🐛[Bug] [Extension] Fix KotlinX serialization problem (#733)

Author: kittinunf

buildSrc/src/main/kotlin/Constants.kt

@@ -63,7 +63,7 @@ object Fuel {
 
 // Core dependencies
 object Kotlin {
-    const val version = "1.3.61"
+    const val version = "1.3.70"
     const val stdlib = "org.jetbrains.kotlin:kotlin-stdlib:$version"
     const val plugin = "kotlin"
     const val androidPlugin = "kotlin-android"
@@ -139,7 +139,7 @@ object KotlinX {
     }
 
     object Serialization {
-        const val version = "0.14.0"
+        const val version = "0.20.0"
         const val dependency = "org.jetbrains.kotlinx:kotlinx-serialization-runtime:$version"
         const val plugin = "kotlinx-serialization"
     }

fuel-kotlinx-serialization/src/main/kotlin/com/github/kittinunf/fuel/serialization/FuelSerialization.kt

@@ -7,50 +7,51 @@ import com.github.kittinunf.fuel.core.Response
 import com.github.kittinunf.fuel.core.ResponseDeserializable
 import com.github.kittinunf.fuel.core.response
 import com.github.kittinunf.result.Result
-import kotlinx.io.InputStream
-import kotlinx.io.Reader
 import kotlinx.serialization.DeserializationStrategy
 import kotlinx.serialization.ImplicitReflectionSerializer
 import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonConfiguration
 import kotlinx.serialization.serializer
+import java.io.InputStream
+import java.io.Reader
 
 inline fun <reified T : Any> Request.responseObject(
     loader: DeserializationStrategy<T>,
-    json: Json = Json.plain,
+    json: Json = Json(JsonConfiguration.Stable),
     noinline deserializer: (Request, Response, Result<T, FuelError>) -> Unit
 ) = response(kotlinxDeserializerOf(loader, json), deserializer)
 
 @ImplicitReflectionSerializer
 inline fun <reified T : Any> Request.responseObject(
-    json: Json = Json.plain,
+    json: Json = Json(JsonConfiguration.Stable),
     noinline deserializer: (Request, Response, Result<T, FuelError>) -> Unit
 ) = responseObject(T::class.serializer(), json, deserializer)
 
 inline fun <reified T : Any> Request.responseObject(
     deserializer: ResponseHandler<T>,
     loader: DeserializationStrategy<T>,
-    json: Json = Json.plain
+    json: Json = Json(JsonConfiguration.Stable)
 ) = response(kotlinxDeserializerOf(loader, json), deserializer)
 
 @ImplicitReflectionSerializer
 inline fun <reified T : Any> Request.responseObject(
     deserializer: ResponseHandler<T>,
-    json: Json = Json.plain
+    json: Json = Json(JsonConfiguration.Stable)
 ) = responseObject(deserializer, T::class.serializer(), json)
 
 inline fun <reified T : Any> Request.responseObject(
     loader: DeserializationStrategy<T>,
-    json: Json = Json.plain
+    json: Json = Json(JsonConfiguration.Stable)
 ) = response(kotlinxDeserializerOf(loader, json))
 
 @ImplicitReflectionSerializer
 inline fun <reified T : Any> Request.responseObject(
-    json: Json = Json.plain
+    json: Json = Json(JsonConfiguration.Stable)
 ) = responseObject(T::class.serializer(), json)
 
 inline fun <reified T : Any> kotlinxDeserializerOf(
     loader: DeserializationStrategy<T>,
-    json: Json = Json.plain
+    json: Json = Json(JsonConfiguration.Stable)
 ) = object : ResponseDeserializable<T> {
     override fun deserialize(content: String): T? = json.parse(loader, content)
     override fun deserialize(reader: Reader): T? = deserialize(reader.readText())
@@ -65,5 +66,5 @@ inline fun <reified T : Any> kotlinxDeserializerOf(
 
 @ImplicitReflectionSerializer
 inline fun <reified T : Any> kotlinxDeserializerOf(
-    json: Json = Json.plain
-) = kotlinxDeserializerOf(T::class.serializer(), json)
+    json: Json = Json(JsonConfiguration.Stable)
+) = kotlinxDeserializerOf(T::class.serializer(), json)

fuel-kotlinx-serialization/src/test/kotlin/com/github/kittinunf/fuel/FuelKotlinxSerializationTest.kt

@@ -10,7 +10,7 @@ import com.github.kittinunf.fuel.test.MockHttpTestCase
 import com.github.kittinunf.result.Result
 import kotlinx.serialization.ImplicitReflectionSerializer
 import kotlinx.serialization.Serializable
-import kotlinx.serialization.list
+import kotlinx.serialization.builtins.list
 import org.hamcrest.CoreMatchers.equalTo
 import org.hamcrest.CoreMatchers.instanceOf
 import org.hamcrest.CoreMatchers.isA