Is it possible to try deserializing String to one ...

# serialization

[starsep]

Is it possible to try deserializing String to one of types provided?
FooResponse is sealed class, I don't control response and therefore cannot add type discriminator as described in https://github.com/Kotlin/kotlinx.serialization/blob/master/docs/polymorphism.md#sealed-classes
At the moment I use this ugly code, is there a better way?

val jsonData = jsonSerializer.parseToJsonElement(responseData)

try {
    Json.decodeFromJsonElement<FooResponse.SuccessData>(jsonData)
} catch (e: SerializationException) {
    try {
        Json.decodeFromJsonElement<FooResponse.AnotherCase>(jsonData)
    } catch (e: SerializationException) {
        Json.decodeFromJsonElement<FooResponse.ErrorData>(jsonData)
    }
}

[diesieben07]

You could write your own KSerializer, which first deserializes to JsonElement, then checks the structure and based on the structure decides which class to decode into.

[sandwwraith]

JsonContentPolymorphicSerializer may help: https://github.com/Kotlin/kotlinx.serialization/blob/dev/docs/json.md#content-based-polymorphic-deserialization

[edenman]

i do something like this for handling protobuf oneof values: https://github.com/edenman/kmpPlayground/blob/edenman/kupdates/shared/src/commonMain/kotlin/chat/quill/data/OneOfSerializer.kt#L30