runners/maven-plugin/build.gradle

import groovy.io.FileType
import org.jetbrains.CorrectShadowPublishing
import org.jetbrains.CrossPlatformExec

import java.nio.file.Files
import java.nio.file.StandardCopyOption

apply plugin: 'kotlin'
apply plugin: 'com.github.johnrengelman.shadow'

sourceCompatibility = 1.8

tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
    kotlinOptions {
        freeCompilerArgs += "-Xjsr305=strict"
        languageVersion = "1.2"
        apiVersion = languageVersion
        jvmTarget = "1.8"
    }
}

dependencies {
    shadow project(":runners:fatjar")
    shadow "org.apache.maven:maven-core:$maven_version"
    shadow "org.apache.maven:maven-model:$maven_version"
    shadow "org.apache.maven:maven-plugin-api:$maven_version"
    shadow "org.apache.maven:maven-archiver:$maven_archiver_version"
    shadow "org.codehaus.plexus:plexus-utils:$plexus_utils_version"
    shadow "org.codehaus.plexus:plexus-archiver:$plexus_archiver_version"
    shadow "org.apache.maven.plugin-tools:maven-plugin-annotations:$maven_plugin_tools_version"
    shadow "com.github.olivergondza:maven-jdk-tools-wrapper:0.1"
}

task generatePom() {
    inputs.file(new File(projectDir, "pom.tpl.xml"))
    inputs.property("dokka_version", dokka_version)
    inputs.property("maven_version", maven_version)
    inputs.property("maven_plugin_tools_version", maven_plugin_tools_version)
    outputs.file(new File(buildDir, "pom.xml"))
    doLast {
        final pomTemplate = new File(projectDir, "pom.tpl.xml")
        final pom = new File(buildDir, "pom.xml")
        pom.text = pomTemplate.text.replace("<version>dokka_version</version>", "<version>$dokka_version</version>")
                .replace("<maven.version></maven.version>", "<maven.version>$maven_version</maven.version>")
                .replace("<version>maven-plugin-plugin</version>", "<version>$maven_plugin_tools_version</version>")
    }
}

task mergeClassOutputs doLast {
    def sourceDir = new File(buildDir, "classes/kotlin")
    def targetDir = new File(buildDir, "classes/java")

    sourceDir.eachFileRecurse FileType.ANY, {
        def filePath = it.toPath()
        def targetFilePath = targetDir.toPath().resolve(sourceDir.toPath().relativize(filePath))
        if (it.isFile()) {
            Files.move(filePath, targetFilePath, StandardCopyOption.REPLACE_EXISTING)
        } else if (it.isDirectory()) {
            targetFilePath.toFile().mkdirs()
        }
    }
}

task pluginDescriptor(type: CrossPlatformExec) {
    workingDir buildDir
    commandLine mvn, '-e', '-B', 'org.apache.maven.plugins:maven-plugin-plugin:descriptor'

    dependsOn mergeClassOutputs
}

task helpMojo(type: CrossPlatformExec) {
    workingDir buildDir
    commandLine mvn, '-e', '-B', 'org.apache.maven.plugins:maven-plugin-plugin:helpmojo'

    dependsOn mergeClassOutputs
}

helpMojo.dependsOn generatePom
sourceSets.main.java.srcDir("$buildDir/generated-sources/plugin")
compileJava.dependsOn helpMojo

pluginDescriptor.dependsOn generatePom

shadowJar {
    baseName = 'dokka-maven-plugin'
    classifier = ''
}

shadowJar.dependsOn pluginDescriptor


task sourceJar(type: Jar) {
    from sourceSets.main.allSource
}

apply plugin: 'maven-publish'

publishing {
    publications {
        dokkaMavenPlugin(MavenPublication) { MavenPublication publication ->
            artifactId = 'dokka-maven-plugin'

            artifact sourceJar {
                classifier "sources"
            }

            CorrectShadowPublishing.configure(publication, project)
        }
    }
}

bintrayPublication(project, ['dokkaMavenPlugin'])