Fails to parse empty sets or singleton sets

[dandroid126]

After writing an object with a Set of size of 0 or 1 to a json string, this json string cannot be parsed. An exception is thrown. This case works with Lists, but fails with Sets.

Here is an example test case:

fun main() {
    val listTest1 = ListTest(arrayListOf("a", "b", "c"))
    println(listTest1)
    val listJson1 = Klaxon().toJsonString(listTest1)
    println(listJson1)
    val listTest2 = Klaxon().parse<ListTest>(listJson1)
    println(listTest2)
    assert(listTest1 == listTest2)

    val listTest3 = ListTest(arrayListOf("a"))
    println(listTest3)
    val listJson2 = Klaxon().toJsonString(listTest3)
    println(listJson2)
    val listTest4 = Klaxon().parse<ListTest>(listJson2)
    println(listTest4)
    assert(listTest3 == listTest4)

    val setTest1 = SetTest(hashSetOf("a", "b", "c"))
    println(setTest1)
    val setJson1 = Klaxon().toJsonString(setTest1)
    println(setJson1)
    val setTest2 = Klaxon().parse<SetTest>(setJson1)
    println(setTest2)
    assert(setTest1 == setTest2)

    val setTest3 = SetTest(hashSetOf("a"))
    println(setTest3)
    val setJson2 = Klaxon().toJsonString(setTest3)
    println(setJson2)
    val setTest4 = Klaxon().parse<SetTest>(setJson2)
    println(setTest4)
    assert(setTest3 == setTest4)
}

data class SetTest(val set: HashSet<String>) {
    override fun equals(other: Any?): Boolean {
        return other is SetTest && set == other.set
    }
}
data class ListTest(val list: ArrayList<String>) {
    override fun equals(other: Any?): Boolean {
        return other is ListTest && list == other.list
    }
}

In this case, the exception thrown is Parameter set: expected kotlin.collections.HashSet<kotlin.String> /* = java.util.HashSet<kotlin.String> */ but received java.util.Collections$SingletonSet (value: [a])