support declare a component definition with primary type

[xudshen]

Problem

When we want to declare an instance on the fly, the current logic uses the instance's class type as primary type for the bean definition.
But there are sometimes that we might expect using instance's supertype as primary type.

open class Lifecycle
class UserLifecycle1 : Lifecycle()
class UserLifecycle2 : Lifecycle()

val koin = koinApplication {
    printLogger()
    modules(module {
        scope(named("UserSession1")) {
            scoped(named("lifecycle")) { UserLifecycle1() as Lifecycle }
        }
        scope(named("UserSession2")) {
        }
    })
}.koin

val session1 = koin.createScope("session1", named("UserSession1"))
val session2 = koin.createScope("session2", named("UserSession2"))
session2.declare(UserLifecycle2() as Lifecycle, qualifier = named("lifecycle"))

session1.get<Lifecycle>(named("lifecycle")) // return UserLifecycle1 instance
session2.get<UserLifecycle2>(named("lifecycle")) // return UserLifecycle2 instance
session2.get<Lifecycle>(named("lifecycle")) // throw definition not found

scoped(named("lifecycle")) { UserLifecycle1() as Lifecycle } and session2.declare(UserLifecycle2() as Lifecycle, qualifier = named("lifecycle")) should achieve the same effect intuitively.

Solution

I've changed the Scope#declare function and added a clazz parameter to specify the primary type for current definition. Inside ScopeDefinition#saveNewDefinition, it will check if clazz is same as or supertype of provided instance.

// session2.declare(UserLifecycle2() as Lifecycle, qualifier = named("lifecycle"))
session2.declare(UserLifecycle2(), Lifecycle::class, qualifier = named("lifecycle"))

session2.get<Lifecycle>(named("lifecycle")) // return UserLifecycle2 instance as expected

[arnaudgiuliani]

not sure this is the right approach. Can you try to use reified types at Scope API level

[xudshen]

hello, I've changed the approach with reified type parameters. The only downside is making the Definitions#createSingle public.