183. kotlin-inject-anvil - extensions class ComposeCounterRenderer : ComposeRenderer<Model>() { }
184. kotlin-inject-anvil - extensions @Inject class ComposeCounterRenderer : ComposeRenderer<Model>() { @ContributesTo(RendererScope::class) interface Component { @Provides @IntoMap fun provideComposeCounterRenderer( renderer: () -> ComposeCounterRenderer, ): Pair<KClass<out BaseModel>, () -> Renderer<*>> = Model::class to renderer } }
185. kotlin-inject-anvil - extensions @ContributesRenderer class ComposeCounterRenderer : ComposeRenderer<Model>() { ... }
186. kotlin-inject-anvil - extensions class ComposeCounterRobot : ComposeRobot() { }
187. kotlin-inject-anvil - extensions @Inject class ComposeCounterRobot : ComposeRobot() { @ContributesTo(AppScope::class) interface Component { @Provides @IntoMap fun provideComposeCounterRobot( robot: () -> ComposeCounterRobot, ): Pair<KClass<out Robot>, () -> Robot> = ComposeCounterRobot::class to robot } }
188. kotlin-inject-anvil - extensions @ContributesRobot(AppScope::class) class ComposeCounterRobot : ComposeRobot() { ... }
189. kotlin-inject-anvil - extensions interface Scoped { fun onEnterScope(scope: Scope) = Unit fun onExitScope() = Unit }
190. kotlin-inject-anvil - extensions @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class CounterImpl : Counter, Scoped { private val _count = MutableStateFlow(0) override val count: StateFlow<Int> get() = _count override fun onEnterScope(scope: Scope) { scope.launch { while (isActive) { delay(500L) _count.update { it + 1 } } } } }
191. kotlin-inject-anvil - extensions @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class CounterImpl : Counter, Scoped { private val _count = MutableStateFlow(0) override val count: StateFlow<Int> get() = _count override fun onEnterScope(scope: Scope) { scope.launch { while (isActive) { delay(500L) _count.update { it + 1 } } } } }
192. kotlin-inject-anvil - expect-actual obsolete // Single :location module // location/src/commonMain/kotlin interface LocationProvider
193. kotlin-inject-anvil - expect-actual obsolete // Single :location module // location/src/commonMain/kotlin interface LocationProvider // location/src/commonMain/kotlin @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class NetworkLocationProvider : LocationProvider
194. kotlin-inject-anvil - expect-actual obsolete // Single :location module // location/src/commonMain/kotlin interface LocationProvider // location/src/commonMain/kotlin @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class NetworkLocationProvider : LocationProvider // location/src/androidMain/kotlin @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class, replaces = [NetworkLocationProvider::class]) class AndroidLocationProvider(application: Application) : LocationProvider
195. kotlin-inject-anvil - expect-actual obsolete // Single :location module // location/src/commonMain/kotlin interface LocationProvider // location/src/commonMain/kotlin @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class NetworkLocationProvider : LocationProvider // location/src/androidMain/kotlin @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class, replaces = [NetworkLocationProvider::class]) class AndroidLocationProvider(application: Application) : LocationProvider // location/src/iosMain/kotlin @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class, replaces = [NetworkLocationProvider::class]) class IosLocationProvider(application: UIApplication) : LocationProvider
196. kotlin-inject-anvil - common errors - duplicate binding > Task :sample:app:kspDebugKotlinAndroid FAILED e: [ksp] /app/build/generated/ksp/android/androidDebug/kotlin/amazon/lastmile/inject/SoftwareAmazonLastmileKotlin InjectAnvilSampleAndroidLocationProvider.kt:11: Cannot provide: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider e: [ksp] /app/build/generated/ksp/android/androidDebug/kotlin/amazon/lastmile/inject/SoftwareAmazonLastmileKotlin InjectAnvilSampleNetworkLocationProvider.kt:11: as it is already provided e: Error occurred in KSP, check log for detail
197. kotlin-inject-anvil - common errors - duplicate binding > Task :sample:app:kspDebugKotlinAndroid FAILED e: [ksp] /app/build/generated/ksp/android/androidDebug/kotlin/amazon/lastmile/inject/SoftwareAmazonLastmileKotlin InjectAnvilSampleAndroidLocationProvider.kt:11: Cannot provide: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider e: [ksp] /app/build/generated/ksp/android/androidDebug/kotlin/amazon/lastmile/inject/SoftwareAmazonLastmileKotlin InjectAnvilSampleNetworkLocationProvider.kt:11: as it is already provided e: Error occurred in KSP, check log for detail
198. kotlin-inject-anvil - common errors - duplicate binding > Task :sample:app:kspDebugKotlinAndroid FAILED e: [ksp] /app/build/generated/ksp/android/androidDebug/kotlin/amazon/lastmile/inject/SoftwareAmazonLastmileKotlin InjectAnvilSampleAndroidLocationProvider.kt:11: Cannot provide: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider e: [ksp] /app/build/generated/ksp/android/androidDebug/kotlin/amazon/lastmile/inject/SoftwareAmazonLastmileKotlin InjectAnvilSampleNetworkLocationProvider.kt:11: as it is already provided e: Error occurred in KSP, check log for detail
199. kotlin-inject-anvil - common errors - duplicate binding > Task :sample:app:kspDebugKotlinAndroid FAILED e: [ksp] /app/build/generated/ksp/android/androidDebug/kotlin/amazon/lastmile/inject/SoftwareAmazonLastmileKotlin InjectAnvilSampleAndroidLocationProvider.kt:11: Cannot provide: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider e: [ksp] /app/build/generated/ksp/android/androidDebug/kotlin/amazon/lastmile/inject/SoftwareAmazonLastmileKotlin InjectAnvilSampleNetworkLocationProvider.kt:11: as it is already provided e: Error occurred in KSP, check log for detail
200. kotlin-inject-anvil - common errors - missing binding > Task :sample:app:kspDebugKotlinAndroid FAILED e: [ksp] Cannot find an @Inject constructor or provider for: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider /app/src/androidMain/kotlin/software/amazon/lastmile/kotlin/inject/anvil/sample/AndroidAppComponent.kt:3 4: locationProvider: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider e: Error occurred in KSP, check log for detail
201. kotlin-inject-anvil - common errors - missing binding > Task :sample:app:kspDebugKotlinAndroid FAILED e: [ksp] Cannot find an @Inject constructor or provider for: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider /app/src/androidMain/kotlin/software/amazon/lastmile/kotlin/inject/anvil/sample/AndroidAppComponent.kt:3 4: locationProvider: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider e: Error occurred in KSP, check log for detail
202. kotlin-inject-anvil - common errors - missing binding > Task :sample:app:kspDebugKotlinAndroid FAILED e: [ksp] Cannot find an @Inject constructor or provider for: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider /app/src/androidMain/kotlin/software/amazon/lastmile/kotlin/inject/anvil/sample/AndroidAppComponent.kt:3 4: locationProvider: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider e: Error occurred in KSP, check log for detail
203. kotlin-inject-anvil - common errors - missing binding > Task :sample:app:kspDebugKotlinAndroid FAILED e: [ksp] Cannot find an @Inject constructor or provider for: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider /app/src/androidMain/kotlin/software/amazon/lastmile/kotlin/inject/anvil/sample/AndroidAppComponent.kt:3 4: locationProvider: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider e: Error occurred in KSP, check log for detail • No implementation exists • Missing @Inject • Missing @ContributesBinding • Missing Gradle dependency • Scope mismatch • Wrong qualifier
204. kotlin-inject-anvil - common errors - circular dependency @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class NetworkLocationProvider( weatherRepository: WeatherRepository ) : LocationProvider @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class WeatherRepositoryImpl( locationProvider: LocationProvider, ) : WeatherRepository
205. kotlin-inject-anvil - common errors - circular dependency > Task :sample:app:kspDebugKotlinAndroid FAILED e: [ksp] Cycle detected /app/src/androidMain/kotlin/software/amazon/lastmile/kotlin/inject/anvil/sample/AndroidAppComponent.kt:5 1: software.amazon.lastmile.kotlin.inject.anvil.sample.WeatherRepositoryImpl(locationProvider: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider) /app/build/generated/ksp/android/androidDebug/kotlin/amazon/lastmile/inject/SoftwareAmazonLastmileKotlin InjectAnvilSampleWeatherRepositoryImpl.kt:11: provideWeatherRepositoryImplWeatherRepository(weatherRepositoryImpl: software.amazon.lastmile.kotlin.inject.anvil.sample.WeatherRepositoryImpl): software.amazon.lastmile.kotlin.inject.anvil.sample.WeatherRepository /app/src/androidMain/kotlin/software/amazon/lastmile/kotlin/inject/anvil/sample/AndroidAppComponent.kt:4 2: software.amazon.lastmile.kotlin.inject.anvil.sample.NetworkLocationProvider(weatherRepository: software.amazon.lastmile.kotlin.inject.anvil.sample.WeatherRepository) /app/build/generated/ksp/android/androidDebug/kotlin/amazon/lastmile/inject/SoftwareAmazonLastmileKotlin InjectAnvilSampleNetworkLocationProvider.kt:11: provideNetworkLocationProviderLocationProvider(networkLocationProvider: software.amazon.lastmile.kotlin.inject.anvil.sample.NetworkLocationProvider): software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider /app/src/androidMain/kotlin/software/amazon/lastmile/kotlin/inject/anvil/sample/AndroidAppComponent.kt:3 4: locationProvider: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider e: Error occurred in KSP, check log for detail
206. kotlin-inject-anvil - common errors - circular dependency > Task :sample:app:kspDebugKotlinAndroid FAILED e: [ksp] Cycle detected /app/src/androidMain/kotlin/software/amazon/lastmile/kotlin/inject/anvil/sample/AndroidAppComponent.kt:5 1: software.amazon.lastmile.kotlin.inject.anvil.sample.WeatherRepositoryImpl(locationProvider: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider) /app/build/generated/ksp/android/androidDebug/kotlin/amazon/lastmile/inject/SoftwareAmazonLastmileKotlin InjectAnvilSampleWeatherRepositoryImpl.kt:11: provideWeatherRepositoryImplWeatherRepository(weatherRepositoryImpl: software.amazon.lastmile.kotlin.inject.anvil.sample.WeatherRepositoryImpl): software.amazon.lastmile.kotlin.inject.anvil.sample.WeatherRepository /app/src/androidMain/kotlin/software/amazon/lastmile/kotlin/inject/anvil/sample/AndroidAppComponent.kt:4 2: software.amazon.lastmile.kotlin.inject.anvil.sample.NetworkLocationProvider(weatherRepository: software.amazon.lastmile.kotlin.inject.anvil.sample.WeatherRepository) /app/build/generated/ksp/android/androidDebug/kotlin/amazon/lastmile/inject/SoftwareAmazonLastmileKotlin InjectAnvilSampleNetworkLocationProvider.kt:11: provideNetworkLocationProviderLocationProvider(networkLocationProvider: software.amazon.lastmile.kotlin.inject.anvil.sample.NetworkLocationProvider): software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider /app/src/androidMain/kotlin/software/amazon/lastmile/kotlin/inject/anvil/sample/AndroidAppComponent.kt:3 4: locationProvider: software.amazon.lastmile.kotlin.inject.anvil.sample.LocationProvider e: Error occurred in KSP, check log for detail
207. kotlin-inject-anvil - common errors - circular dependency @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class NetworkLocationProvider( weatherRepository: WeatherRepository ) : LocationProvider @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class WeatherRepositoryImpl( locationProvider: LocationProvider, ) : WeatherRepository
208. kotlin-inject-anvil - common errors - circular dependency @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class NetworkLocationProvider( weatherRepository: WeatherRepository ) : LocationProvider @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class WeatherRepositoryImpl( locationProvider: () -> LocationProvider, ) : WeatherRepository
209. kotlin-inject-anvil - common errors - circular dependency @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class NetworkLocationProvider( weatherRepository: WeatherRepository ) : LocationProvider @Inject @SingleIn(AppScope::class) @ContributesBinding(AppScope::class) class WeatherRepositoryImpl( locationProvider: () -> LocationProvider, ) : WeatherRepository
210. The next step
211. The next step https://zacsweers.github.io/metro
212. Summary • Dependency inversion and dependency injection help scale Kotlin Multiplatform applications • Manual dependency injection is possible, but requires a lot of maintenance • Compile time dependency injection framework are not magic • kotlin-inject-anvil is an efficient and flexible solution for Kotlin Multiplatform
213. Thank You, and Donʼt Forget to Vote ralf-wondratschek.com
214. Scale your Kotlin Multiplatform projects using dependency injection Ralf Wondratschek