Annotation type-safety

The library introduces a concept of annotation type-safety. Consider the following example:

@Rpc
interface MyService : RemoteService

class MyServiceImpl : MyService

fun <T : RemoteService> withService() {}

The compiler can't guarantee that the passed type parameter is the one for which the code generation was run:

withService<MyService>() // ok
withService<MyServiceImpl>() // compile time ok, runtime throws

The compiler plugin enforces annotation type-safety by requiring type parameters to have specific annotations, like @Rpc.

@Rpc
interface MyService : RemoteService

class MyServiceImpl : MyService

fun <@Rpc T : Any> withService() {}

withService<MyService>() // ok
withService<MyServiceImpl>() // compile time error

note

Annotation type safety only ensures that the resolved type parameters are annotated with the required annotation. The actual type of the passed argument may differ:

fun <@Rpc T : Any> registerService(body: () -> T) {}

// T is resolved to MyService,
// but 'body' returns MyServiceImpl
registerService<MyService> { ctx -> MyServiceImpl(ctx) }

// Error: T is resolved to MyServiceImpl
registerService { ctx -> MyServiceImpl(ctx) }

warning

This feature is highly experimental and may lead to unexpected behaviour. If you encounter any issues, please report them. To prevent critical bugs from affecting your app, you can disable this feature using the following configuration:

// build.gradle.kts
rpc {
    annotationTypeSafetyEnabled = false // true by default
}