How to write a Kotlin Compiler Plugin

ℹ️ Please be aware that the Kotlin Compiler still doesn’t have any stable API and there is no backwards compatibility guaranteed. Kotlin versions above 1.3.50 can have all totally different API.

• You can find example code here:
• Kotlin Compiler Plugin
• Kotlin Native Compiler Plugin

1. Create a normal Kotlin-Jvm Project with Gradle
2. 1)Add the compiler as dependency

repositories {
    mavenCentral()
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
   SEE BELOW
    compileOnly "com.google.auto.service:auto-service:1.0-rc6"
    kapt "com.google.auto.service:auto-service:1.0-rc6"
}

If you want to write a plugin for JS/JVM compiler, add:

       compileOnly "org.jetbrains.kotlin:kotlin-compiler-embeddable"

If you want to write a plugin for Native compiler, add:

        compileOnly "org.jetbrains.kotlin:kotlin-compiler"

2.2) Add AutoService https://github.com/google/auto/tree/master/service

You don't have use it, but AutoService will generate the META-INF file for you

    compileOnly "com.google.auto.service:auto-service:1.0-rc6"
    kapt "com.google.auto.service:auto-service:1.0-rc6"

Remember to also add Kapt apply plugin: "kotlin-kapt"

2.3) Add maven plugin

    apply plugin: "maven"

Add the configuration, and set your group,archivesBaseName and version:

group = "de.jensklingenberg"
archivesBaseName = "kotlin-compiler-plugin"
version = "0.0.1"

install {
    repositories.mavenInstaller {
        pom.artifactId = archivesBaseName
    }
}

3. Create a ComponentRegistrar Create a new Kotlin Class which implements org.jetbrains.kotlin.compiler.plugin.ComponentRegistrar

The ComponentRegistrar is the first entry class of your compiler plugin

     @AutoService(ComponentRegistrar::class)
open class CommonComponentRegistrar : ComponentRegistrar {

    override fun registerProjectComponents(
            project: MockProject,
            configuration: CompilerConfiguration
    ) {
...

If you are using AutoService add @AutoService(ComponentRegistrar::class) on top of your class

4. Use the "install" gradle task, to build your compiler plugin.

If you want to use your plugin from a Gradle plugin, take a look at * How to use a Kotlin Compiler from Gradle Plugin