Prepare 1.10.0-RC release

- Update to Kotlin 2.3 stable
- Update artifacts.txt contents for consistency.

Author: sandwwraith

CHANGELOG.md

@@ -1,3 +1,61 @@
+1.10.0-RC / 2025-12-18
+==================
+
+This is a release candidate for 1.10.0 based on Kotlin 2.3.0. It stabilizes a set of frequently used JSON APIs and builder options,
+adopts a new 'Return Value Checker' Kotlin feature, and provides a lot of improvements and bug fixes.
+
+## Stabilization of APIs
+
+kotlinx-serialization 1.10 and subsequent releases will be focused on stabilization of existing APIs.
+The following APIs and configuration options are no longer experimental because they're widely used without any known major issues:
+
+* `Json` configuration options: `decodeEnumsCaseInsensitive`, `allowTrailingComma`, `allowComments`, and `prettyPrintIndent`. (#3100)
+* `@EncodeDefault` annotation and its modes. (#3106)
+* `JsonUnquotedLiteral` constructor function (#2900)
+* `JsonPrimitive` constructor function overloads that accept unsigned types. (#3117)
+* JSON DSL functions on `JsonElement` with `Nothing?` overloads. (#3117)
+
+## Readiness for return value checker
+
+Kotlin 2.3.0 [introduces a new feature](https://kotlinlang.org/docs/whatsnew23.html#unused-return-value-checker) aimed 
+at helping you to catch bugs related to the accidentally ignored return value of the function.
+kotlinx-serialization 1.10.0-RC code is fully marked for this feature, meaning that you
+can get warnings for unused function calls like `Json.encodeToString(...)`.
+To get the warnings, the feature has to be enabled in your project as [described here](https://kotlinlang.org/docs/unused-return-value-checker.html#configure-the-unused-return-value-checker).
+
+## Polymorphism improvements
+
+Polymorphic serialization received a couple of improvements in this release:
+
+New `subclassesOfSealed` utility to automatically register sealed subclasses serializers in polymorphic modules (#2201).
+Use it in your `SerializersModule` when configuring a polymorphic hierarchy which contains both abstract and sealed classes.
+[For example](https://github.com/Kotlin/kotlinx.serialization/issues/2199), when root of your hierarchy is an `inteface`, but most of your inheritors are `sealed` classes.
+The new function will register all known sealed subclasses for you, so you don’t need to list them one by one.
+This makes writing your `SerializerModule`s much faster and simpler.
+Big thanks to [Paul de Vrieze](https://github.com/pdvrieze) for contributing this feature.
+
+Class discriminator conflict check rework (#3105).
+If a payload already contains a property with the same name as the configured discriminator (for example, `type`),
+it is called a class discriminator conflict. 
+To produce a correct output and allow more inputs to be deserialized at the same time, the following changes were made:
+* Conflicts introduced by `JsonNamingStrategy` transformations are now detected during serialization as well and will cause `SerializationException`.
+It also affects non-polymorphic classes.
+* Conflicts from `ClassDisciminatorMode.ALL_JSON_OBJECTS` and `SerializersModuleBuilder.polymorphicDefaultSerializer` are also detected.
+* It is allowed to deserialize such a conflicting key for both sealed and open polymorphic hierarchies. 
+Previously, it was possible in the sealed hierarchies alone due to missing assertion. See #1664 for details.
+
+## General improvements
+
+  * Add `.serialName` to `MissingFieldException` for clearer diagnostics. (#3114)
+  * Generate unique `Automatic-Module-Name` entries for metadata JARs. (#3109)
+  * Revised ProGuard rules and added R8 tests. (#3041)
+  * CBOR: Improved error message when a byte string/array type mismatch is encountered. (#3052)
+
+## Bugfixes
+
+  * Fix the type in the `BIGNUM_NEGATIVE` tag name. (#3090)
+  * CBOR: Fix various bugs in the decoder implementation to be more strict and consistent with the specification.
+
 1.9.0 / 2025-06-27
 ==================
 

README.md

@@ -4,8 +4,8 @@
 [![JetBrains official project](https://jb.gg/badges/official.svg)](https://confluence.jetbrains.com/display/ALL/JetBrains+on+GitHub)
 [![GitHub license](https://img.shields.io/badge/license-Apache%20License%202.0-blue.svg?style=flat)](http://www.apache.org/licenses/LICENSE-2.0)
 [![TeamCity build](https://img.shields.io/teamcity/http/teamcity.jetbrains.com/s/KotlinTools_KotlinxSerialization_Ko.svg)](https://teamcity.jetbrains.com/viewType.html?buildTypeId=KotlinTools_KotlinxSerialization_Ko&guest=1)
-[![Kotlin](https://img.shields.io/badge/kotlin-2.2.0-blue.svg?logo=kotlin)](http://kotlinlang.org)
-[![Maven Central](https://img.shields.io/maven-central/v/org.jetbrains.kotlinx/kotlinx-serialization-core/1.9.0)](https://central.sonatype.com/artifact/org.jetbrains.kotlinx/kotlinx-serialization-core/1.9.0)
+[![Kotlin](https://img.shields.io/badge/kotlin-2.3.0-blue.svg?logo=kotlin)](http://kotlinlang.org)
+[![Maven Central](https://img.shields.io/maven-central/v/org.jetbrains.kotlinx/kotlinx-serialization-core/1.10.0-RC)](https://central.sonatype.com/artifact/org.jetbrains.kotlinx/kotlinx-serialization-core/1.10.0-RC)
 [![KDoc link](https://img.shields.io/badge/API_reference-KDoc-blue)](https://kotlinlang.org/api/kotlinx.serialization/)
 [![Slack channel](https://img.shields.io/badge/chat-slack-blue.svg?logo=slack)](https://kotlinlang.slack.com/messages/serialization/)
 
@@ -94,17 +94,17 @@ Kotlin DSL:
 
 ```kotlin
 plugins {
-    kotlin("jvm") version "2.2.0" // or kotlin("multiplatform") or any other kotlin plugin
-    kotlin("plugin.serialization") version "2.2.0"
+    kotlin("jvm") version "2.3.0" // or kotlin("multiplatform") or any other kotlin plugin
+    kotlin("plugin.serialization") version "2.3.0"
 }
 ```       
 
 Groovy DSL:
 
 ```gradle
 plugins {
-    id 'org.jetbrains.kotlin.multiplatform' version '2.2.0'
-    id 'org.jetbrains.kotlin.plugin.serialization' version '2.2.0'
+    id 'org.jetbrains.kotlin.multiplatform' version '2.3.0'
+    id 'org.jetbrains.kotlin.plugin.serialization' version '2.3.0'
 }
 ```
 
@@ -122,7 +122,7 @@ buildscript {
     repositories { mavenCentral() }
 
     dependencies {
-        val kotlinVersion = "2.2.0"
+        val kotlinVersion = "2.3.0"
         classpath(kotlin("gradle-plugin", version = kotlinVersion))
         classpath(kotlin("serialization", version = kotlinVersion))
     }
@@ -133,7 +133,7 @@ Groovy DSL:
 
 ```gradle
 buildscript {
-    ext.kotlin_version = '2.2.0'
+    ext.kotlin_version = '2.3.0'
     repositories { mavenCentral() }
 
     dependencies {
@@ -163,7 +163,7 @@ repositories {
 }
 
 dependencies {
-    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.9.0")
+    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.10.0-RC")
 }
 ```
 
@@ -175,7 +175,7 @@ repositories {
 }
 
 dependencies {
-    implementation "org.jetbrains.kotlinx:kotlinx-serialization-json:1.9.0"
+    implementation "org.jetbrains.kotlinx:kotlinx-serialization-json:1.10.0-RC"
 }
 ```
 
@@ -265,8 +265,8 @@ Ensure the proper version of Kotlin and serialization version:
 
 ```xml
 <properties>
-    <kotlin.version>2.2.0</kotlin.version>
-    <serialization.version>1.9.0</serialization.version>
+    <kotlin.version>2.3.0</kotlin.version>
+    <serialization.version>1.10.0-RC</serialization.version>
 </properties>
 ```
 

RELEASING.md

@@ -37,9 +37,7 @@ If review is not required, commit directly to `dev`.
      * On 'Changes' tab, select `dev` branch and corresponding commit.
      * On 'Parameters' tab, find 'Deploy version' and fill in with `<version>`.
 
-4. In [Sonatype](https://oss.sonatype.org/#stagingRepositories) admin interface:
-   * Close the repository and wait for it to verify.
-   * Release it.
+4. !Temporary! Ask the owner of Maven Central access credentials to publish artifacts on Maven Central.
 
 5. Set a new value for [`KOTLINX_SERIALIZATION_RELEASE_TAG`](https://github.com/JetBrains/kotlin-web-site/blob/master/.teamcity/BuildParams.kt),
    creating a pull request in the website's repository. To find out why it is needed, [read this](#kotlinxserializationreleasetag).

gradle.properties

@@ -7,7 +7,7 @@ version=1.10.0-SNAPSHOT
 jdk_toolchain_version=11
 
 # This version takes precedence if 'bootstrap' property passed to project
-kotlin.version.snapshot=2.2.255-SNAPSHOT
+kotlin.version.snapshot=2.3.255-SNAPSHOT
 # Also set kotlin.native.home to your $kotlin_project$/kotlin-native/dist if you want to use snapshot Native
 #kotlin.native.home=
 

gradle/artifacts.txt

@@ -112,6 +112,7 @@ kotlinx-serialization-json-okio-wasm-js
 kotlinx-serialization-json-okio-wasm-wasi
 kotlinx-serialization-json-okio-watchosarm32
 kotlinx-serialization-json-okio-watchosarm64
+kotlinx-serialization-json-okio-watchosdevicearm64
 kotlinx-serialization-json-okio-watchossimulatorarm64
 kotlinx-serialization-json-okio-watchosx64
 kotlinx-serialization-json-tvosarm64

gradle/libs.versions.toml

@@ -1,5 +1,5 @@
 [versions]
-kotlin = "2.3.0-Beta2"
+kotlin = "2.3.0"
 kover = "0.8.2"
 dokka = "2.0.0"
 knit = "0.5.0"

integration-test/gradle.properties

@@ -2,7 +2,7 @@
 # Copyright 2017-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
 #
 
-mainKotlinVersion=2.3.0-Beta2
+mainKotlinVersion=2.3.0
 mainLibVersion=1.10.0-SNAPSHOT
 
 kotlin.code.style=official