Provide a DSL for publication settings (#1869)

* Provide a DSL for publication settings
* Rename DSL method publication -> mavenPublication
* Fix gradle task input/output validation

 #KT-26771 fixed.

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/KotlinMultiplatformPlugin.kt

@@ -126,6 +126,9 @@ class KotlinMultiplatformPlugin(
                 }
 
                 variant.publicationDelegate = variantPublication
+                (target as AbstractKotlinTarget).publicationConfigureActions.all {
+                    it.execute(variantPublication)
+                }
             }
         }
 

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/kotlinTargets.kt

@@ -4,6 +4,9 @@
  */
 package org.jetbrains.kotlin.gradle.plugin.mpp
 
+import groovy.lang.Closure
+import org.gradle.api.Action
+import org.gradle.api.DomainObjectSet
 import org.gradle.api.NamedDomainObjectContainer
 import org.gradle.api.Project
 import org.gradle.api.artifacts.Dependency
@@ -11,6 +14,9 @@ import org.gradle.api.attributes.Attribute
 import org.gradle.api.attributes.AttributeContainer
 import org.gradle.api.internal.component.UsageContext
 import org.gradle.api.plugins.JavaPlugin
+import org.gradle.api.publish.maven.MavenPublication
+import org.gradle.util.ConfigureUtil
+import org.gradle.util.WrapUtil
 import org.jetbrains.kotlin.gradle.plugin.*
 import org.jetbrains.kotlin.gradle.utils.isGradleVersionAtLeast
 import org.jetbrains.kotlin.gradle.utils.lowerCamelCaseName
@@ -61,6 +67,17 @@ abstract class AbstractKotlinTarget (
                     runtimeElementsConfigurationName
                 )
             ) else emptyList()
+
+    @Suppress("UNCHECKED_CAST")
+    internal val publicationConfigureActions =
+        WrapUtil.toDomainObjectSet(Action::class.java) as DomainObjectSet<Action<MavenPublication>>
+
+    override fun mavenPublication(action: Action<MavenPublication>) {
+        publicationConfigureActions.add(action)
+    }
+
+    override fun mavenPublication(action: Closure<Unit>) =
+        mavenPublication(ConfigureUtil.configureUsing(action))
 }
 
 internal fun KotlinTarget.disambiguateName(simpleName: String) =

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/KotlinNativeTasks.kt

@@ -108,8 +108,7 @@ open class KotlinNativeCompile : AbstractCompile() {
         @InputFiles get() = compilation.compileDependencyFiles
 
     private val friendModule: FileCollection?
-        // It's already taken into account in libraries
-        @Internal get() = compilation.friendCompilation?.output
+        get() = compilation.friendCompilation?.output
 
     override fun getClasspath(): FileCollection = libraries
     override fun setClasspath(configuration: FileCollection?) {