I'm trying to get a long field to encode as a stri...

# serialization

[bartvh]

I'm trying to get a long field to encode as a string instead of as a number in JSON (for values that overflow double):

@Serializer(forClass = Long::class)
object LongStrSerializer : KSerializer<Long> {
    override fun deserialize(input: Decoder): Long =
            input.decodeString().toLong()

    override fun serialize(output: Encoder, obj: Long) =
            output.encodeString(obj.toString())
}

@kotlinx.serialization.Serializable
data class PlayerSummary(
        @kotlinx.serialization.Serializable(with = LongStrSerializer::class)
        val id: Long,
        val displayName: String
)

However this still results in:

{
  "displayName": "Jessie James",
  "id": 1337000000
}

What am I doing wrong?

[bartvh]

Inspecting the compiled code gives me

public void write$Self(@NotNull CompositeEncoder output, @NotNull SerialDescriptor serialDesc) {
      Intrinsics.checkParameterIsNotNull(output, "output");
      Intrinsics.checkParameterIsNotNull(serialDesc, "serialDesc");
      output.encodeLongElement(serialDesc, 0, this.id);
      output.encodeStringElement(serialDesc, 1, this.displayName);
   }

which is consistent with this result

[sandwwraith]

It is a known issue that properties with primitive types ignore serializers override (https://github.com/Kotlin/kotlinx.serialization/issues/252#issuecomment-440325053). It was fixed in the plugin and will be in the next release.