@FilterNulls in Kotlin not excluding null in list

[elivity]

Hey,

I have the following issue and maybe I am just missing something:

I want to filter out null in an enum list. It works great in Java, but fails in Kotlin.

The following test reproduces the "wrong" behaviour:

import com.serjltt.moshi.adapters.DefaultOnDataMismatchAdapter
import com.serjltt.moshi.adapters.FilterNulls
import com.squareup.moshi.Moshi
import org.junit.Test

class AnimalTest {
    enum class Animal {
        Dog,
        Cat
    }

    data class Animals(
        @FilterNulls val animals: List<Animal> = arrayListOf()
    )

    @Test
    fun testMoshiEnumNullable() {
        val moshi = Moshi.Builder()
            .add(FilterNulls.ADAPTER_FACTORY)
            .add(DefaultOnDataMismatchAdapter.newFactory(Animal::class.java, null))
            .add(com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory())
            .build()

        val response = moshi.adapter(Animals::class.java).fromJson("""{"animals" : [
            "Dog",
            "Unknown"
        ]}""")

        assert(response != null)
        // Gets [Dog, null] instead of just [Dog]
        assert(response == Animals(animals = arrayListOf(Animal.Dog)))
    }
}