Kotlin bolsters K2 compiler plugin support, WebAssembly debugging

Kotlin 2.1.20, just released as the latest version of JetBrains’ cross-platform programming language, improves both plugin support for the K2 compiler and Kotlin/Wasm debugging.

The Kotlin update was announced March 20. Instructions on updating can be found at kotlinlang.org.

For the K2 compiler, Kotlin 2.1.20 brings updates to the new kapt and Lombok compiler plugins, including having the kapt compiler plugin enabled by default for all projects. Kotlin’s builders have been improving performance of the kapt annotation processing compiler dating back to Kotlin 1.9.20, from October 2023. But kapt has been in maintenance mode, meaning JetBrains keeps it up-to-date with Kotlin and Java but has no plans to add new features. The experimental Lombok plugin, for using Java Lombok declarations, now supports the @SuperBuilder annotation, thus making it easier to create builders for class hierarchies.

With Kotlin/Wasm, for compiling Kotlin code into the WebAssembly format, Kotlin 2.1.20 improves property usage and debugging. Custom formatters now work out of the box in development builds and DWARF (debugging with arbitrary record format) facilitates code inspection. DWARF data can be embedded into the embedded WebAssembly binary. Many debuggers and virtual machines can read this data to provide insights into compiled code.

Also in Kotlin 2.1.20:

The Compose compiler relaxes some restrictions on @Composable functions introduced in prior releases. Also, the Compose compiler Gradle plugin is set to include source information by default, aligning the behavior on all platforms with Android.

The standard library introduces experimental features including common atomic types, improved support for UUIDs (Universally Unique Identifiers), and new time-tracking functionality.

For Kotlin/Native, a new inlining optimization pass is being introduced.

Kotlin plugins supporting Kotlin 2.1.20 are bundled into the latest IntelliJ IDEA and Android Studio IDEs.

For Kotlin Multiplatform, a new DSL (domain specific language) replaces the Gradle Application plugin.