is it helpful in parsing data ?

Hey folks, hopefully quick question. I’ve been using Kotlinx serialization for a while and recently was trying to write a custom serializer/descriptor for a nested structure. I then realized that I wasn’t going to be able to reference the descriptor from within `buildClassSerialDescriptor`:

class SomeSerializer : KSerializer<SomeClass> {
    override val descriptor: SerialDescriptor = buildClassSerialDescriptor("SomeClass") {
        element<Boolean>("flag")
        element("nested", SomeSerializer().descriptor, isOptional = true)
    }
    // ...
}

This leads to a stack overflow since the

init

of

SomeSerializer

creates the

descriptor

which then tries to new up another

SomeSerializer

. That makes sense to me, but I wasn’t sure what the intended way of accomplishing something like this is. I know it’s possible if using one of the plugin generated serializers. Does this mean I might potentially need to implement

SerialDescriptor

myself or is this something that’s already solved for and I’m just not seeing the path forward?

Hey I can't figure out how to serilize this in kotlin. Preferably with kotlinx serilizastion. Here a typescript reference. Can someone guide me to an implementation?

function handleData(data: Record<string, unknown>) {
const bar: Record<string,unknown> = {
foo: "hi",
props: {...this.otherData, ...data}
}
return bar
}

This should end up as

{ 
foo: "hi",
props: {
  uno: 1
  dos: "two"
 }
}

Is there way to overrider json key that is responsible for the sealed class serialisation pick up?

Is there a way to provide a default type for a list of polymorphic types on the type declaration level (e.g. something akin to how

@JsonClassDiscriminator

makes class discriminators more customizable)? Sample code in thread.

(Edit: wrong channel, this is kotlinx.serialization not serialization in general. Apologies)

I have a sealed class hierarchy, but the input JSON (externally defined) uses

_type

instead of

type

as the discriminator. Doing

@SerialName("_type") val type: String

doesn't seem to work. A JSON content-based polymorphic deserialization seems like overkill for this. Is there some annotations that will work short of that?

Hey there, why don't custom serializers come have the Companion.serializer() method?? I have

@Serializable(with = SignedIn.Companion::class)
interface SignedIn : Session {

    @Serializer(forClass = SignedIn::class)
    companion object : KSerializer<SignedIn> {
        override val descriptor: SerialDescriptor = buildClassSerialDescriptor("session.signedin")

        override fun deserialize(decoder: Decoder): SignedIn {
            TODO("Not yet implemented")
        }

        override fun serialize(encoder: Encoder, value: SignedIn) {
            TODO()
        }
    }
}

And my test are as follows

val session : SignedIn = getSession()
println(Json.encodeToString(session)) // fails with: Serializer for class 'SignedIn' is not found.
println(Json.encodeToString(SignedIn,session)) // passes
println(Json.encodeToString(SignedIn.serializer(),session)) // won't compile

Why can't the compiler find the custom serializer??

Can I makes a field allowing either a string or an object of a certain class? The JSON is from others so I cannot change its shape.

I have made a KMP library and am trying to use the output aar in android and the following issue is coming

java.lang.RuntimeException: Unable to instantiate application com.rawat.address.AddressApp: java.lang.TypeNotPresentException: Type kotlinx.serialization.json.Json not present
        at android.app.LoadedApk.makeApplication(LoadedApk.java:1244)
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:6683)
        at android.app.ActivityThread.access$1300(ActivityThread.java:237)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1913)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
     Caused by: java.lang.TypeNotPresentException: Type kotlinx.serialization.json.Json not present
        at libcore.reflect.ParameterizedTypeImpl.getRawType(ParameterizedTypeImpl.java:69)
        at libcore.reflect.ParameterizedTypeImpl.getResolvedType(ParameterizedTypeImpl.java:77)
        at libcore.reflect.ListOfTypes.resolveTypes(ListOfTypes.java:70)
        at libcore.reflect.ListOfTypes.getResolvedTypes(ListOfTypes.java:55)
        at libcore.reflect.ParameterizedTypeImpl.getResolvedType(ParameterizedTypeImpl.java:76)
        at libcore.reflect.Types.getType(Types.java:56)
        at java.lang.Class.getGenericSuperclass(Class.java:878)
        at org.kodein.type.TypeReference.<init>(typeTokensJVM.kt:65)
        at com.library.address.di.KodeinKt$commonModule$$inlined$bindSingleton$default$1.<init>(typeTokensJVM.kt:83)
        at com.library.address.di.KodeinKt.commonModule(Kodein.kt:79)
        at com.library.address.di.KodeinKt.access$commonModule(Kodein.kt:1)
        at com.library.address.di.KodeinKt$initKodein$container$1.invoke(Kodein.kt:26)
        at com.library.address.di.KodeinKt$initKodein$container$1.invoke(Kodein.kt:23)
        at org.kodein.di.internal.DIImpl$Companion.newBuilder(DIImpl.kt:21)
        at org.kodein.di.internal.DIImpl$Companion.access$newBuilder(DIImpl.kt:20)
        at org.kodein.di.internal.DIImpl.<init>(DIImpl.kt:18)
        at org.kodein.di.DI$Companion.invoke(DI.kt:460)
        at org.kodein.di.DI$Companion.invoke$default(DI.kt:460)
        at com.library.address.di.KodeinKt.initKodein(Kodein.kt:23)
        at com.library.address.di.KodeinKt.initKodein$default(Kodein.kt:22)
        at com.rawat.address.AddressApp.<init>(AddressApp.kt:8)
        at java.lang.Class.newInstance(Native Method)
        at android.app.AppComponentFactory.instantiateApplication(AppComponentFactory.java:76)
        at androidx.core.app.CoreComponentFactory.instantiateApplication(CoreComponentFactory.java:52)
        at android.app.Instrumentation.newApplication(Instrumentation.java:1158)
        at android.app.LoadedApk.makeApplication(LoadedApk.java:1236)
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:6683) 
        at android.app.ActivityThread.access$1300(ActivityThread.java:237) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1913) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:223) 
        at android.app.ActivityThread.main(ActivityThread.java:7656) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) 
     Caused by: java.lang.ClassNotFoundException: kotlinx.serialization.json.Json
        at java.lang.Class.classForName(Native Method)
        at java.lang.Class.forName(Class.java:454)
        at libcore.reflect.ParameterizedTypeImpl.getRawType(ParameterizedTypeImpl.java:67)
        at libcore.reflect.ParameterizedTypeImpl.getResolvedType(ParameterizedTypeImpl.java:77) 
        at libcore.reflect.ListOfTypes.resolveTypes(ListOfTypes.java:70) 
        at libcore.reflect.ListOfTypes.getResolvedTypes(ListOfTypes.java:55) 
        at libcore.reflect.ParameterizedTypeImpl.getResolvedType(ParameterizedTypeImpl.java:76) 
        at libcore.reflect.Types.getType(Types.java:56) 
        at java.lang.Class.getGenericSuperclass(Class.java:878) 
        at org.kodein.type.TypeReference.<init>(typeTokensJVM.kt:65) 
        at com.library.address.di.KodeinKt$commonModule$$inlined$bindSingleton$default$1.<init>(typeTokensJVM.kt:83) 
        at com.library.address.di.KodeinKt.commonModule(Kodein.kt:79) 
        at com.library.address.di.KodeinKt.access$commonModule(Kodein.kt:1) 
        at com.library.address.di.KodeinKt$initKodein$container$1.invoke(Kodein.kt:26) 
        at com.library.address.di.KodeinKt$initKodein$container$1.invoke(Kodein.kt:23) 
        at org.kodein.di.internal.DIImpl$Companion.newBuilder(DIImpl.kt:21) 
        at org.kodein.di.internal.DIImpl$Companion.access$newBuilder(DIImpl.kt:20) 
        at org.kodein.di.internal.DIImpl.<init>(DIImpl.kt:18) 
        at org.kodein.di.DI$Companion.invoke(DI.kt:460) 
        at org.kodein.di.DI$Companion.invoke$default(DI.kt:460) 
        at com.library.address.di.KodeinKt.initKodein(Kodein.kt:23) 
        at com.library.address.di.KodeinKt.initKodein$default(Kodein.kt:22) 
        at com.rawat.address.AddressApp.<init>(AddressApp.kt:8) 
        at java.lang.Class.newInstance(Native Method) 
        at android.app.AppComponentFactory.instantiateApplication(AppComponentFactory.java:76) 
        at androidx.core.app.CoreComponentFactory.instantiateApplication(CoreComponentFactory.java:52) 
        at android.app.Instrumentation.newApplication(Instrumentation.java:1158) 
        at android.app.LoadedApk.makeApplication(LoadedApk.java:1236) 
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:6683) 
        at android.app.ActivityThread.access$1300(ActivityThread.java:237) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1913) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:223) 
        at android.app.ActivityThread.main(ActivityThread.java:7656) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) 
     Caused by: java.lang.ClassNotFoundException: Didn't find class "kotlinx.serialization.json.Json" on path: DexPathList[[dex file "/data/data/com.rawat.address/code_cache/.overlay/base.apk/classes7.dex", zip file "/data/app/~~U3m2k-_-ig7S7cGbCNubiA==/com.rawat.address-AHUnIhfVwegLlNWqeSa9yQ==/base.apk"],nativeLibraryDirectories=[/data/app/~~U3m2k-_-ig7S7cGbCNubiA==/com.rawat.address-AHUnIhfVwegLlNWqeSa9yQ==/lib/x86, /system/lib, /system_ext/lib]]
        at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:207)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
        at java.lang.Class.classForName(Native Method) 
        at java.lang.Class.forName(Class.java:454) 
        at libcore.reflect.ParameterizedTypeImpl.getRawType(ParameterizedTypeImpl.java:67) 
        at libcore.reflect.ParameterizedTypeImpl.getResolvedType(ParameterizedTypeImpl.java:77) 
        at libcore.reflect.ListOfTypes.resolveTypes(ListOfTypes.java:70) 
        at libcore.reflect.ListOfTypes.getResolvedTypes(ListOfTypes.java:55) 
        at libcore.reflect.ParameterizedTypeImpl.getResolvedType(ParameterizedTypeImpl.java:76) 
        at libcore.reflect.Types.getType(Types.java:56) 
        at java.lang.Class.getGenericSuperclass(Class.java:878) 
        at org.kodein.type.TypeReference.<init>(typeTokensJVM.kt:65) 
        at com.library.address.di.KodeinKt$commonModule$$inlined$bindSingleton$default$1.<init>(typeTokensJVM.kt:83) 
        at com.library.address.di.KodeinKt.commonModule(Kodein.kt:79) 
        at com.library.address.di.KodeinKt.access$commonModule(Kodein.kt:1) 
        at com.library.address.di.KodeinKt$initKodein$container$1.invoke(Kodein.kt:26) 
        at com.library.address.di.KodeinKt$initKodein$container$1.invoke(Kodein.kt:23) 
        at org.kodein.di.internal.DIImpl$Companion.newBuilder(DIImpl.kt:21) 
        at org.kodein.di.internal.DIImpl$Companion.access$newBuilder(DIImpl.kt:20) 
        at org.kodein.di.internal.DIImpl.<init>(DIImpl.kt:18) 
        at org.kodein.di.DI$Companion.invoke(DI.kt:460) 
        at org.kodein.di.DI$Companion.invoke$default(DI.kt:460) 
        at com.library.address.di.KodeinKt.initKodein(Kodein.kt:23) 
        at com.library.address.di.KodeinKt.initKodein$default(Kodein.kt:22) 
        at com.rawat.address.AddressApp.<init>(AddressApp.kt:8) 
        at java.lang.Class.newInstance(Native Method) 
        at android.app.AppComponentFactory.instantiateApplication(AppComponentFactory.java:76) 
        at androidx.core.app.CoreComponentFactory.instantiateApplication(CoreComponentFactory.java:52) 
        at android.app.Instrumentation.newApplication(Instrumentation.java:1158) 
        at android.app.LoadedApk.makeApplication(LoadedApk.java:1236) 
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:6683) 
        at android.app.ActivityThread.access$1300(ActivityThread.java:237) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1913) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:223) 
        at android.app.ActivityThread.main(ActivityThread.java:7656) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

Can anyone help?

Hey there, This might not be specific to serialization but I will ask here coz of obvious reasons. I am currently getting this error

> Task compileKotlinJs FAILED
e: Could not find "org.jetbrains.kotlinx:kotlinx-serialization-core" in [/home/andylamax/.local/share/kotlin/daemon]
e: java.lang.IllegalStateException: Could not find "org.jetbrains.kotlinx:kotlinx-serialization-core" in [/home/andylamax/.local/share/kotlin/daemon]

It should be known that this is a multiplatform project and task compileKotlinJvm completes successfully. Anyone experienced this?? how do I solve it?? Full error log in thread

Conceptual Question: I want to deserialize a JsonPrimitive (e.g. an integer) into specific class that is not an Integer because in the context of my code it is more than simply an Integer (e.g. a user ID that can be mapped to a User object using some DB). Is there some elegant way to do this with kotlinx.serialization? Because this requires more external information, this would probably need me to specify the mapping from

Integer -> User

when I instantiate the JSON deserializer. Is there such a functionality already available?

How can I achieve something like

@Serializable
@Contextual
abstract class BaseCreateProfileData {...}

i have a test in which i feed

"{"type": "A", ...}"

into a

PolymorphicType.A.serializer()

it fails with a

Unexpected JSON token at offset 11: Encountered an unknown key 'type'.

is there a way to skip that.. while also not adding

type

as a property to the class (because that creates other issue) or using

ignoreUnknownKeys = true

because there could be other.. issues ? oone way i found was to use

val a = Json.decodeFromString(PolymorphicType.serializer(), jsonString) as PolymorphicType.A

but that means that there is no way to use this.. except for encoding and decoding using the polymorphic types.. or you wil lose the

type

properties

Can I use

JsonTransformingSerializer

to remove discriminator?

Why does Kotlinx Serialization protobufs target proto 2, not proto 3?

Does anyone have a workaround to https://github.com/Kotlin/kotlinx.serialization/issues/944 ?

Is there any way to utilize classDiscriminator on a specific key when deserializing an abstract class, but without using the qualified name as a value, but a custom value?

Can anyone help me make sense of this serialization & javascript compiler error?

2022-01-25T21:03:42.507+0000 [DEBUG] [org.gradle.execution.plan.Node] Checking if all dependencies are complete for :jsProductionExecutableCompileSync
2022-01-25T21:03:42.507+0000 [DEBUG] [org.gradle.execution.plan.Node] All dependencies are complete for :jsProductionExecutableCompileSync
2022-01-25T21:03:42.507+0000 [DEBUG] [org.gradle.execution.plan.TaskNode] Checking if all must successors are complete for :jsProductionExecutableCompileSync
java.util.NoSuchElementException: Collection contains no element matching the predicate.
	at org.jetbrains.kotlinx.serialization.compiler.backend.ir.IrBuilderExtension$DefaultImpls.createLazyProperty(GeneratorHelpers.kt:1401)
	at org.jetbrains.kotlinx.serialization.compiler.backend.ir.SerializableCompanionIrGenerator.createLazyProperty(SerializableCompanionIrGenerator.kt:35)
	at org.jetbrains.kotlinx.serialization.compiler.backend.ir.SerializableCompanionIrGenerator.generateLazySerializerGetter(SerializableCompanionIrGenerator.kt:114)
	at org.jetbrains.kotlinx.serialization.compiler.backend.common.SerializableCompanionCodegen.generate(SerializableCompanionCodegen.kt:37)
	at org.jetbrains.kotlinx.serialization.compiler.backend.ir.SerializableCompanionIrGenerator$Companion.generate(SerializableCompanionIrGenerator.kt:50)
	at org.jetbrains.kotlinx.serialization.compiler.extensions.SerializerClassLowering.lower(SerializationLoweringExtension.kt:60)
...
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.compile(CompileServiceImpl.kt:1802)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at java.rmi/sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:359)
	at java.rmi/sun.rmi.transport.Transport$1.run(Transport.java:200)
	at java.rmi/sun.rmi.transport.Transport$1.run(Transport.java:197)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.rmi/sun.rmi.transport.Transport.serviceCall(Transport.java:196)
	at java.rmi/sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:562)
	at java.rmi/sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:796)
	at java.rmi/sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:677)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.rmi/sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:676)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)

I have code which runs and compiles fine on the JVM, but fails when compiling to Javascript. The error logs don't tell me where in my code it's failing. If it helps, my data model to be serialized has a

sealed

class with a number of children, each of which implement different interfaces. None of them use

by lazy

.

Hi! I Try to parse this class from json [1] ServerErrors is enum that should be deserialized well [2] I receive body [3] and try to parse it and get error [4] I can read and see what is wrote in, but i had this flag enabled in my json plugin in client [5] What can i miss?

Hi, any known workarounds for avoiding the type in json serialization?. For deserializing i can provide a selectDeserializer. Im found this https://github.com/Kotlin/kotlinx.serialization/issues/1247 but i think it does not mention any workaround for erasing the type in serialization. My use case is pretty simple i think, i just have a sealed interface with an implementation

Not sure if put this here or in Ktor I have a custom sealed class which works perfectly via local strings and ktor request if I use my custom serializer

@Serializable(with = CustomSealedClassSerializer::class)

. But I want to remove the dependency on

json

this sealed class in that Gradle module so I tried to use a

SerializerModule

Json {
    serializersModule = SerializersModule {
        contextual(CustomSealedClassSerializer::class) { args -> CustomSealedClassSerializer(args[0], args[1] }
    }
    ...
}

This is working perfectly with local strings, but with Ktor

2.0.0-alpha-1

and doing a request, it is not working, and debugging I am getting that

args

list is empty. Is there any workaround?

Hello! I’m trying to manually parse a

Map<String, String>

json response from github’s API into a

List<Object>

but I’m failing to do so, more in the thread

What does kotlin serialization do with

{"a": "a", "b":true, "c":1, "d": 10000000000000000000}

(if I want it as

Map<String, Any>

), and would it differentiate between

Int

Long

Float

and

Double

? Or does it just put all numbers in one of those (In Moshi, they just put them all in Doubles... https://github.com/square/moshi/issues/1144)? Do I need to manually serialize all this or is there an easy way to do this?

Hello, how can I configure the following:

sealed interface SystemXsId {
    @Serializable
    @JvmInline
    value class Known(val value: NonEmptyString) : SystemXsId

    @Serializable
    object Unknown : SystemXsId
}

to be serialized either as: • the value of NonEmptyString (which is already serializable and it works) - in case it is

Known

• null in case it is

Unknown

I probably have to specify an explicit serializer for the sealed interface, but how would it look like?

does kotlin serialziation uses

Serializable

of java ? why I am asking this question, actually we need to store the some serialized data in local/Room DB With Java's Serializable, problem is if we make any changes to the class implementing Serializable,. Its

serialVersionUID

gets changed, which causes the problem in deserializing

Hello, I'm working with a protocol that serializes fields as the indices of an array. For example

{
  "type": 1,
  "realm": "dev"
}

would actually be serialized as

[1, "dev"]

and I'm not too sure how to go about this. I was going to go with a message hierarchy and then delegate to the specific serializer based off the type, which I've successfully done before with the first JSON example. Though, I'm not sure how to do that with the second example, nor how to even (de)serialize the second example into a class that would look like this.

data class Foo(val type: Int, val realm: String)

It'd be nice to know if this is even possible, since I'm completely stumped on how to create a proper descriptor for the second situation. Thanks.

Hello 👋 Wondering if anyone tried using https://github.com/tschuchortdev/kotlin-compile-testing together with

kotlinx-serialization

? I'm trying to test out my auto-generated code but since serialization build plugin wasn't run, my compilation is failing as the serialization generated code is not available (e.g.

<foo>.serializer()

on serializable objects). Any ideas/suggestions?

Hi, is there a way to modify how an enum value will serialize ? I have this enum :

@Serializable
enum class Environment {
	BOTH,
	CLIENT,
	SERVER;
}

And I want the

BOTH

value to be serialized to

*