Add some API interfaces for Gradle PM20 entities in the API module

libraries/tools/kotlin-gradle-plugin-api/build.gradle.kts

@@ -16,6 +16,7 @@ dependencies {
 
     compileOnly(gradleApi())
     compileOnly("com.android.tools.build:gradle:3.4.0")
+    compileOnly(project(":kotlin-project-model"))
 }
 
 pill {

libraries/tools/kotlin-gradle-plugin-api/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinCompilationData.kt

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2010-2021 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.
+ */
+
+package org.jetbrains.kotlin.gradle.plugin.mpp.pm20
+
+import org.gradle.api.Project
+import org.gradle.api.file.FileCollection
+import org.gradle.api.file.SourceDirectorySet
+import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
+import org.jetbrains.kotlin.gradle.plugin.KotlinCompilationOutput
+import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
+import org.jetbrains.kotlin.gradle.plugin.LanguageSettingsBuilder
+
+interface KotlinCompilationData<T : KotlinCommonOptions> {
+    val project: Project
+    val owner: Any?
+
+    val compilationPurpose: String
+    val compilationClassifier: String?
+
+    val kotlinSourceDirectoriesByFragmentName: Map<String, SourceDirectorySet>
+    val compileKotlinTaskName: String
+    val compileAllTaskName: String
+
+    val compileDependencyFiles: FileCollection
+    val output: KotlinCompilationOutput
+
+    val languageSettings: LanguageSettingsBuilder
+    val platformType: KotlinPlatformType
+
+    val moduleName: String
+    val ownModuleName: String
+
+    val kotlinOptions: T
+
+    val friendPaths: Iterable<FileCollection>
+}
+
+interface KotlinVariantCompilationData<T : KotlinCommonOptions> : KotlinCompilationData<T> {
+    override val owner: KotlinGradleVariant
+
+    override val project: Project get() = owner.containingModule.project
+
+    override val compilationPurpose: String
+        get() = owner.containingModule.name
+
+    override val compilationClassifier: String
+        get() = owner.name
+
+    override val output: KotlinCompilationOutput
+        get() = owner.compilationOutputs
+
+    override val compileKotlinTaskName: String
+
+    override val compileAllTaskName: String
+
+    override val kotlinSourceDirectoriesByFragmentName: Map<String, SourceDirectorySet>
+
+    override val compileDependencyFiles: FileCollection
+        get() = owner.compileDependencyFiles
+
+    override val languageSettings: LanguageSettingsBuilder
+        get() = owner.languageSettings
+
+    override val platformType: KotlinPlatformType
+        get() = owner.platformType
+
+    override val ownModuleName: String
+}

libraries/tools/kotlin-gradle-plugin-api/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinGradleFragment.kt

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2010-2021 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.
+ */
+
+package org.jetbrains.kotlin.gradle.plugin.mpp.pm20
+
+import groovy.lang.Closure
+import org.gradle.api.Named
+import org.gradle.api.NamedDomainObjectProvider
+import org.gradle.api.Project
+import org.gradle.api.file.SourceDirectorySet
+import org.gradle.util.ConfigureUtil
+import org.jetbrains.kotlin.gradle.plugin.HasKotlinDependencies
+import org.jetbrains.kotlin.gradle.plugin.LanguageSettingsBuilder
+import org.jetbrains.kotlin.project.model.KotlinModuleFragment
+
+interface KotlinGradleFragment : KotlinModuleFragment, HasKotlinDependencies, Named {
+    override val kotlinSourceRoots: SourceDirectorySet
+
+    override val containingModule: KotlinGradleModule
+
+    override fun getName(): String = fragmentName
+
+    // TODO pull up to KotlinModuleFragment
+    // FIXME apply to compilation
+    // FIXME check for consistency
+    val languageSettings: LanguageSettingsBuilder
+
+    val project: Project
+        get() = containingModule.project
+
+    fun refines(other: KotlinGradleFragment)
+
+    fun refines(other: NamedDomainObjectProvider<KotlinGradleFragment>)
+
+    override fun dependencies(configureClosure: Closure<Any?>) =
+        dependencies f@{ ConfigureUtil.configure(configureClosure, this@f) }
+
+    companion object {
+        const val COMMON_FRAGMENT_NAME = "common"
+    }
+
+    /** This configuration includes the dependencies from the refines-parents */
+    val transitiveApiConfigurationName: String
+
+    /** This configuration includes the dependencies from the refines-parents */
+    val transitiveImplementationConfigurationName: String
+
+    override val relatedConfigurationNames: List<String>
+        get() = super.relatedConfigurationNames +
+                // TODO: resolvable metadata configurations?
+                listOf(transitiveApiConfigurationName, transitiveImplementationConfigurationName)
+}

libraries/tools/kotlin-gradle-plugin-api/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinGradleModule.kt

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2010-2021 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.
+ */
+
+package org.jetbrains.kotlin.gradle.plugin.mpp.pm20
+
+import groovy.lang.Closure
+import org.gradle.api.ExtensiblePolymorphicDomainObjectContainer
+import org.gradle.api.Named
+import org.gradle.api.NamedDomainObjectSet
+import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.plugin.HasKotlinDependencies
+import org.jetbrains.kotlin.gradle.plugin.KotlinDependencyHandler
+import org.jetbrains.kotlin.project.model.KotlinModule
+
+interface KotlinGradleModule : KotlinModule, Named, HasKotlinDependencies {
+    val project: Project
+    val moduleClassifier: String?
+
+    override val fragments: ExtensiblePolymorphicDomainObjectContainer<KotlinGradleFragment>
+
+    // TODO DSL & build script model: find a way to create a flexible typed view on fragments?
+    override val variants: NamedDomainObjectSet<KotlinGradleVariant>
+
+    val isPublic: Boolean
+
+    fun ifMadePublic(action: () -> Unit)
+
+    fun makePublic()
+
+    companion object {
+        const val MAIN_MODULE_NAME = "main"
+        const val TEST_MODULE_NAME = "test"
+    }
+
+    override fun getName(): String = when (val classifier = moduleClassifier) {
+        null -> MAIN_MODULE_NAME
+        else -> classifier
+    }
+
+    // DSL
+
+    val common: KotlinGradleFragment
+        get() = fragments.getByName(KotlinGradleFragment.COMMON_FRAGMENT_NAME)
+
+    fun common(configure: KotlinGradleFragment.() -> Unit) =
+        common.configure()
+
+    override fun dependencies(configure: KotlinDependencyHandler.() -> Unit) =
+        common.dependencies(configure)
+
+    override fun dependencies(configureClosure: Closure<Any?>) =
+        common.dependencies(configureClosure)
+
+    override val apiConfigurationName: String
+        get() = common.apiConfigurationName
+
+    override val implementationConfigurationName: String
+        get() = common.implementationConfigurationName
+
+    override val compileOnlyConfigurationName: String
+        get() = common.compileOnlyConfigurationName
+
+    override val runtimeOnlyConfigurationName: String
+        get() = common.runtimeOnlyConfigurationName
+}

libraries/tools/kotlin-gradle-plugin-api/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinGradleVariant.kt

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2010-2021 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.
+ */
+
+package org.jetbrains.kotlin.gradle.plugin.mpp.pm20
+
+import org.gradle.api.file.ConfigurableFileCollection
+import org.gradle.api.file.FileCollection
+import org.gradle.api.publish.maven.MavenPublication
+import org.gradle.api.tasks.TaskProvider
+import org.gradle.api.tasks.bundling.AbstractArchiveTask
+import org.jetbrains.kotlin.gradle.plugin.KotlinCompilationOutput
+import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
+import org.jetbrains.kotlin.project.model.KotlinModuleVariant
+
+interface KotlinGradleVariant : KotlinGradleFragment, KotlinModuleVariant {
+    val platformType: KotlinPlatformType
+
+    // TODO generalize with KotlinCompilation?
+    val compileDependencyConfigurationName: String
+
+    var compileDependencyFiles: FileCollection
+
+    // TODO rewrite using our own artifacts API?
+    val compilationOutputs: KotlinCompilationOutput
+
+    // TODO rewrite using our own artifacts API
+    val sourceArchiveTask: TaskProvider<AbstractArchiveTask>
+
+    // TODO generalize exposing outputs: what if a variant has more than one such configurations or none?
+    val apiElementsConfigurationName: String
+
+    val gradleVariantNames: Set<String>
+}
+
+interface KotlinGradleVariantWithRuntime : KotlinGradleVariant {
+    // TODO deduplicate with KotlinCompilation?
+    val runtimeDependencyConfigurationName: String
+
+    var runtimeDependencyFiles: FileCollection
+
+    val runtimeFiles: ConfigurableFileCollection
+
+    // TODO generalize exposing outputs: what if a variant has more than one such configurations or none?
+    val runtimeElementsConfigurationName: String
+}
+
+interface KotlinNativeVariant : KotlinGradleVariant {
+    override val platformType: KotlinPlatformType
+        get() = KotlinPlatformType.native
+
+    var enableEndorsedLibraries: Boolean
+}
+
+interface SingleMavenPublicationHolder {
+    fun assignMavenPublication(publication: MavenPublication)
+    val defaultPublishedModuleSuffix: String?
+    val publishedMavenModuleCoordinates: PublishedModuleCoordinatesProvider
+}
+
+interface PublishedModuleCoordinatesProvider {
+    val group: String
+    val name: String
+    val version: String
+    val capabilities: Iterable<String>
+}

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

@@ -17,9 +17,7 @@ import org.gradle.api.attributes.AttributeContainer
 import org.jetbrains.kotlin.gradle.dsl.*
 import org.jetbrains.kotlin.gradle.dsl.kotlinExtension
 import org.jetbrains.kotlin.gradle.dsl.multiplatformExtensionOrNull
-import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
-import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet
-import org.jetbrains.kotlin.gradle.plugin.KotlinTarget
+import org.jetbrains.kotlin.gradle.plugin.*
 import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.*
 import org.jetbrains.kotlin.gradle.plugin.sources.KotlinDependencyScope
 import org.jetbrains.kotlin.gradle.plugin.sources.getVisibleSourceSetsFromAssociateCompilations
@@ -32,50 +30,52 @@ class ProjectStructureMetadataModuleBuilder {
         component: ResolvedComponentResult,
         metadata: KotlinProjectStructureMetadata
     ): KotlinModule {
-        return ExternalImportedKotlinModule(
-            BasicKotlinModule(component.toModuleIdentifier()).apply {
-                metadata.sourceSetNamesByVariantName.keys.forEach { variantName ->
-                    fragments.add(BasicKotlinModuleVariant(this@apply, variantName))
+        val moduleData = BasicKotlinModule(component.toSingleModuleIdentifier()).apply {
+            metadata.sourceSetNamesByVariantName.keys.forEach { variantName ->
+                fragments.add(BasicKotlinModuleVariant(this@apply, variantName))
+            }
+            fun fragment(sourceSetName: String): BasicKotlinModuleFragment {
+                if (fragments.none { it.fragmentName == sourceSetName })
+                    fragments.add(BasicKotlinModuleFragment(this@apply, sourceSetName))
+                return fragmentByName(sourceSetName)
+            }
+            metadata.sourceSetNamesByVariantName.forEach { (variantName, sourceSets) ->
+                val variant = fragmentByName(variantName)
+                sourceSets.forEach { sourceSetName ->
+                    variant.directRefinesDependencies.add(fragment(sourceSetName))
                 }
-                fun fragment(sourceSetName: String): BasicKotlinModuleFragment {
-                    if (fragments.none { it.fragmentName == sourceSetName })
-                        fragments.add(BasicKotlinModuleFragment(this@apply, sourceSetName))
-                    return fragmentByName(sourceSetName)
-                }
-                metadata.sourceSetNamesByVariantName.forEach { (variantName, sourceSets) ->
-                    val variant = fragmentByName(variantName)
-                    sourceSets.forEach { sourceSetName ->
-                        variant.directRefinesDependencies.add(fragment(sourceSetName))
-                    }
-                }
-                metadata.sourceSetModuleDependencies.forEach { (sourceSetName, dependencies) ->
-                    val fragment = fragment(sourceSetName)
-                    dependencies.forEach { dependency ->
-                        fragment.declaredModuleDependencies.add(
-                            KotlinModuleDependency(
-                                MavenModuleIdentifier(
-                                    dependency.groupId.orEmpty(),
-                                    dependency.moduleId,
-                                    null /* TODO */
-                                )
+            }
+            metadata.sourceSetModuleDependencies.forEach { (sourceSetName, dependencies) ->
+                val fragment = fragment(sourceSetName)
+                dependencies.forEach { dependency ->
+                    fragment.declaredModuleDependencies.add(
+                        KotlinModuleDependency(
+                            MavenModuleIdentifier(
+                                dependency.groupId.orEmpty(),
+                                dependency.moduleId,
+                                null /* TODO */
                             )
                         )
-                    }
+                    )
                 }
+            }
 
-                metadata.sourceSetsDependsOnRelation.forEach { (depending, dependencies) ->
-                    val dependingFragment = fragment(depending)
-                    dependencies.forEach { dependency ->
-                        dependingFragment.directRefinesDependencies.add(fragment(dependency))
-                    }
+            metadata.sourceSetsDependsOnRelation.forEach { (depending, dependencies) ->
+                val dependingFragment = fragment(depending)
+                dependencies.forEach { dependency ->
+                    dependingFragment.directRefinesDependencies.add(fragment(dependency))
                 }
-            },
-            metadata
+            }
+        }
+        return ExternalImportedKotlinModule(
+            moduleData,
+            metadata,
+            moduleData.fragments.filterTo(mutableSetOf()) { it.fragmentName in metadata.hostSpecificSourceSets }
         )
     }
 
     fun getModule(component: ResolvedComponentResult, projectStructureMetadata: KotlinProjectStructureMetadata): KotlinModule {
-        val moduleId = component.toModuleIdentifier()
+        val moduleId = component.toSingleModuleIdentifier()
         return modulesCache.getOrPut(moduleId) {
             buildModuleFromProjectStructureMetadata(
                 component,

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

@@ -109,13 +109,6 @@ internal object ModuleIds {
     }
 }
 
-interface PublishedModuleCoordinatesProvider {
-    val group: String
-    val name: String
-    val version: String
-    val capabilities: Iterable<String>
-}
-
 open class MavenPublicationCoordinatesProvider(
     project: Project,
     val getPublication: () -> MavenPublication?,

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinCompilationData.kt

@@ -9,38 +9,40 @@ import org.gradle.api.Project
 import org.gradle.api.file.FileCollection
 import org.gradle.api.file.SourceDirectorySet
 import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
-import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
-import org.jetbrains.kotlin.gradle.plugin.KotlinCompilationOutput
-import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
-import org.jetbrains.kotlin.gradle.plugin.LanguageSettingsBuilder
+import org.jetbrains.kotlin.gradle.dsl.pm20Extension
+import org.jetbrains.kotlin.gradle.plugin.*
 import org.jetbrains.kotlin.gradle.plugin.mpp.isMain
+import org.jetbrains.kotlin.gradle.utils.lowerCamelCaseName
+import org.jetbrains.kotlin.project.model.refinesClosure
 
-interface KotlinCompilationData<T : KotlinCommonOptions> {
-    val project: Project
-    val owner: Any?
+interface KotlinVariantCompilationDataInternal<T : KotlinCommonOptions> : KotlinVariantCompilationData<T> {
+    override val compileKotlinTaskName: String
+        get() = lowerCamelCaseName("compile", compilationPurpose.takeIf { it != "main" }, "Kotlin", compilationClassifier)
 
-    val compilationPurpose: String
-    val compilationClassifier: String?
+    override val compileAllTaskName: String
+        get() = owner.disambiguateName("classes")
 
-    val kotlinSourceDirectoriesByFragmentName: Map<String, SourceDirectorySet>
-    val compileKotlinTaskName: String
-    val compileAllTaskName: String
+    override val kotlinSourceDirectoriesByFragmentName: Map<String, SourceDirectorySet>
+        get() = owner.refinesClosure.filterIsInstance<KotlinGradleVariant>().associate { it.disambiguateName("") to it.kotlinSourceRoots }
 
-    val compileDependencyFiles: FileCollection
-    val output: KotlinCompilationOutput
+    override val friendPaths: Iterable<FileCollection>
+        // TODO for now, all output classes of the module are considered friends, even those not on the classpath
+        get() {
+            // FIXME support compiling against the artifact task outputs
+            // TODO note for Android: see the friend artifacts code in KotlinAndroidCompilation
+            return owner.containingModule.project.pm20Extension.modules.flatMap { it.variants.map { it.compilationOutputs.classesDirs } }
+        }
 
-    val languageSettings: LanguageSettingsBuilder
-    val platformType: KotlinPlatformType
+    override val moduleName: String
+        get() = // TODO accurate module names that don't rely on all variants having a main counterpart
+            owner.containingModule.project.pm20Extension.modules
+                .getByName(KotlinGradleModule.MAIN_MODULE_NAME).variants.findByName(owner.name)?.ownModuleName() ?: ownModuleName
 
-    val moduleName: String
-    val ownModuleName: String
-
-    val kotlinOptions: T
-
-    val friendPaths: Iterable<FileCollection>
+    override val ownModuleName: String
+        get() = owner.ownModuleName()
 }
 
-fun KotlinCompilationData<*>.isMain(): Boolean = when (this) {
+fun KotlinCompilationData<*>.isMainCompilationData(): Boolean = when (this) {
     is KotlinCompilation<*> -> isMain()
     else -> compilationPurpose == KotlinGradleModule.MAIN_MODULE_NAME
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinGradleFragment.kt

@@ -6,15 +6,11 @@
 package org.jetbrains.kotlin.gradle.plugin.mpp.pm20
 
 import groovy.lang.Closure
-import org.gradle.api.Named
 import org.gradle.api.NamedDomainObjectProvider
-import org.gradle.api.Project
 import org.gradle.api.file.SourceDirectorySet
 import org.gradle.api.provider.Provider
 import org.gradle.util.ConfigureUtil
-import org.jetbrains.kotlin.gradle.plugin.HasKotlinDependencies
-import org.jetbrains.kotlin.gradle.plugin.KotlinDependencyHandler
-import org.jetbrains.kotlin.gradle.plugin.LanguageSettingsBuilder
+import org.jetbrains.kotlin.gradle.plugin.*
 import org.jetbrains.kotlin.gradle.plugin.mpp.DefaultKotlinDependencyHandler
 import org.jetbrains.kotlin.gradle.plugin.mpp.toModuleDependency
 import org.jetbrains.kotlin.gradle.plugin.sources.DefaultLanguageSettingsBuilder
@@ -25,27 +21,24 @@ import org.jetbrains.kotlin.project.model.KotlinModuleFragment
 import org.jetbrains.kotlin.project.model.refinesClosure
 import javax.inject.Inject
 
-open class KotlinGradleFragment @Inject constructor(
+open class KotlinGradleFragmentInternal @Inject constructor(
     override val containingModule: KotlinGradleModule,
     override val fragmentName: String
-) : KotlinModuleFragment, HasKotlinDependencies, Named {
+) : KotlinGradleFragment {
 
     override fun getName(): String = fragmentName
 
     // TODO pull up to KotlinModuleFragment
     // FIXME apply to compilation
     // FIXME check for consistency
-    val languageSettings: LanguageSettingsBuilder = DefaultLanguageSettingsBuilder()
+    override val languageSettings: LanguageSettingsBuilder = DefaultLanguageSettingsBuilder()
 
-    protected val project: Project
-        get() = containingModule.project
-
-    open fun refines(other: KotlinGradleFragment) {
+    override fun refines(other: KotlinGradleFragment) {
         checkCanRefine(other)
         refines(containingModule.fragments.named(other.name))
     }
 
-    open fun refines(other: NamedDomainObjectProvider<KotlinGradleFragment>) {
+    override fun refines(other: NamedDomainObjectProvider<KotlinGradleFragment>) {
         _directRefinesDependencies.add(other)
         other.configure { checkCanRefine(it) }
         listOf(
@@ -92,23 +85,12 @@ open class KotlinGradleFragment @Inject constructor(
         )
     }
 
-    /** This configuration includes the dependencies from the refines-parents */
-    internal val transitiveApiConfigurationName: String
+    override val transitiveApiConfigurationName: String
         get() = disambiguateName("transitiveApi")
 
-    /** This configuration includes the dependencies from the refines-parents */
-    internal val transitiveImplementationConfigurationName: String
+    override val transitiveImplementationConfigurationName: String
         get() = disambiguateName("transitiveImplementation")
 
-    override val relatedConfigurationNames: List<String>
-        get() = super.relatedConfigurationNames +
-                // TODO: resolvable metadata configurations?
-                listOf(transitiveApiConfigurationName, transitiveImplementationConfigurationName)
-
-    companion object {
-        const val COMMON_FRAGMENT_NAME = "common"
-    }
-
     override fun toString(): String = "fragment $fragmentName in $containingModule"
 }
 

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinGradleModule.kt

@@ -5,25 +5,25 @@
 
 package org.jetbrains.kotlin.gradle.plugin.mpp.pm20
 
-import groovy.lang.Closure
 import org.gradle.api.ExtensiblePolymorphicDomainObjectContainer
-import org.gradle.api.Named
 import org.gradle.api.NamedDomainObjectSet
 import org.gradle.api.Project
-import org.jetbrains.kotlin.gradle.plugin.HasKotlinDependencies
-import org.jetbrains.kotlin.gradle.plugin.KotlinDependencyHandler
 import org.jetbrains.kotlin.gradle.utils.lowerCamelCaseName
-import org.jetbrains.kotlin.project.model.*
+import org.jetbrains.kotlin.project.model.KotlinModuleFragment
+import org.jetbrains.kotlin.project.model.KotlinModuleIdentifier
+import org.jetbrains.kotlin.project.model.LocalModuleIdentifier
 import javax.inject.Inject
 
-open class KotlinGradleModule(
-    internal val project: Project,
-    val moduleClassifier: String?
-) : KotlinModule, Named, HasKotlinDependencies {
+open class KotlinGradleModuleInternal(
+    final override val project: Project,
+    final override val moduleClassifier: String?
+) : KotlinGradleModule {
 
     @Inject
-    constructor(project: Project, moduleClassifier: CharSequence)
-            : this(project, moduleClassifier.toString().takeIf { it != MAIN_MODULE_NAME })
+    constructor(project: Project, moduleName: CharSequence) : this(
+        project,
+        moduleName.takeIf { it != KotlinGradleModule.MAIN_MODULE_NAME }?.toString()
+    )
 
     override val moduleIdentifier: KotlinModuleIdentifier =
         LocalModuleIdentifier(project.currentBuildId().name, project.path, moduleClassifier)
@@ -36,17 +36,17 @@ open class KotlinGradleModule(
         fragments.withType(KotlinGradleVariant::class.java)
     }
 
-    var isPublic: Boolean = false
-        private set
+    override var isPublic: Boolean = false
+        protected set
 
     private var setPublicHandlers: MutableList<() -> Unit> = mutableListOf()
 
-    fun ifMadePublic(action: () -> Unit) {
+    override fun ifMadePublic(action: () -> Unit) {
         // FIXME reentrancy?
         if (isPublic) action() else setPublicHandlers.add(action)
     }
 
-    fun makePublic() {
+    override fun makePublic() {
         if (isPublic) return
         setPublicHandlers.forEach { it() }
         isPublic = true
@@ -57,37 +57,6 @@ open class KotlinGradleModule(
         const val TEST_MODULE_NAME = "test"
     }
 
-    override fun getName(): String = when (moduleClassifier) {
-        null -> MAIN_MODULE_NAME
-        else -> moduleClassifier
-    }
-
-    // DSL
-
-    val common: KotlinGradleFragment
-        get() = fragments.getByName(KotlinGradleFragment.COMMON_FRAGMENT_NAME)
-
-    fun common(configure: KotlinGradleFragment.() -> Unit) =
-        common.configure()
-
-    override fun dependencies(configure: KotlinDependencyHandler.() -> Unit) =
-        common.dependencies(configure)
-
-    override fun dependencies(configureClosure: Closure<Any?>) =
-        common.dependencies(configureClosure)
-
-    override val apiConfigurationName: String
-        get() = common.apiConfigurationName
-
-    override val implementationConfigurationName: String
-        get() = common.implementationConfigurationName
-
-    override val compileOnlyConfigurationName: String
-        get() = common.compileOnlyConfigurationName
-
-    override val runtimeOnlyConfigurationName: String
-        get() = common.runtimeOnlyConfigurationName
-
     override fun toString(): String = "$moduleIdentifier (Gradle)"
 }
 

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinGradleModuleFactory.kt

@@ -11,7 +11,7 @@ import org.jetbrains.kotlin.gradle.dsl.pm20Extension
 
 open class KotlinGradleModuleFactory(private val project: Project) : NamedDomainObjectFactory<KotlinGradleModule> {
     override fun create(name: String): KotlinGradleModule {
-        val result = project.objects.newInstance(KotlinGradleModule::class.java, project, name)
+        val result = project.objects.newInstance(KotlinGradleModuleInternal::class.java, project, name)
         registerFragmentFactory(result)
         registerDefaultCommonFragment(result)
         addDefaultDependencyOnMainModule(result)

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinJvmVariant.kt

@@ -26,9 +26,7 @@ open class KotlinJvmVariant(containingModule: KotlinGradleModule, fragmentName:
         get() = KotlinPlatformType.jvm
 }
 
-class KotlinJvmVariantCompilationData(val variant: KotlinJvmVariant) : KotlinCompilationData<KotlinJvmOptions> {
-    override val project: Project get() = variant.containingModule.project
-
+class KotlinJvmVariantCompilationData(val variant: KotlinJvmVariant) : KotlinVariantCompilationDataInternal<KotlinJvmOptions> {
     override val owner: KotlinJvmVariant get() = variant
 
     override val compilationPurpose: String

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinNativeVariantFactory.kt

@@ -0,0 +1,173 @@
+/*
+ * Copyright 2010-2021 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.
+ */
+
+package org.jetbrains.kotlin.gradle.plugin.mpp.pm20
+
+import org.gradle.api.artifacts.Configuration
+import org.gradle.api.artifacts.Dependency
+import org.gradle.api.artifacts.ModuleDependency
+import org.gradle.api.attributes.Usage
+import org.gradle.api.component.AdhocComponentWithVariants
+import org.gradle.api.component.SoftwareComponentFactory
+import org.gradle.api.internal.project.ProjectInternal
+import org.gradle.api.publish.PublishingExtension
+import org.gradle.api.publish.maven.MavenPublication
+import org.gradle.api.publish.maven.internal.publication.DefaultMavenPublication
+import org.gradle.jvm.tasks.Jar
+import org.jetbrains.kotlin.gradle.dsl.pm20Extension
+import org.jetbrains.kotlin.gradle.plugin.KotlinNativeTargetConfigurator
+import org.jetbrains.kotlin.gradle.plugin.getKotlinPluginVersion
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTarget
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinUsages
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.util.CalculatedCapability
+import org.jetbrains.kotlin.gradle.plugin.mpp.publishedConfigurationName
+import org.jetbrains.kotlin.gradle.plugin.usageByName
+import org.jetbrains.kotlin.gradle.targets.metadata.filesWithUnpackedArchives
+import org.jetbrains.kotlin.gradle.tasks.registerTask
+import org.jetbrains.kotlin.gradle.utils.dashSeparatedName
+import org.jetbrains.kotlin.library.KLIB_FILE_EXTENSION
+import org.jetbrains.kotlin.project.model.refinesClosure
+import org.jetbrains.kotlin.project.model.utils.variantsContainingFragment
+import kotlin.reflect.KClass
+
+open class KotlinNativeVariantFactory<T : KotlinNativeVariantInternal>(
+    module: KotlinGradleModule,
+    val variantClass: KClass<out T>
+) :
+    AbstractKotlinGradleVariantFactory<T>(module) {
+
+    override fun instantiateFragment(name: String): T =
+        module.project.objects.newInstance(variantClass.java, module, name)
+
+    override fun setPlatformAttributesInConfiguration(fragment: T, configuration: Configuration) {
+        super.setPlatformAttributesInConfiguration(fragment, configuration)
+        configuration.attributes.attribute(KotlinNativeTarget.konanTargetAttribute, fragment.konanTarget.name)
+    }
+
+    override fun create(name: String): T =
+        super.create(name).also { result ->
+            configureVariantPublishing(result)
+        }
+
+    override fun configureKotlinCompilation(fragment: T) {
+        val compilationData = fragment.compilationData
+
+        //FIXME: deduplicate with KotlinJvmVariantFactory
+        val classesTaskName = compilationData.compileAllTaskName
+        project.tasks.register(classesTaskName) { classesTask ->
+            classesTask.dependsOn(fragment.compilationOutputs.allOutputs)
+        }
+
+        //FIXME: needs refactoring so as not to create the configurator
+        val compileTask = with(KotlinNativeTargetConfigurator<Nothing>(project.getKotlinPluginVersion()!!)) {
+            project.createKlibCompilationTask(compilationData)
+        }
+
+        // FIXME: duplication with KotlinJvmVariantFactory
+        val allSources = { project.files(Callable { fragment.refinesClosure.map { it.kotlinSourceRoots } }) }
+        val commonSources = {
+            project.files(Callable {
+                fragment.refinesClosure.filter { module.variantsContainingFragment(it).count() > 1 }.map { it.kotlinSourceRoots }
+            })
+        }
+
+        compileTask.configure {
+            it.source(allSources)
+            it.commonSources.from(commonSources)
+        }
+    }
+
+    open fun configureVariantPublishing(variant: T) {
+        val rootSoftwareComponent =
+            project.components
+                .withType(AdhocComponentWithVariants::class.java)
+                .getByName(rootPublicationComponentName(module))
+
+        val platformModuleDependencyProvider = project.provider {
+            val coordinates = variant.publishedMavenModuleCoordinates
+            (project.dependencies.create("${coordinates.group}:${coordinates.name}:${coordinates.version}") as ModuleDependency).apply {
+                if (module.moduleClassifier != null) {
+                    capabilities { it.requireCapability(CalculatedCapability.fromModule(module)) }
+                }
+            }
+        }
+
+        val apiElements = project.configurations.getByName(variant.apiElementsConfigurationName)
+        val hostSpecificMetadataJar = project.registerTask<Jar>(variant.disambiguateName("hostSpecificMetadataJar")) { jar ->
+            jar.archiveClassifier.set("metadata")
+            jar.archiveAppendix.set(variant.disambiguateName(""))
+            project.pm20Extension.metadataCompilationRegistryByModuleId.getValue(variant.containingModule.moduleIdentifier)
+                .withAll { metadataCompilation ->
+                    val fragment = metadataCompilation.fragment
+                    if (metadataCompilation is KotlinNativeFragmentMetadataCompilationData) {
+                        jar.from(project.files(Callable {
+                            if (fragment in variant.refinesClosure && fragment.isNativeHostSpecific())
+                                project.filesWithUnpackedArchives(metadataCompilation.output.allOutputs, setOf(KLIB_FILE_EXTENSION))
+                            else emptyList<Any>()
+                        })) { spec -> spec.into(fragment.name) }
+                    }
+                }
+        }
+        val hostSpecificMetadataElements = project.configurations.create(variant.hostSpecificMetadataConfigurationName).apply {
+            isCanBeResolved = false
+            isCanBeConsumed = false
+            setPlatformAttributesAndMetadataUsage(variant)
+            project.artifacts.add(name, hostSpecificMetadataJar)
+            dependencies.addAllLater(project.objects.listProperty(Dependency::class.java).apply {
+                set(project.provider { apiElements.allDependencies })
+            })
+        }
+
+        // FIXME inject vs internal API
+        val platformComponentName = platformComponentName(variant)
+        val platformComponent = (project as ProjectInternal).services
+            .get(SoftwareComponentFactory::class.java)
+            .adhoc(platformComponentName)
+        project.components.add(platformComponent)
+        platformComponent.addVariantsFromConfiguration(apiElements) {
+            it.mapToMavenScope("compile")
+        }
+        platformComponent.addVariantsFromConfiguration(hostSpecificMetadataElements) { }
+
+        module.ifMadePublic {
+            project.pluginManager.withPlugin("maven-publish") {
+                project.extensions.getByType(PublishingExtension::class.java).apply {
+                    publications.create(platformComponentName, MavenPublication::class.java).apply {
+                        (this as DefaultMavenPublication).isAlias = true
+                        from(platformComponent)
+                        variant.assignMavenPublication(this)
+                        artifactId = dashSeparatedName(project.name, variant.defaultPublishedModuleSuffix)
+                    }
+                }
+            }
+        }
+
+        val publishedApiConfiguration =
+            project.configurations.create(publishedConfigurationName(variant.apiElementsConfigurationName)).apply {
+                isCanBeConsumed = false
+                isCanBeResolved = false
+                configureApiElementsConfiguration(variant, this)
+                setModuleCapability(this, module)
+                dependencies.addLater(platformModuleDependencyProvider)
+            }
+        val publishedMetadataConfiguration =
+            project.configurations.create(publishedConfigurationName(variant.hostSpecificMetadataConfigurationName)).apply {
+                isCanBeConsumed = false
+                isCanBeResolved = false
+                setPlatformAttributesAndMetadataUsage(variant)
+                setModuleCapability(this, module)
+                dependencies.addLater(platformModuleDependencyProvider)
+            }
+        rootSoftwareComponent.addVariantsFromConfiguration(publishedApiConfiguration) { }
+        rootSoftwareComponent.addVariantsFromConfiguration(publishedMetadataConfiguration) { }
+    }
+
+    private fun Configuration.setPlatformAttributesAndMetadataUsage(variant: T) {
+        configureApiElementsConfiguration(variant, this) // then override the Usage attribute
+        attributes.attribute(Usage.USAGE_ATTRIBUTE, project.usageByName(KotlinUsages.KOTLIN_METADATA))
+    }
+
+    open fun platformComponentName(variant: T) = variant.disambiguateName("")
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/abstractVariants.kt

@@ -5,66 +5,58 @@
 
 package org.jetbrains.kotlin.gradle.plugin.mpp.pm20
 
+import org.gradle.api.Project
+import org.gradle.api.artifacts.Configuration
 import org.gradle.api.file.ConfigurableFileCollection
 import org.gradle.api.file.FileCollection
 import org.gradle.api.publish.maven.MavenPublication
 import org.gradle.api.tasks.TaskProvider
 import org.gradle.api.tasks.bundling.AbstractArchiveTask
-import org.jetbrains.kotlin.gradle.plugin.KotlinCompilationOutput
-import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
+import org.jetbrains.kotlin.gradle.plugin.*
 import org.jetbrains.kotlin.gradle.plugin.mpp.DefaultKotlinCompilationOutput
 import org.jetbrains.kotlin.gradle.plugin.mpp.MavenPublicationCoordinatesProvider
-import org.jetbrains.kotlin.gradle.plugin.mpp.PublishedModuleCoordinatesProvider
 import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.util.CalculatedCapability
 import org.jetbrains.kotlin.gradle.plugin.mpp.publishedConfigurationName
 import org.jetbrains.kotlin.gradle.tasks.withType
 import org.jetbrains.kotlin.gradle.utils.dashSeparatedName
 import org.jetbrains.kotlin.project.model.KotlinAttributeKey
-import org.jetbrains.kotlin.project.model.KotlinModuleVariant
 import org.jetbrains.kotlin.project.model.KotlinPlatformTypeAttribute
 
-abstract class KotlinGradleVariant(
+abstract class KotlinGradleVariantInternal(
     containingModule: KotlinGradleModule,
     override val fragmentName: String
-) : KotlinGradleFragment(containingModule, fragmentName), KotlinModuleVariant {
+) : KotlinGradleFragmentInternal(containingModule, fragmentName), KotlinGradleVariant {
 
-    abstract val platformType: KotlinPlatformType
+    final override val project: Project // overriding with final to avoid warnings
+        get() = super<KotlinGradleFragmentInternal>.project
 
     override val variantAttributes: Map<KotlinAttributeKey, String>
         get() = mapOf(KotlinPlatformTypeAttribute to kotlinPlatformTypeAttributeFromPlatform(platformType)) // TODO user attributes
 
     // TODO generalize with KotlinCompilation?
-    val compileDependencyConfigurationName: String
+    override val compileDependencyConfigurationName: String
         get() = disambiguateName("CompileDependencies")
 
-    open lateinit var compileDependencyFiles: FileCollection
+    override lateinit var compileDependencyFiles: FileCollection
 
     // TODO rewrite using our own artifacts API?
-    val compilationOutputs: KotlinCompilationOutput =
+    override val compilationOutputs: KotlinCompilationOutput =
         DefaultKotlinCompilationOutput(
             project,
             project.provider { project.buildDir.resolve("processedResources/${containingModule.name}/${fragmentName}") }
         )
 
     // TODO rewrite using our own artifacts API
-    open val sourceArchiveTask: TaskProvider<AbstractArchiveTask>
+    override val sourceArchiveTask: TaskProvider<AbstractArchiveTask>
         get() = project.tasks.withType<AbstractArchiveTask>().named(defaultSourceArtifactTaskName)
 
     // TODO generalize exposing outputs: what if a variant has more than one such configurations or none?
-    val apiElementsConfigurationName: String
+    override val apiElementsConfigurationName: String
         get() = disambiguateName("apiElements")
 
-    abstract val gradleVariantNames: Set<String>
-
     override fun toString(): String = "variant $fragmentName in $containingModule"
 }
 
-interface SingleMavenPublicationHolder {
-    fun assignMavenPublication(publication: MavenPublication)
-    val defaultPublishedModuleSuffix: String?
-    val publishedMavenModuleCoordinates: PublishedModuleCoordinatesProvider
-}
-
 class DefaultSingleMavenPublicationHolder(
     private var module: KotlinGradleModule,
     override val defaultPublishedModuleSuffix: String?
@@ -94,22 +86,23 @@ private fun kotlinPlatformTypeAttributeFromPlatform(platformType: KotlinPlatform
 internal val KotlinGradleVariant.defaultSourceArtifactTaskName: String
     get() = disambiguateName("sourcesJar")
 
-abstract class KotlinGradleVariantWithRuntime(
+abstract class KotlinGradleVariantWithRuntimeInternal(
     containingModule: KotlinGradleModule,
     fragmentName: String
-) : KotlinGradleVariant(containingModule, fragmentName) {
+) : KotlinGradleVariantInternal(containingModule, fragmentName), KotlinGradleVariantWithRuntime {
     // TODO deduplicate with KotlinCompilation?
-    val runtimeDependencyConfigurationName: String
+    override val runtimeDependencyConfigurationName: String
         get() = disambiguateName("RuntimeDependencies")
 
-    open lateinit var runtimeDependencyFiles: FileCollection
+    override lateinit var runtimeDependencyFiles: FileCollection
 
-    open val runtimeFiles: ConfigurableFileCollection by lazy {
-        project.files(compilationOutputs.allOutputs, runtimeDependencyFiles)
-    }
+    override val runtimeFiles: ConfigurableFileCollection = project.files(
+        { compilationOutputs.allOutputs },
+        { runtimeDependencyFiles }
+    )
 
     // TODO generalize exposing outputs: what if a variant has more than one such configurations or none?
-    val runtimeElementsConfigurationName: String
+    override val runtimeElementsConfigurationName: String
         get() = disambiguateName("runtimeElements")
 }
 
@@ -117,7 +110,7 @@ private fun defaultModuleSuffix(module: KotlinGradleModule, variantName: String)
     dashSeparatedName(variantName, module.moduleClassifier)
 
 abstract class KotlinGradlePublishedVariantWithRuntime(containingModule: KotlinGradleModule, fragmentName: String) :
-    KotlinGradleVariantWithRuntime(containingModule, fragmentName),
+    KotlinGradleVariantWithRuntimeInternal(containingModule, fragmentName),
     SingleMavenPublicationHolder by DefaultSingleMavenPublicationHolder(
         containingModule,
         defaultModuleSuffix(containingModule, fragmentName)

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/fragmentFactories.kt

@@ -60,7 +60,7 @@ abstract class AbstractKotlinGradleFragmentFactory<T : KotlinGradleFragment>(
     }
 }
 
-class CommonGradleFragmentFactory(module: KotlinGradleModule) : AbstractKotlinGradleFragmentFactory<KotlinGradleFragment>(module) {
-    override fun instantiateFragment(name: String): KotlinGradleFragment =
-        project.objects.newInstance(KotlinGradleFragment::class.java, module, name)
+class CommonGradleFragmentFactory(module: KotlinGradleModule) : AbstractKotlinGradleFragmentFactory<KotlinGradleFragmentInternal>(module) {
+    override fun instantiateFragment(name: String): KotlinGradleFragmentInternal =
+        project.objects.newInstance(KotlinGradleFragmentInternal::class.java, module, name)
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/fragmentsMetadataCompilation.kt

@@ -12,12 +12,12 @@ import org.gradle.api.tasks.TaskProvider
 import org.gradle.jvm.tasks.Jar
 import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformCommonOptions
 import org.jetbrains.kotlin.gradle.dsl.pm20Extension
+import org.jetbrains.kotlin.gradle.plugin.*
 import org.jetbrains.kotlin.gradle.plugin.KotlinCommonSourceSetProcessor
-import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
-import org.jetbrains.kotlin.gradle.plugin.getKotlinPluginVersion
 import org.jetbrains.kotlin.gradle.plugin.mpp.*
-import org.jetbrains.kotlin.gradle.plugin.usageByName
+import org.jetbrains.kotlin.gradle.targets.metadata.NativeSharedCompilationProcessor
 import org.jetbrains.kotlin.gradle.targets.metadata.createGenerateProjectStructureMetadataTask
+import org.jetbrains.kotlin.gradle.targets.metadata.filesWithUnpackedArchives
 import org.jetbrains.kotlin.gradle.tasks.KotlinTasksProvider
 import org.jetbrains.kotlin.gradle.tasks.registerTask
 import org.jetbrains.kotlin.gradle.tasks.withType
@@ -124,10 +124,14 @@ private fun configureMetadataJarTask(
         task.archiveAppendix.set("metadata")
         task.from()
     }
-    registry.withAll { compilationData ->
+    module.fragments.all { fragment ->
         allMetadataJar.configure { jar ->
-            jar.from(compilationData.output.allOutputs) { spec ->
-                spec.into(compilationData.fragment.fragmentName)
+            val metadataOutput = project.files(Callable {
+                val compilationData = registry.byFragment(fragment)
+                project.filesWithUnpackedArchives(compilationData.output.allOutputs, setOf(KLIB_FILE_EXTENSION))
+            })
+            jar.from(metadataOutput) { spec ->
+                spec.into(fragment.fragmentName)
             }
         }
     }