Kore

Kore is a fork of the Kotlin/Native compiler and runtime. Its goal is runtime performance and memory use competitive with C/C++, while remaining a drop-in replacement for Kotlin/Native. Kore is a project by Sona Interactive, Inc.

Kore is based on JetBrains/kotlin tag v2.4.21 and is licensed under Apache-2.0. See NOTICE.txt. Kore is not affiliated with JetBrains or the Kotlin Foundation.

Using Kore from a Gradle project

Apply the gg.sona.kore settings plugin in a Kotlin Multiplatform project that uses KGP 2.4.21 (settings.gradle.kts):

pluginManagement {
    repositories {
        maven("https://maven.cloverclient.com/releases") { content { includeGroupAndSubgroups("gg.sona.kore") } }
        gradlePluginPortal()
    }
}

plugins {
    id("gg.sona.kore") version "0.1.0"
}

On the first build, the plugin downloads the Kore distribution for the host (gg.sona.kore:kore-native-prebuilt), checks it and unpacks it under ~/.konan/kore/<version>. Then it sets kotlin.native.home on every project, so KGP logs A user-provided Kotlin/Native distribution configured: … and compiles with Kore. Later builds, offline ones included, reuse the installation. The plugin's version is the Kore version it installs. Published third-party klibs, such as kotlinx-coroutines-core, resolve and link as usual.

Gradle properties of the plugin:

Property	Effect
kore.version	Kore version to install, instead of the plugin's own.
kore.enabled=false	Leaves the build on upstream Kotlin/Native.
kotlin.native.home	Uses that distribution (e.g. a local Kore build) and installs nothing.
kore.distribution=regular	The distribution without prebuilt platform libraries.
kore.install.dir	Where distributions are installed (default $KONAN_DATA_DIR or ~/.konan).
kore.maven.url	The Maven repository holding the distributions.
koreMavenUsername, koreMavenPassword	Credentials, for a repository that needs them.

konan.data.dir makes KGP ignore kotlin.native.home, so the plugin fails the build when it is set.

To use a local build of Kore instead (see below), set kotlin.native.home=/path/to/Kore/kotlin-native/dist in gradle.properties, with or without the plugin.

Building

Requirements: Windows, Linux or macOS host; internet access on the first build. Gradle provisions JDK 21 itself, and the LLVM/MinGW toolchains are downloaded to ~/.konan/dependencies.

Build the compiler, runtime and stdlib for the host:

./gradlew :kotlin-native:dist

Build the host's platform libraries (on Windows: posix, windows, opengl32, zlib, …):

./gradlew :kotlin-native:distPlatformLibs

The output goes to kotlin-native/dist. Use :kotlin-native:crossDist to add cross-compilation targets (Linux and Android from any host). Apple targets need a macOS host with Xcode.

Releasing

Pushing a v<version> tag runs the Release workflow (.github/workflows/release.yml). It builds the bundles on Windows, Linux and macOS, then publishes gg.sona.kore:kore-native, gg.sona.kore:kore-native-prebuilt (classifier <os>-<arch>) and the gg.sona.kore Gradle plugin, all at that version, to the Kore Maven repository. The workflow needs the repository secrets KORE_MAVEN_USERNAME and KORE_MAVEN_PASSWORD.

To publish this host's bundles and the plugin by hand, with koreMavenUsername and koreMavenPassword in ~/.gradle/gradle.properties:

./gradlew :kotlin-native:publishKoreToMavenRepository -Pkore.version=<version>
./gradlew -p gradle-plugin publish -Pkore.version=<version>