Using `DraftSource.build(actionId = 0, messageId =...

# serialization

[Davide Giuseppe Farella]

Using DraftSource.build(actionId = 0, messageId = "id") or also as DraftSource is failing with Can't locate argument-less serializer for class

[sandwwraith]

Try to pass serializer explicitly, e.g. PolymorphicSerializer(DraftSource::class) . Or try new library version with buillt-in support for sealed classes: https://github.com/Kotlin/kotlinx.serialization/blob/master/docs/polymorphism.md#sealed-classes (requires kotlin 1.3.60)

[Davide Giuseppe Farella]

Thank you, I’ve kinda solved because the class was a parameter for another class, so serializing it directly is working.


I was trying with DraftSource::class.serizalizer() 😄


Oh, good to know that sealed class are “automatically” supported now.
Some improvements has been applied?

I had to refactor in the following way for get it working:

sealed class DraftSource {
  ...
  open val messageId = generateDraftId()

👇

sealed class DraftSource {
  abstract val messageId: String

 @Serializable
  @Suppress("DataClassPrivateConstructor") // Still accessible by `copy` function
  data class Plain private constructor(
    override val actionId: Int,
    override val messageId: String
  ): DraftSource() {
    constructor(actionId: Int) :
            this(actionId, generateDraftId())
  }

[Davide Giuseppe Farella]

Otherwise messageId would generate a new id by generateDraftId() every time an object is deserialized