This is a release candidate for the next version with many new features to try.
It uses Kotlin 1.8.0 by default.
Json naming strategies
A long-awaited feature (#33) is available in this release.
A new interface, JsonNamingStrategy and Json configuration property namingStrategy allow
defining a transformation that is applied to all properties' names serialized by a Json instance.
There's also a predefined implementation for the most common use case: Json { namingStrategy = JsonNamingStrategy.SnakeCase }.
Check out the PR for more details and documentation.
Json unquoted literals
kotlinx-serialization-json has an API for manipulating raw Json values: functions and classes JsonObject, JsonPrimitive, etc.
In this release, there is a new addition to this API: JsonUnquotedLiteral constructor function.
It allows to produce a string that is not quoted in the Json output. This function has a lot of valuable
applications: from writing unsigned or large numbers to embedding whole Json documents without the need for re-parsing.
For an example, read the Encoding literal Json content docs.
This huge feature was contributed to us by aSemy: #2041.
Stabilization of serializer(java.lang.Type) function family
Functions serializer, serializerOrNull and extensions SerializersModule.serializer, SerializersModule.serializerOrNull
have JVM-only overloads that accept java.lang.Type. These overloads are crucial for interoperability: with them, third-party Java frameworks
like Spring, which usually rely on Java's reflection and type tokens, can retrieve KSerializer instance and use kotlinx.serialization properly.
We've removed @ExperimentalSerializationApi from these functions, and starting from 1.5.0-RC they're considered stable with all backward compatibility guarantees.
This change should improve third-party support for kotlinx.serialization in various frameworks.
See the PR for details.
Deprecations in module builders for polymorphism
Some time ago, in 1.3.2, new functions SerializersModuleBuilder.polymorphicDefaultSerializer/polymorphicDefaultDeserializer and PolymorphicModuleBuilder.defaultDeserializer were introduced
— better names allow an easier understanding of which serializers affect what part of the process.
In 1.5.0-RC, we finish the migration path: these functions are no longer experimental.
And old functions, namely SerializersModuleCollector.polymorphicDefault and PolymorphicModuleBuilder.default, are now deprecated.
See the PR for details.
Bundled Proguard rules
The kotlinx-serialization-core-jvm JAR file now includes consumer Proguard rules,
so manual Proguard configuration is no longer necessary for most of the setups.
See updated Android setup section and corresponding PRs: #2092, #2123.
Support for kotlin.Duration in HOCON format
HOCON specifies its own formatting for duration values. Starting with this release,
kotlinx-serialization-hocon is able to serialize and deserialize kotlin.Duration
using proper representation instead of the default one. Big thanks to Alexander Mikhailov
and his PRs: #2080, #2073.
Functional and performance improvements
- Make DeserializationStrategy covariant at declaration-site (#1897) (thanks to Lukellmann)
- Added support for the
kotlin.Nothingclass as built-in (#1991, #2150) - Further improve stream decoding performance (#2101)
- Introduce CharArray pooling for InputStream decoding (#2100)
- Consolidate exception messages and improve them (#2068)
Bugfixes
- Add stable hashCode()/equals() calculation to PrimitiveSerialDescriptor (#2136) (thanks to Vasily Vasilkov)
- Added a factory that creates an enum serializer with annotations on the class (#2125)
- Correctly handle situation where different serializers can be provided for the same KClass in SealedClassSerializer (#2113)
- Fixed serializers caching for parametrized types from different class loaders (#2070)