Kotlinx Serializer for List<T> instead of just T at Serializable annotation of field

Question

So I have this class to for Json deserialization:

@Serializable
data class NetworkUser(
    @SerialName("id")
    val id: Long,

    ...

    @Serializable(RoleSerializer::class)
    @SerialName("role")
    val role: List<Role>
)

Serializer for Role Enum class:

object RoleSerializer : KSerializer<Role> {
    override fun deserialize(decoder: Decoder): Role =
        Role.valueOf(decoder.decodeString())

    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor(
        serialName = "Instant",
        kind = PrimitiveKind.STRING,
    )

    override fun serialize(encoder: Encoder, value: Role) =
        encoder.encodeString(value.name)
}

But I get this error

How can I use it with List<Role> instead of just Role? I don't really want to create another KSerializer just for parsing a list, it is boilerplate code

In my case I need it for Android Retrofit Json parsing, if I need to create two KSerializer for object and list of objects then I better return back Gson serialization and TypeAdapters, you only create a Type Adapter for object once with Gson, no need to create it for lists, also you don't need to add annotation to every field where it's used

Answer 1

Maybe try:

@SerialName("role") val role: List<@Serializable(with = RoleSerializer::class) Role>