I am learning reflection, and encountered this pro...

# getting-started

[Xad Kile]

I am learning reflection, and encountered this problem. When class C is declared as below and performs some side effect on external variables. The external variables (q,__x,k,j) are counted as parameter to the primary constructors, and I can't invoke such constructor with only the 3 constructor arguments.

I want to map .parameters to dynamically create arguments to pass to this constructor, but in this case .parameter does not contain the correct number of parameter (which is 7), but only 3.

This does not happen if I move the variables out of the main function

Is this expected and how to deal with this?

fun main() {

    var q = false
    var __x = false
    var k = false
    var j = false

    data class C(val i: Int, val str: String, val b: Boolean) {
        init {
            q = true
            __x = true
            k = true
            j = false
        }
    }

    println(C::class.primaryConstructor?.call(1, "", true)) // this throws exception IllegalArgumentException: Callable expects 7 arguments, but 3 were provided
    println(C::class.primaryConstructor?.call(BooleanRef(),BooleanRef(),BooleanRef(),BooleanRef(),1, "", true)) // this works
    println(C::class.primaryConstructor?.parameters?.size) // this prints 3, not 7

}

[Sam]

I guess this is the same basic issue as https://youtrack.jetbrains.com/issue/KT-25573/

[Sam]

There seem to be several outstanding issues with reflection on local class and functions—that is, classes and functions that are declared inside another function. Probably best avoid those if you're just learning reflection.

[Xad Kile]

ok I see, so it is an outstanding issues, I'll keep that in mind, thank you 😄