Is it possible to create an interface which requires one of its properties to be

@Serializable

? Or

@Contextual

? Ideally it would be a compile-time exception if the contract wasn't followed, but not the end of the world if its a runtime problem.

I'm trying to find a way to make a case-insensitive deserialization, is it possible? I didn't manage to find anything in the documention about json configuration.

Hi, is there a way to completely deactivate polymorphic serialization and just say to the library to serialize whatever there is inside because I don't need any deserialization later ?

Anyone aware of way to create custom deserialization of some "map type" json in to a list (more in thread)....

Hello, why do you think kotlinx.serialization protobuf is still experimental? Can we expect major breaking changes in the not too distant future?

I'm trying to compile with generic classes like in the documentation, but I can't seem to get it to work. https://github.com/Kotlin/kotlinx.serialization/blob/master/docs/basic-serialization.md#generic-classes

I feel like I'm missing something obvious when trying to deserialise some JSON into an enum. Due to some developers not reading the spec properly, the server returns some JSON that is keyed incorrecty, and is lowercase.

{
  "healthCheck": "success"
}

I need to parse it into an object of

HealthCheck

@Serializable
data class HealthCheck(
  @SerialName("healthCheck")
  @Serializable(with = StatusSerializer::class)
  val result: Status
) {
  @Serializable
  enum class Status {
    SUCCESS
  }
}

object StatusSerializer : JsonTransformingSerializer<HealthCheck.Status>(HealthCheck.Status.serializer()) {
  override fun transformDeserialize(element: JsonElement): JsonElement {
    val el = super.transformDeserialize(element)

    return JsonPrimitive(el.toString().uppercase())
  }
}

However I get an exception

HealthCheck.Status does not contain element with name '"SUCCESS"'

Is there any code generation from XSD schema available?

I'm trying to make an Event publisher that can take any serializable type as a payload and send it off to the event endpoint that we have, but I'm not sure how to do that without the failure

java.lang.IndexOutOfBoundsException: Index 0 out of bounds for length 0

. Here is my attached code, but essentially I want a single function that can publish all my events and every time I want to create a new type of event, I can just create a class that extends it with the right payload type.

I have a class that sometimes I need to merge into another class when serializing. Is it possible to add a descriptor to another descriptor? Essentially merging the elements together?

is there some way to require that a type is serializable, something like

class Container<@Serializable T> …

?

Hey guys, is the plugin code open-sourced?

Hello 👋 Is there a way to coerce default polymorphic type programmatically? i.e. something like https://github.com/Kotlin/kotlinx.serialization/blob/master/docs/polymorphism.md#default-polymorphic-type-handler-for-deserialization but by using only annotations Guess I can provide default value together with

Json {
    coerceInputValues = true
}

Is it expected that the first deserialization from a

Json

instance will be slow? Parsing a small JSON text in some unit tests. The first test takes 167 ms (longer on build machine) just in the parsing. All the other tests take about one millisecond to parse the same amount of JSON. This is on the JVM with Kotlin 1.6.10 and Serialization 1.3.2.

I have a KMM library that use kotlinx.serialization for serialization. Some Android application has a dependency to my library and it has an issue with proguard. This app has

minifyEnabled = true

and therefore some of my data classes are removed by proguard. I was able to resolve that by adding a proguard rule to keep this classes, but it did work only when I apply this rule on the app side. Wonder if it is even possible to have this rules on the library side so that app would not need to modify their proguard rules

Hi folks, there is any annotation that can be used to tell that a type must be a

@Serializable

one? For Java we can easily use Serializable and on Android also Parcelable.

Hi 👋 Background: I've got a service, let's call it Service 1, that offers a RESTful API endpoint and uses Jackson for deserialization. Service 1 makes API calls to Service 2. To make these calls, Service 1 uses a Service 2 client SDK which is written in Kotlin, defines Kotlin DTOs, and uses Kotlin Serialization. The SDK isn't just written in Kotlin, it's actually auto-generated from an OpenAPI spec, so I can't easily change the SDK's code. Question: Some of the data Service 1 receives has to be passed verbatim to Service 2. I'm trying to avoid rewriting DTOs for all this data, since they're sitting right there in the SDK with Kotlin Serialization annotations. Is there some way for Service 1 to use Jackson to deserialize into those Kotin Serialization DTOs, e.g. treating

@SerialName

as

@JsonProperty

for these simple DTOs.

Hi, I'm getting this error when I run some Kotlin code on Elastic Beanstalk that I'm not getting when I run locally, it appears to be an exception within

KClasses.getMemberProperties()

. I'm using Kotlin 1.6.10 - would appreciate any suggestions:

java.lang.ClassCastException: class kotlin.jvm.internal.ClassReference cannot be cast to class kotlin.reflect.jvm.internal.KClassImpl (kotlin.jvm.internal.ClassReference and kotlin.reflect.jvm.internal.KClassImpl are in unnamed module of loader 'app')
 at kotlin.reflect.full.KClasses.getMemberProperties(KClasses.kt:148)

Hi folks, when i serialize manually in json the outcome produces escaped chars:

"data": "{\"imahubKey\":\"eyJhbGciOiJIUzUxMiJ9.eyJpc3MiOiJpbWFodWIiLCJzdWIiOiJ0ZXN0NTIxMDEiLCJleHAiOjE2NDY4MzM2MzIsImlhdCI6MTY0NjgyMzYzMn0.5L6T1-8EkzR41IX2V43ImI1hfBrIMEJEXXTr88FD8QbST82-l4_kg31tjA0xph_LgvUGPuMtXsRhfx44WgvcAA\"}"

This is my serializer:

public fun SharedPayload.encodeToJson(): JsonElement = SharedPayloadJson.encodeToJsonElement(
    SharedSharedPayloadFromBuilder.serializer(), this as SharedSharedPayloadFromBuilder

How can i disable the escaping when im dealing with strings?

Hi folks, i have an interface

public sealed interface SharedPayload {
    public val data: JsonElement?
    public val error: ApiError?
}

and an impl

@PublishedApi
@Serializable
internal class SharedSharedPayloadFromBuilder : SharedPayloadBuilder, SharedPayload {
    @Transient
    private var hasData = false

    @Transient
    private var hasErrors = false

    @Polymorphic
    override var data: JsonElement? = null
        private set

    override var error: ApiError? = null
        private set

    override fun data(value: JsonElement?) {
        if (hasData) {
            error("Data already provided")
        }
        data = value
        hasData = true
    }

    override fun error(value: ApiError) {
        if (hasErrors) {
            error("Error already provided")
        }
        error = value
        hasErrors = true
    }

    fun build(): SharedPayload {
        check(hasData || hasErrors) { "Data or error is required" }
        return this
    }
}

Im serializing any object into data as jsonElement, then i want to serialize the whole object as a jsonElement, yet i got this err

Serializer for JsonPrimitive of kind STRING cannot be serialized polymorphically with class discriminator.

Anyone got any idea what im doing wrong? The test i run is this:

@Test
fun test() {
    val payload = buildSharedPayload {
        data(ApiRequest("Hello from api request as json element"))
    }
    println(payload.data)
    val jsonElement = payload.encodeToJson()
    println(jsonElement)

    val data = SharedPayload("Hello im json element")//.encodeToJson()
    println(data.data)
}

fyi here is a sample project with this: https://github.com/GeorgePap-719/simple-springboot-kotlinx-serialization Thanks in advance for any help!

Hi! I get this error when trying to do a polymorphic deserialization of a class with generic typing. I am using a custom serializer

KSerializer

to handle the different subclasses. Code in thread.

java.lang.AssertionError: No such value argument slot in IrConstructorCallImpl: 0 (total=0).
Symbol: /IntValueProviderSerializer.<init>|-5645683436151566731[0]

We are using a multiplatform project with

org.jetbrains.kotlinx:kotlinx-serialization-json: 1.3.2

i need to decode a json string with a weird quirk. lists with only 1 entry omit the

[]

as if it was just a simple property of the inner type. eg

x = listOf("foo", "bar")

is serialized as

"x": ["foo", "bar"]

(as expected), but

x = listOf("foo")

is serialized as

"x": "foo"

instead of

"x": ["foo"]

. this breaks the parser, because it sees a

x: String

property where

x: List<String>

is expected. how do i work around this?

hello there, is there a way to serialize this without using a custom serializer?

@Serializable
sealed class InfoResults<out T> {
    @Serializable
    data class Shared<out T>(val data: T) : InfoResults<T>()

    @Serializable
    data class NotShared(val message: String) : InfoResults<Nothing>()
}

hi, I'm working on creating a library to generate TypeScript interfaces based on SerialDescriptors. I'm stuck on how to translate parent and sub classes though. Is it possible to get this information from SerialDescriptors, or SerializersModule? Or do I have to use kapt, or reflection, or KSP? Attached is an example of what I'd like to make

Hello World, I have litteraly dozens of Enum classes like this where the default Enum serializer don't work only because the case is different, PascalCase in Kotlin versus snake_case when serialized. Is it possible to somehow wrap the default serializer to add a call to

.toPascalCase()

and

.to_snake_case()

instead of having all those

@SerialName

?

Hello, I'm getting error

Unexpected JSON token at offset 11023: Expected start of the object '{', but had ':' instead

JSON input: .....","type":"BLOGPOST","category":"e054042e-bc50-4743-a6f5-94d9.....

and I'm not sure why

how do I implement kotlinx.serialization in spring data redis?

How can I specify a class discriminator on an interface?

@JsonClassDiscriminator("country")
sealed interface Market {

    @Serializable @SerialName("UK")
    object UnitedKingdom : Market

    @Serializable @SerialName("US")
    enum class UnitedStates : Market {
        @SerialName("TX") Texas,
    }
}

Here the discriminator doesn’t do anything because the interface isn’t serializable (I think). I don’t want to globally specify the discriminator because it’s only applicable to this hierarchy

Hi folks, there is any solution for better error handling when using Kotlinx.serialization and Json? Currently the SerializationException don't tell much, would be awesome to see what names/types fail in the serialization.