How to use a Kotlin Compiler Plugin from Gradle Plugin

• You can find example code here: Gradle Plugin

1. Create a usual Kotlin-Jvm project
2. Add dependencies:

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
    compile "org.jetbrains.kotlin:kotlin-gradle-plugin-api:1.3.50"
    compileOnly "com.google.auto.service:auto-service:1.0-rc6"
    kapt "com.google.auto.service:auto-service:1.0-rc6"
}

3. Apply the plugins

apply plugin: "java-gradle-plugin"
apply plugin: "kotlin-kapt"
apply plugin: "maven"

Create a class which implements org.gradle.api.Plugin

open class MpAptGradlePlugin : org.gradle.api.Plugin<Project> {
    override fun apply(project: Project) {
			//You don't need to do something here
    }
}

Create a class which implements KotlinGradleSubplugin

@AutoService(KotlinGradleSubplugin::class) // don't forget!
class MpAptGradleSubplugin : KotlinGradleSubplugin<AbstractCompile> {
 ...
}

 override fun apply(...) : List<SubpluginOption>

You can return an emptyList() here

  override fun isApplicable(project: Project, task: AbstractCompile) =
            project.plugins.hasPlugin(MpAptGradlePlugin::class.java)

Here you decide when your plugin is applicable.

     override fun getCompilerPluginId(): String = "MpAptPlugin"

If you want to pass command line arguments to your compiler plugin the pluginid needs to match with the pluginId in your CommandLineProcessor

    override fun getPluginArtifact(): SubpluginArtifact = SubpluginArtifact(
            groupId = "de.jensklingenberg",
            artifactId = "kotlin-compiler-plugin",
            version = "0.0.1" // remember to bump this version before any release!
    )

Here you need to set the correct values of the compiler plugin that you want to start. You can only start compiler plugins for Kotlin JS/JVM here

   override fun getNativeCompilerPluginArtifact() = SubpluginArtifact(
            groupId = "de.jensklingenberg",
            artifactId = "kotlin-compiler-native-plugin",
            version = "0.0.1" // remember to bump this version before any release!
    )

the same as above, but here you can only set Kotlin Native Plugins

5. Add configuration to your build.gradle

  
group = "de.jensklingenberg"
archivesBaseName = "mpapt-gradle"
version = "1.0.0"

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

gradlePlugin {
    plugins {
        simplePlugin {
            id = "de.jensklingenberg.mpapt" // users will do `apply plugin: "de.jensklingenberg.mpapt"`
            implementationClass = "de.jensklingenberg.mpapt.MpAptGradlePlugin" // entry-point class
        }
    }
}

6. Use the install task to create the plugin