Build: Migrate plugin markers to maven-publish publication

buildSrc/build.gradle.kts

@@ -97,6 +97,7 @@ repositories {
 dependencies {
     implementation(kotlin("stdlib", embeddedKotlinVersion))
     implementation("org.jetbrains.kotlin:kotlin-build-gradle-plugin:0.0.17")
+    implementation("com.gradle.publish:plugin-publish-plugin:0.11.0")
 
     implementation("net.rubygrapefruit:native-platform:${property("versions.native-platform")}")
     implementation("net.rubygrapefruit:native-platform-windows-amd64:${property("versions.native-platform")}")

buildSrc/src/main/kotlin/pluginMarkers.kt

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+import com.gradle.publish.PluginBundleExtension
+import com.gradle.publish.PluginConfig
+import org.gradle.api.Project
+import org.gradle.api.publish.PublicationContainer
+import org.gradle.api.publish.PublishingExtension
+import org.gradle.api.publish.maven.MavenPublication
+import org.gradle.api.tasks.bundling.Jar
+import org.gradle.kotlin.dsl.*
+import plugins.KotlinBuildPublishingPlugin
+
+internal const val PLUGIN_MARKER_SUFFIX = ".gradle.plugin"
+
+fun Project.publishPluginMarkers(withEmptyJars: Boolean = true) {
+    val pluginDevelopment = extensions.getByType<PluginBundleExtension>()
+    val publishingExtension = extensions.getByType<PublishingExtension>()
+    val mainPublication = publishingExtension.publications[KotlinBuildPublishingPlugin.PUBLICATION_NAME] as MavenPublication
+
+    pluginDevelopment.plugins.forEach { declaration ->
+        val markerPublication = createMavenMarkerPublication(declaration, mainPublication, publishingExtension.publications)
+        if (withEmptyJars) {
+            addEmptyJarArtifacts(markerPublication)
+        }
+    }
+}
+
+fun Project.addEmptyJarArtifacts(publication: MavenPublication) {
+    val emptyJar = getOrCreateTask<Jar>("emptyJar") { }
+    publication.artifact(emptyJar.get()) { }
+    publication.artifact(emptyJar.get()) { classifier = "sources" }
+    publication.artifact(emptyJar.get()) { classifier = "javadoc" }
+}
+
+// Based on code from `java-gradle-plugin`
+// https://github.com/gradle/gradle/blob/v6.4.0/subprojects/plugin-development/src/main/java/org/gradle/plugin/devel/plugins/MavenPluginPublishPlugin.java#L84
+private fun createMavenMarkerPublication(
+    declaration: PluginConfig,
+    coordinates: MavenPublication,
+    publications: PublicationContainer
+): MavenPublication {
+    return publications.create<MavenPublication>(declaration.name.toString() + "PluginMarkerMaven") {
+        val pluginId: String = declaration.id
+        artifactId = pluginId + PLUGIN_MARKER_SUFFIX
+        groupId = pluginId
+        pom.withXml {
+            val root = asElement()
+            val document = root.ownerDocument
+            val dependencies = root.appendChild(document.createElement("dependencies"))
+            val dependency = dependencies.appendChild(document.createElement("dependency"))
+            val groupId = dependency.appendChild(document.createElement("groupId"))
+            groupId.textContent = coordinates.groupId
+            val artifactId = dependency.appendChild(document.createElement("artifactId"))
+            artifactId.textContent = coordinates.artifactId
+            val version = dependency.appendChild(document.createElement("version"))
+            version.textContent = coordinates.version
+        }
+
+        pom.name.set(declaration.displayName)
+        pom.description.set(declaration.description)
+    }
+}