[kotlin][client] add support for unknown default case with Kotlinx Serialization (#12930)

* [kotlin][client] Kotlinx Serialization cleanup

* [kotlin][client] Kotlinx Serialization cleanup

* [kotlin][client] add support for unknown default case with Kotlinx Serialization

* [kotlin][client] add support for unknown default case with Kotlinx Serialization

* [kotlin][client] add support for unknown default case with Kotlinx Serialization

* [kotlin][client] improve Kotlinx Serialization naming

* [kotlin][client] improve Kotlinx Serialization naming

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt

@@ -26,7 +26,8 @@ import okhttp3.OkHttpClient
 import org.openapitools.client.models.ModelApiResponse
 import org.openapitools.client.models.Pet
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
 
 import org.openapitools.client.infrastructure.ApiClient
 import org.openapitools.client.infrastructure.ApiResponse

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt

@@ -25,7 +25,8 @@ import okhttp3.OkHttpClient
 
 import org.openapitools.client.models.Order
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
 
 import org.openapitools.client.infrastructure.ApiClient
 import org.openapitools.client.infrastructure.ApiResponse

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt

@@ -25,7 +25,8 @@ import okhttp3.OkHttpClient
 
 import org.openapitools.client.models.User
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
 
 import org.openapitools.client.infrastructure.ApiClient
 import org.openapitools.client.infrastructure.ApiResponse

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -28,7 +28,8 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
-import com.squareup.moshi.adapter
+import kotlinx.serialization.decodeFromString
+import kotlinx.serialization.encodeToString
 
 open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClient) {
     companion object {
@@ -105,7 +106,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                 if (content == null) {
                     EMPTY_REQUEST
                 } else {
-                    Serializer.moshi.adapter(T::class.java).toJson(content)
+                    Serializer.kotlinxSerializationJson.encodeToString(content)
                         .toRequestBody((mediaType ?: JsonMediaType).toMediaTypeOrNull())
                 }
             mediaType == XmlMediaType -> throw UnsupportedOperationException("xml not currently supported.")
@@ -113,7 +114,6 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             else -> throw UnsupportedOperationException("requestBody currently only supports JSON body and File body.")
         }
 
-    @OptIn(ExperimentalStdlibApi::class)
     protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
         if(body == null) {
             return null
@@ -140,7 +140,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
         return when {
             mediaType==null || (mediaType.startsWith("application/") && mediaType.endsWith("json")) ->
-                Serializer.moshi.adapter<T>().fromJson(bodyContent)
+                Serializer.kotlinxSerializationJson.decodeFromString<T>(bodyContent)
             else ->  throw UnsupportedOperationException("responseBody currently only supports JSON body.")
         }
     }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/AtomicBooleanAdapter.kt

@@ -0,0 +1,21 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+import java.util.concurrent.atomic.AtomicBoolean
+
+@Serializer(forClass = AtomicBoolean::class)
+object AtomicBooleanAdapter : KSerializer<AtomicBoolean> {
+    override fun serialize(encoder: Encoder, value: AtomicBoolean) {
+        encoder.encodeBoolean(value.get())
+    }
+
+    override fun deserialize(decoder: Decoder): AtomicBoolean = AtomicBoolean(decoder.decodeBoolean())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("AtomicBoolean", PrimitiveKind.BOOLEAN)
+}

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/AtomicIntegerAdapter.kt

@@ -0,0 +1,21 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+import java.util.concurrent.atomic.AtomicInteger
+
+@Serializer(forClass = AtomicInteger::class)
+object AtomicIntegerAdapter : KSerializer<AtomicInteger> {
+    override fun serialize(encoder: Encoder, value: AtomicInteger) {
+        encoder.encodeInt(value.get())
+    }
+
+    override fun deserialize(decoder: Decoder): AtomicInteger = AtomicInteger(decoder.decodeInt())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("AtomicInteger", PrimitiveKind.INT)
+}

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/AtomicLongAdapter.kt

@@ -0,0 +1,21 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+import java.util.concurrent.atomic.AtomicLong
+
+@Serializer(forClass = AtomicLong::class)
+object AtomicLongAdapter : KSerializer<AtomicLong> {
+    override fun serialize(encoder: Encoder, value: AtomicLong) {
+        encoder.encodeLong(value.get())
+    }
+
+    override fun deserialize(decoder: Decoder): AtomicLong = AtomicLong(decoder.decodeLong())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("AtomicLong", PrimitiveKind.LONG)
+}

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/BigDecimalAdapter.kt

@@ -1,17 +1,17 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.math.BigDecimal
 
-class BigDecimalAdapter {
-    @ToJson
-    fun toJson(value: BigDecimal): String {
-        return value.toPlainString()
-    }
-
-    @FromJson
-    fun fromJson(value: String): BigDecimal {
-        return BigDecimal(value)
-    }
+@Serializer(forClass = BigDecimal::class)
+object BigDecimalAdapter : KSerializer<BigDecimal> {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("BigDecimal", PrimitiveKind.STRING)
+    override fun deserialize(decoder: Decoder): BigDecimal = BigDecimal(decoder.decodeString())
+    override fun serialize(encoder: Encoder, value: BigDecimal) = encoder.encodeString(value.toPlainString())
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/BigIntegerAdapter.kt

@@ -1,17 +1,22 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.math.BigInteger
 
-class BigIntegerAdapter {
-    @ToJson
-    fun toJson(value: BigInteger): String {
-        return value.toString()
+@Serializer(forClass = BigInteger::class)
+object BigIntegerAdapter : KSerializer<BigInteger> {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("BigInteger", PrimitiveKind.STRING)
+    override fun deserialize(decoder: Decoder): BigInteger {
+        return BigInteger(decoder.decodeString())
     }
 
-    @FromJson
-    fun fromJson(value: String): BigInteger {
-        return BigInteger(value)
+    override fun serialize(encoder: Encoder, value: BigInteger) {
+        encoder.encodeString(value.toString())
     }
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ByteArrayAdapter.kt

@@ -1,12 +0,0 @@
-package org.openapitools.client.infrastructure
-
-import com.squareup.moshi.FromJson
-import com.squareup.moshi.ToJson
-
-class ByteArrayAdapter {
-    @ToJson
-    fun toJson(data: ByteArray): String = String(data)
-
-    @FromJson
-    fun fromJson(data: String): ByteArray = data.toByteArray()
-}

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/LocalDateAdapter.kt

@@ -1,19 +1,24 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.time.LocalDate
 import java.time.format.DateTimeFormatter
 
-class LocalDateAdapter {
-    @ToJson
-    fun toJson(value: LocalDate): String {
-        return DateTimeFormatter.ISO_LOCAL_DATE.format(value)
+@Serializer(forClass = LocalDate::class)
+object LocalDateAdapter : KSerializer<LocalDate> {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("LocalDate", PrimitiveKind.STRING)
+
+    override fun serialize(encoder: Encoder, value: LocalDate) {
+        encoder.encodeString(DateTimeFormatter.ISO_LOCAL_DATE.format(value))
     }
 
-    @FromJson
-    fun fromJson(value: String): LocalDate {
-        return LocalDate.parse(value, DateTimeFormatter.ISO_LOCAL_DATE)
+    override fun deserialize(decoder: Decoder): LocalDate {
+        return LocalDate.parse(decoder.decodeString(), DateTimeFormatter.ISO_LOCAL_DATE)
     }
-
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/LocalDateTimeAdapter.kt

@@ -1,19 +1,24 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.time.LocalDateTime
 import java.time.format.DateTimeFormatter
 
-class LocalDateTimeAdapter {
-    @ToJson
-    fun toJson(value: LocalDateTime): String {
-        return DateTimeFormatter.ISO_LOCAL_DATE_TIME.format(value)
+@Serializer(forClass = LocalDateTime::class)
+object LocalDateTimeAdapter : KSerializer<LocalDateTime> {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("LocalDateTime", PrimitiveKind.STRING)
+
+    override fun serialize(encoder: Encoder, value: LocalDateTime) {
+        encoder.encodeString(DateTimeFormatter.ISO_LOCAL_DATE_TIME.format(value))
     }
 
-    @FromJson
-    fun fromJson(value: String): LocalDateTime {
-        return LocalDateTime.parse(value, DateTimeFormatter.ISO_LOCAL_DATE_TIME)
+    override fun deserialize(decoder: Decoder): LocalDateTime {
+        return LocalDateTime.parse(decoder.decodeString(), DateTimeFormatter.ISO_LOCAL_DATE_TIME)
     }
-
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/OffsetDateTimeAdapter.kt

@@ -1,19 +1,24 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.time.OffsetDateTime
 import java.time.format.DateTimeFormatter
 
-class OffsetDateTimeAdapter {
-    @ToJson
-    fun toJson(value: OffsetDateTime): String {
-        return DateTimeFormatter.ISO_OFFSET_DATE_TIME.format(value)
+@Serializer(forClass = OffsetDateTime::class)
+object OffsetDateTimeAdapter : KSerializer<OffsetDateTime> {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("OffsetDateTime", PrimitiveKind.STRING)
+
+    override fun serialize(encoder: Encoder, value: OffsetDateTime) {
+        encoder.encodeString(DateTimeFormatter.ISO_OFFSET_DATE_TIME.format(value))
     }
 
-    @FromJson
-    fun fromJson(value: String): OffsetDateTime {
-        return OffsetDateTime.parse(value, DateTimeFormatter.ISO_OFFSET_DATE_TIME)
+    override fun deserialize(decoder: Decoder): OffsetDateTime {
+        return OffsetDateTime.parse(decoder.decodeString(), DateTimeFormatter.ISO_OFFSET_DATE_TIME)
     }
-
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt

@@ -1,23 +1,52 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.Moshi
-import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
+import java.math.BigDecimal
+import java.math.BigInteger
+import java.time.LocalDate
+import java.time.LocalDateTime
+import java.time.OffsetDateTime
+import java.util.UUID
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.modules.SerializersModule
+import java.net.URI
+import java.net.URL
+import java.util.concurrent.atomic.AtomicBoolean
+import java.util.concurrent.atomic.AtomicInteger
+import java.util.concurrent.atomic.AtomicLong
 
 object Serializer {
+    @Deprecated("Use Serializer.kotlinxSerializationAdapters instead", replaceWith = ReplaceWith("Serializer.kotlinxSerializationAdapters"))
     @JvmStatic
-    val moshiBuilder: Moshi.Builder = Moshi.Builder()
-        .add(OffsetDateTimeAdapter())
-        .add(LocalDateTimeAdapter())
-        .add(LocalDateAdapter())
-        .add(UUIDAdapter())
-        .add(ByteArrayAdapter())
-        .add(URIAdapter())
-        .add(KotlinJsonAdapterFactory())
-        .add(BigDecimalAdapter())
-        .add(BigIntegerAdapter())
+    val kotlinSerializationAdapters: SerializersModule
+        get() { return kotlinxSerializationAdapters }
 
     @JvmStatic
-    val moshi: Moshi by lazy {
-        moshiBuilder.build()
+    val kotlinxSerializationAdapters = SerializersModule {
+        contextual(BigDecimal::class, BigDecimalAdapter)
+        contextual(BigInteger::class, BigIntegerAdapter)
+        contextual(LocalDate::class, LocalDateAdapter)
+        contextual(LocalDateTime::class, LocalDateTimeAdapter)
+        contextual(OffsetDateTime::class, OffsetDateTimeAdapter)
+        contextual(UUID::class, UUIDAdapter)
+        contextual(AtomicInteger::class, AtomicIntegerAdapter)
+        contextual(AtomicLong::class, AtomicLongAdapter)
+        contextual(AtomicBoolean::class, AtomicBooleanAdapter)
+        contextual(URI::class, URIAdapter)
+        contextual(URL::class, URLAdapter)
+        contextual(StringBuilder::class, StringBuilderAdapter)
+    }
+
+    @Deprecated("Use Serializer.kotlinxSerializationJson instead", replaceWith = ReplaceWith("Serializer.kotlinxSerializationJson"))
+    @JvmStatic
+    val jvmJson: Json
+        get() { return kotlinxSerializationJson }
+
+    @JvmStatic
+    val kotlinxSerializationJson: Json by lazy {
+        Json {
+            serializersModule = kotlinxSerializationAdapters
+            ignoreUnknownKeys = true
+            isLenient = true
+        }
     }
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/StringBuilderAdapter.kt

@@ -0,0 +1,20 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+
+@Serializer(forClass = StringBuilder::class)
+object StringBuilderAdapter : KSerializer<StringBuilder> {
+    override fun serialize(encoder: Encoder, value: StringBuilder) {
+        encoder.encodeString(value.toString())
+    }
+
+    override fun deserialize(decoder: Decoder): StringBuilder = StringBuilder(decoder.decodeString())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("StringBuilder", PrimitiveKind.STRING)
+}

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/URIAdapter.kt

@@ -1,13 +1,21 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.net.URI
 
-class URIAdapter {
-    @ToJson
-    fun toJson(uri: URI) = uri.toString()
+@Serializer(forClass = URI::class)
+object URIAdapter : KSerializer<URI> {
+    override fun serialize(encoder: Encoder, value: URI) {
+        encoder.encodeString(value.toASCIIString())
+    }
 
-    @FromJson
-    fun fromJson(s: String): URI = URI.create(s)
+    override fun deserialize(decoder: Decoder): URI = URI(decoder.decodeString())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("URI", PrimitiveKind.STRING)
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/URLAdapter.kt

@@ -0,0 +1,21 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+import java.net.URL
+
+@Serializer(forClass = URL::class)
+object URLAdapter : KSerializer<URL> {
+    override fun serialize(encoder: Encoder, value: URL) {
+        encoder.encodeString(value.toExternalForm())
+    }
+
+    override fun deserialize(decoder: Decoder): URL = URL(decoder.decodeString())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("URL", PrimitiveKind.STRING)
+}

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/UUIDAdapter.kt

@@ -1,13 +1,23 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.util.UUID
 
-class UUIDAdapter {
-    @ToJson
-    fun toJson(uuid: UUID) = uuid.toString()
+@Serializer(forClass = UUID::class)
+object UUIDAdapter : KSerializer<UUID> {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("UUID", PrimitiveKind.STRING)
 
-    @FromJson
-    fun fromJson(s: String): UUID = UUID.fromString(s)
+    override fun serialize(encoder: Encoder, value: UUID) {
+        encoder.encodeString(value.toString())
+    }
+
+    override fun deserialize(decoder: Decoder): UUID {
+        return UUID.fromString(decoder.decodeString())
+    }
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/models/Category.kt

@@ -21,7 +21,14 @@
 package org.openapitools.client.models
 
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import android.os.Parcelable
 import kotlinx.parcelize.Parcelize
 
@@ -32,13 +39,13 @@ import kotlinx.parcelize.Parcelize
  * @param name 
  */
 @Parcelize
-
+@Serializable
 data class Category (
 
-    @Json(name = "id")
+    @SerialName(value = "id")
     val id: kotlin.Long? = null,
 
-    @Json(name = "name")
+    @SerialName(value = "name")
     val name: kotlin.String? = null
 
 ) : Parcelable

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/models/ModelApiResponse.kt

@@ -21,7 +21,14 @@
 package org.openapitools.client.models
 
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import android.os.Parcelable
 import kotlinx.parcelize.Parcelize
 
@@ -33,16 +40,16 @@ import kotlinx.parcelize.Parcelize
  * @param message 
  */
 @Parcelize
-
+@Serializable
 data class ModelApiResponse (
 
-    @Json(name = "code")
+    @SerialName(value = "code")
     val code: kotlin.Int? = null,
 
-    @Json(name = "type")
+    @SerialName(value = "type")
     val type: kotlin.String? = null,
 
-    @Json(name = "message")
+    @SerialName(value = "message")
     val message: kotlin.String? = null
 
 ) : Parcelable

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/models/Order.kt

@@ -21,7 +21,14 @@
 package org.openapitools.client.models
 
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import android.os.Parcelable
 import kotlinx.parcelize.Parcelize
 
@@ -36,26 +43,26 @@ import kotlinx.parcelize.Parcelize
  * @param complete 
  */
 @Parcelize
-
+@Serializable
 data class Order (
 
-    @Json(name = "id")
+    @SerialName(value = "id")
     val id: kotlin.Long? = null,
 
-    @Json(name = "petId")
+    @SerialName(value = "petId")
     val petId: kotlin.Long? = null,
 
-    @Json(name = "quantity")
+    @SerialName(value = "quantity")
     val quantity: kotlin.Int? = null,
 
-    @Json(name = "shipDate")
+    @Contextual @SerialName(value = "shipDate")
     val shipDate: java.time.OffsetDateTime? = null,
 
     /* Order Status */
-    @Json(name = "status")
+    @SerialName(value = "status")
     val status: Order.Status? = null,
 
-    @Json(name = "complete")
+    @SerialName(value = "complete")
     val complete: kotlin.Boolean? = false
 
 ) : Parcelable {
@@ -63,12 +70,29 @@ data class Order (
     /**
      * Order Status
      *
-     * Values: placed,approved,delivered
+     * Values: placed,approved,delivered,unknownDefaultOpenApi
      */
+    @Serializable(with = OrderSerializer::class)
     enum class Status(val value: kotlin.String) {
-        @Json(name = "placed") placed("placed"),
-        @Json(name = "approved") approved("approved"),
-        @Json(name = "delivered") delivered("delivered");
+        @SerialName(value = "placed") placed("placed"),
+        @SerialName(value = "approved") approved("approved"),
+        @SerialName(value = "delivered") delivered("delivered"),
+        @SerialName(value = "unknown_default_open_api") unknownDefaultOpenApi("unknown_default_open_api");
+    }
+
+    @Serializer(forClass = Status::class)
+    internal object StatusSerializer : KSerializer<Status> {
+        override val descriptor = kotlin.String.serializer().descriptor
+
+        override fun deserialize(decoder: Decoder): Status {
+            val value = decoder.decodeSerializableValue(kotlin.String.serializer())
+            return Status.values().firstOrNull { it.value == value }
+                ?: Status.unknownDefaultOpenApi
+        }
+
+        override fun serialize(encoder: Encoder, value: Status) {
+            encoder.encodeSerializableValue(kotlin.String.serializer(), value.value)
+        }
     }
 }
 

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/models/Pet.kt

@@ -23,7 +23,14 @@ package org.openapitools.client.models
 import org.openapitools.client.models.Category
 import org.openapitools.client.models.Tag
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import android.os.Parcelable
 import kotlinx.parcelize.Parcelize
 
@@ -38,26 +45,26 @@ import kotlinx.parcelize.Parcelize
  * @param status pet status in the store
  */
 @Parcelize
-
+@Serializable
 data class Pet (
 
-    @Json(name = "name")
+    @SerialName(value = "name")
     val name: kotlin.String,
 
-    @Json(name = "photoUrls")
+    @SerialName(value = "photoUrls")
     val photoUrls: kotlin.collections.List<kotlin.String>,
 
-    @Json(name = "id")
+    @SerialName(value = "id")
     val id: kotlin.Long? = null,
 
-    @Json(name = "category")
+    @SerialName(value = "category")
     val category: Category? = null,
 
-    @Json(name = "tags")
+    @SerialName(value = "tags")
     val tags: kotlin.collections.List<Tag>? = null,
 
     /* pet status in the store */
-    @Json(name = "status")
+    @SerialName(value = "status")
     val status: Pet.Status? = null
 
 ) : Parcelable {
@@ -65,12 +72,29 @@ data class Pet (
     /**
      * pet status in the store
      *
-     * Values: available,pending,sold
+     * Values: available,pending,sold,unknownDefaultOpenApi
      */
+    @Serializable(with = PetSerializer::class)
     enum class Status(val value: kotlin.String) {
-        @Json(name = "available") available("available"),
-        @Json(name = "pending") pending("pending"),
-        @Json(name = "sold") sold("sold");
+        @SerialName(value = "available") available("available"),
+        @SerialName(value = "pending") pending("pending"),
+        @SerialName(value = "sold") sold("sold"),
+        @SerialName(value = "unknown_default_open_api") unknownDefaultOpenApi("unknown_default_open_api");
+    }
+
+    @Serializer(forClass = Status::class)
+    internal object StatusSerializer : KSerializer<Status> {
+        override val descriptor = kotlin.String.serializer().descriptor
+
+        override fun deserialize(decoder: Decoder): Status {
+            val value = decoder.decodeSerializableValue(kotlin.String.serializer())
+            return Status.values().firstOrNull { it.value == value }
+                ?: Status.unknownDefaultOpenApi
+        }
+
+        override fun serialize(encoder: Encoder, value: Status) {
+            encoder.encodeSerializableValue(kotlin.String.serializer(), value.value)
+        }
     }
 }
 

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/models/Tag.kt

@@ -21,7 +21,14 @@
 package org.openapitools.client.models
 
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import android.os.Parcelable
 import kotlinx.parcelize.Parcelize
 
@@ -32,13 +39,13 @@ import kotlinx.parcelize.Parcelize
  * @param name 
  */
 @Parcelize
-
+@Serializable
 data class Tag (
 
-    @Json(name = "id")
+    @SerialName(value = "id")
     val id: kotlin.Long? = null,
 
-    @Json(name = "name")
+    @SerialName(value = "name")
     val name: kotlin.String? = null
 
 ) : Parcelable

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/models/User.kt

@@ -21,7 +21,14 @@
 package org.openapitools.client.models
 
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import android.os.Parcelable
 import kotlinx.parcelize.Parcelize
 
@@ -38,32 +45,32 @@ import kotlinx.parcelize.Parcelize
  * @param userStatus User Status
  */
 @Parcelize
-
+@Serializable
 data class User (
 
-    @Json(name = "id")
+    @SerialName(value = "id")
     val id: kotlin.Long? = null,
 
-    @Json(name = "username")
+    @SerialName(value = "username")
     val username: kotlin.String? = null,
 
-    @Json(name = "firstName")
+    @SerialName(value = "firstName")
     val firstName: kotlin.String? = null,
 
-    @Json(name = "lastName")
+    @SerialName(value = "lastName")
     val lastName: kotlin.String? = null,
 
-    @Json(name = "email")
+    @SerialName(value = "email")
     val email: kotlin.String? = null,
 
-    @Json(name = "password")
+    @SerialName(value = "password")
     val password: kotlin.String? = null,
 
-    @Json(name = "phone")
+    @SerialName(value = "phone")
     val phone: kotlin.String? = null,
 
     /* User Status */
-    @Json(name = "userStatus")
+    @SerialName(value = "userStatus")
     val userStatus: kotlin.Int? = null
 
 ) : Parcelable