[KPM] Implement initial IdeaKotlinProjectModelBuilder

- Introduce `kotlin-gradle-plugin-idea` module that allows
to share models between the IDE and KGP

- Add `kotlin-gradle-plugin-idea` to the RuntimePublicAPITest to
ensure binary compatibility

^KT-51262

.idea/kotlinScripting.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="KotlinScriptingSettings">
+    <option name="suppressDefinitionsCheck" value="true" />
+  </component>
+</project>

build.gradle.kts

@@ -362,6 +362,7 @@ val projectsWithDisabledFirBootstrap = coreLibProjects + listOf(
 val gradlePluginProjects = listOf(
     ":kotlin-gradle-plugin",
     ":kotlin-gradle-plugin-api",
+    ":kotlin-gradle-plugin-idea",
     ":kotlin-gradle-plugin-kpm-android",
     ":kotlin-allopen",
     ":kotlin-annotation-processing-gradle",

buildSrc/src/main/kotlin/tasks.kt

@@ -40,6 +40,7 @@ val kotlinGradlePluginAndItsRequired = arrayOf(
     ":kotlin-daemon-client",
     ":kotlin-project-model",
     ":kotlin-gradle-plugin-api",
+    ":kotlin-gradle-plugin-idea",
     ":kotlin-gradle-plugin",
     ":kotlin-gradle-plugin-model",
     ":kotlin-tooling-metadata",

libraries/tools/binary-compatibility-validator/ReadMe.md

@@ -7,7 +7,7 @@ and ensure that the public binary API wasn't changed in a way that make this cha
 
 Compile and run tests. `CasesPublicAPITest` verifies the tool itself, 
 and `RuntimePublicAPITest` dumps the public API of `kotlin-stdlib`, 
-`kotlin-stdlib-jdk7/8`, and `kotlin-reflect` jars,
+`kotlin-stdlib-jdk7/8`, `kotlin-reflect` and `kotlin-gradle-plugin-idea` jars,
 which must be built beforehand with gradle. Use `clean assemble` tasks,
 since the incremental compilation currently doesn't produce all the required output.
 

libraries/tools/binary-compatibility-validator/build.gradle

@@ -14,6 +14,7 @@ dependencies {
     testArtifacts project(':kotlin-stdlib-jdk7')
     testArtifacts project(':kotlin-stdlib-jdk8')
     testArtifacts project(':kotlin-reflect')
+    testArtifacts project(':kotlin-gradle-plugin-idea')
 }
 
 pill {

libraries/tools/binary-compatibility-validator/src/test/kotlin/org.jetbrains.kotlin.tools.tests/RuntimePublicAPITest.kt

@@ -33,6 +33,10 @@ class RuntimePublicAPITest {
         snapshotAPIAndCompare("../../reflect/api/build/libs", "kotlin-reflect-api(?!-[-a-z]+)", nonPublicPackages = listOf("kotlin.reflect.jvm.internal"))
     }
 
+    @Test fun kotlinGradlePluginIdea() {
+        snapshotAPIAndCompare("../kotlin-gradle-plugin-idea/build/libs", "kotlin-gradle-plugin-idea(?!-[-a-z]+)")
+    }
+
     private fun snapshotAPIAndCompare(
         basePath: String,
         jarPattern: String,

libraries/tools/kotlin-gradle-plugin-api/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/kotlinTopLevelExtensionConfig.kt

@@ -40,7 +40,7 @@ interface ExperimentalExtensionConfig {
 /**
  * Different modes that can be used to set the level of issue reporting for [KotlinTopLevelExtensionConfig.explicitApi] option.
  */
-enum class ExplicitApiMode(private val cliOption: String) {
+enum class ExplicitApiMode(val cliOption: String) {
     /** Report issues as errors. */
     Strict("strict"),
 

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

@@ -31,6 +31,8 @@ interface KotlinGradleFragment : KotlinModuleFragment, HasKotlinDependencies, Ko
 
     fun refines(other: NamedDomainObjectProvider<KotlinGradleFragment>)
 
+    override val directRefinesDependencies: Iterable<KotlinGradleFragment>
+
     override fun dependencies(configureClosure: Closure<Any?>) =
         dependencies f@{ project.configure(this@f, configureClosure) }
 

libraries/tools/kotlin-gradle-plugin-idea/ReadMe.md

@@ -0,0 +1,13 @@
+# Kotlin Gradle Plugin Models shared between IDEA import and KGP
+The classes defined in this module will be available inside the Kotlin Gradle Plugin (KGP) 
+as well as in the IDE import (GradleProject).
+
+## Binary Compatibility: 
+Binary compatibility can be tested by
+`./gradlew :tools:binary-compatibility-validator:clean :tools:binary-compatibility-validator:test`
+
+Binary incompatible changes have to go through a proper deprecation cycle after releases
+
+### Unstable APIs / KotlinGradlePluginApi
+Some APIs are marked with 'KotlinGradlePluginApi' which means, that those are not kept binary compatible and are considered 'unstable'
+from the IDEA perspective. Typically constructors for models are marked like this

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

@@ -0,0 +1,9 @@
+plugins {
+    kotlin("jvm")
+}
+
+dependencies {
+    implementation(project(":kotlin-stdlib"))
+}
+
+publish()

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinFragment.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+import java.io.Serializable
+
+interface IdeaKotlinFragment : Serializable {
+    val name: String
+    val languageSettings: IdeaKotlinLanguageSettings?
+    val dependencies: Collection<IdeaKotlinFragmentDependency>
+    val directRefinesDependencies: Collection<IdeaKotlinFragment>
+    val sourceDirectories: Collection<IdeaKotlinSourceDirectory>
+    val resourceDirectories: Collection<IdeaKotlinResourceDirectory>
+}
+
+class IdeaKotlinFragmentImpl @KotlinGradlePluginApi constructor(
+    override val name: String,
+    override val languageSettings: IdeaKotlinLanguageSettings?,
+    override val dependencies: Collection<IdeaKotlinFragmentDependency>,
+    override val directRefinesDependencies: Collection<IdeaKotlinFragment>,
+    override val sourceDirectories: Collection<IdeaKotlinSourceDirectory>,
+    override val resourceDirectories: Collection<IdeaKotlinResourceDirectory>
+) : IdeaKotlinFragment
+
+

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinFragmentDependency.kt

@@ -0,0 +1,8 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+interface IdeaKotlinFragmentDependency

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinLanguageSettings.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+import java.io.File
+
+interface IdeaKotlinLanguageSettings {
+    val languageVersion: String?
+    val apiVersion: String?
+    val isProgressiveMode: Boolean
+    val enabledLanguageFeatures: Collection<String>
+    val optInAnnotationsInUse: Collection<String>
+    val compilerPluginArguments: Collection<String>
+    val compilerPluginClasspath: Collection<File>
+    val freeCompilerArgs: Collection<String>
+}
+
+class IdeaKotlinLanguageSettingsImpl @KotlinGradlePluginApi constructor(
+    override val languageVersion: String?,
+    override val apiVersion: String?,
+    override val isProgressiveMode: Boolean,
+    override val enabledLanguageFeatures: Collection<String>,
+    override val optInAnnotationsInUse: Collection<String>,
+    override val compilerPluginArguments: Collection<String>,
+    override val compilerPluginClasspath: Collection<File>,
+    override val freeCompilerArgs: Collection<String>
+) : IdeaKotlinLanguageSettings

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinModule.kt

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+import java.io.Serializable
+
+interface IdeaKotlinModule : Serializable {
+    val moduleIdentifier: IdeaKotlinModuleIdentifier
+    val fragments: Collection<IdeaKotlinFragment>
+}
+
+class IdeaKotlinModuleImpl @KotlinGradlePluginApi constructor(
+    override val moduleIdentifier: IdeaKotlinModuleIdentifier,
+    override val fragments: Collection<IdeaKotlinFragment>
+) : IdeaKotlinModule

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinModuleIdentifier.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+import java.io.Serializable
+
+sealed interface IdeaKotlinModuleIdentifier : Serializable {
+    val moduleClassifier: String?
+}
+
+interface IdeaKotlinLocalModuleIdentifier : IdeaKotlinModuleIdentifier {
+    val buildId: String
+    val projectId: String
+}
+
+interface IdeaKotlinMavenModuleIdentifier : IdeaKotlinModuleIdentifier {
+    val group: String
+    val name: String
+}
+
+class IdeaKotlinLocalModuleIdentifierImpl @KotlinGradlePluginApi constructor(
+    override val moduleClassifier: String?,
+    override val buildId: String,
+    override val projectId: String
+) : IdeaKotlinLocalModuleIdentifier
+
+class IdeaKotlinMavenModuleIdentifierImpl @KotlinGradlePluginApi constructor(
+    override val moduleClassifier: String?,
+    override val group: String,
+    override val name: String
+) : IdeaKotlinMavenModuleIdentifier

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinProjectModel.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+import java.io.File
+import java.io.Serializable
+
+interface IdeaKotlinProjectModel : Serializable {
+    val coreLibrariesVersion: String
+    val explicitApiModeCliOption: String?
+    val kotlinNativeHome: File
+    val modules: List<IdeaKotlinModule>
+}
+
+class IdeaKotlinProjectModelImpl @KotlinGradlePluginApi constructor(
+    override val coreLibrariesVersion: String,
+    override val explicitApiModeCliOption: String?,
+    override val kotlinNativeHome: File,
+    override val modules: List<IdeaKotlinModule>
+) : IdeaKotlinProjectModel

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinResourceDirectory.kt

@@ -0,0 +1,17 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+import java.io.File
+import java.io.Serializable
+
+interface IdeaKotlinResourceDirectory : Serializable {
+    val file: File
+}
+
+class IdeaKotlinResourceDirectoryImpl @KotlinGradlePluginApi constructor(
+    override val file: File
+) : IdeaKotlinResourceDirectory

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinSourceDirectory.kt

@@ -0,0 +1,17 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+import java.io.File
+import java.io.Serializable
+
+interface IdeaKotlinSourceDirectory : Serializable {
+    val file: File
+}
+
+class IdeaKotlinSourceDirectoryImpl @KotlinGradlePluginApi constructor(
+    override val file: File,
+) : IdeaKotlinSourceDirectory

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/KotlinGradlePluginApi.kt

@@ -0,0 +1,12 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+@RequiresOptIn(
+    level = RequiresOptIn.Level.ERROR,
+    message = "This API can only be used by the Kotlin Gradle Plugin and is not kept stable for access inside the IDE process"
+)
+annotation class KotlinGradlePluginApi

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

@@ -30,6 +30,7 @@ kotlin.sourceSets.all {
     languageSettings.optIn("kotlin.RequiresOptIn")
     languageSettings.optIn("org.jetbrains.kotlin.gradle.plugin.mpp.external.ExternalVariantApi")
     languageSettings.optIn("org.jetbrains.kotlin.gradle.plugin.mpp.external.AdvancedExternalVariantApi")
+    languageSettings.optIn("org.jetbrains.kotlin.gradle.kpm.idea.KotlinGradlePluginApi")
 }
 
 dependencies {
@@ -56,6 +57,7 @@ dependencies {
     embedded(project(":kotlin-gradle-statistics"))
     compileOnly(project(":kotlin-gradle-build-metrics"))
     embedded(project(":kotlin-gradle-build-metrics"))
+    implementation(project(":kotlin-gradle-plugin-idea"))
 
     implementation(commonDependency("com.google.code.gson:gson"))
     implementation(commonDependency("com.google.guava:guava"))

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinFragmentBuilder.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinGradleFragment
+
+internal fun KotlinGradleFragment.toIdeaKotlinFragment(
+    cache: MutableMap<KotlinGradleFragment, IdeaKotlinFragment> = mutableMapOf()
+): IdeaKotlinFragment {
+    return cache.getOrPut(this) {
+        IdeaKotlinFragmentImpl(
+            name = name,
+            languageSettings = languageSettings.toIdeaKotlinLanguageSettings(),
+            dependencies = emptyList(),
+            directRefinesDependencies = directRefinesDependencies.map { refinesFragment ->
+                refinesFragment.toIdeaKotlinFragment(cache)
+            },
+            sourceDirectories = kotlinSourceRoots.sourceDirectories.files.toList().map { file ->
+                IdeaKotlinSourceDirectoryImpl(file)
+            },
+            resourceDirectories = emptyList()
+        )
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinLanguageSettingsBuilder.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+import org.jetbrains.kotlin.gradle.plugin.sources.DefaultLanguageSettingsBuilder
+import org.jetbrains.kotlin.project.model.LanguageSettings
+
+internal fun LanguageSettings.toIdeaKotlinLanguageSettings(): IdeaKotlinLanguageSettings {
+    return IdeaKotlinLanguageSettingsImpl(
+        languageVersion = languageVersion,
+        apiVersion = apiVersion,
+        isProgressiveMode = progressiveMode,
+        enabledLanguageFeatures = enabledLanguageFeatures.toSet(),
+        optInAnnotationsInUse = optInAnnotationsInUse.toSet(),
+        compilerPluginArguments = (this as? DefaultLanguageSettingsBuilder)?.compilerPluginArguments?.toList().orEmpty(),
+        compilerPluginClasspath = (this as? DefaultLanguageSettingsBuilder)?.compilerPluginClasspath?.toList().orEmpty(),
+        freeCompilerArgs = (this as? DefaultLanguageSettingsBuilder)?.freeCompilerArgs?.toList().orEmpty()
+    )
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinModuleBuilder.kt

@@ -0,0 +1,17 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinGradleFragment
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinGradleModule
+
+internal fun KotlinGradleModule.toIdeaKotlinModule(): IdeaKotlinModule {
+    val fragmentsCache = mutableMapOf<KotlinGradleFragment, IdeaKotlinFragment>()
+    return IdeaKotlinModuleImpl(
+        moduleIdentifier = moduleIdentifier.toIdeaKotlinModuleIdentifier(),
+        fragments = fragments.toList().map { fragment -> fragment.toIdeaKotlinFragment(fragmentsCache) }
+    )
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinModuleIdentifierBuilder.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2010-2022 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.kpm.idea
+
+import org.jetbrains.kotlin.project.model.KotlinModuleIdentifier
+import org.jetbrains.kotlin.project.model.LocalModuleIdentifier
+import org.jetbrains.kotlin.project.model.MavenModuleIdentifier
+
+internal fun KotlinModuleIdentifier.toIdeaKotlinModuleIdentifier(): IdeaKotlinModuleIdentifier {
+    return when (this) {
+        is LocalModuleIdentifier -> IdeaKotlinLocalModuleIdentifierImpl(
+            moduleClassifier, buildId = buildId, projectId = projectId
+        )
+        is MavenModuleIdentifier -> IdeaKotlinMavenModuleIdentifierImpl(
+            moduleClassifier, group = group, name = name
+        )
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinProjectModelBuilder.kt

@@ -0,0 +1,24 @@
+package org.jetbrains.kotlin.gradle.kpm.idea
+
+import org.gradle.api.Project
+import org.gradle.tooling.provider.model.ToolingModelBuilder
+import org.jetbrains.kotlin.compilerRunner.konanHome
+import org.jetbrains.kotlin.gradle.dsl.pm20Extension
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinPm20ProjectExtension
+import java.io.File
+
+class IdeaKotlinProjectModelBuilder : ToolingModelBuilder {
+    override fun canBuild(modelName: String): Boolean = modelName == IdeaKotlinProjectModel::class.java.name
+    override fun buildAll(modelName: String, project: Project): IdeaKotlinProjectModel {
+        return project.pm20Extension.toIdeaKotlinProjectModel()
+    }
+}
+
+internal fun KotlinPm20ProjectExtension.toIdeaKotlinProjectModel(): IdeaKotlinProjectModel {
+    return IdeaKotlinProjectModelImpl(
+        coreLibrariesVersion = coreLibrariesVersion,
+        explicitApiModeCliOption = explicitApi?.cliOption,
+        kotlinNativeHome = File(project.konanHome).absoluteFile,
+        modules = modules.map { module -> module.toIdeaKotlinModule() }
+    )
+}

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

@@ -13,18 +13,21 @@ import org.gradle.api.component.SoftwareComponentFactory
 import org.gradle.api.plugins.JavaBasePlugin
 import org.gradle.api.publish.PublishingExtension
 import org.gradle.api.publish.maven.MavenPublication
+import org.gradle.tooling.provider.model.ToolingModelBuilderRegistry
 import org.gradle.util.GradleVersion
 import org.jetbrains.kotlin.gradle.dsl.KotlinProjectExtension
 import org.jetbrains.kotlin.gradle.dsl.KotlinTopLevelExtension
 import org.jetbrains.kotlin.gradle.dsl.pm20Extension
 import org.jetbrains.kotlin.gradle.dsl.topLevelExtensionOrNull
 import org.jetbrains.kotlin.gradle.internal.customizeKotlinDependencies
+import org.jetbrains.kotlin.gradle.kpm.idea.IdeaKotlinProjectModelBuilder
 import org.jetbrains.kotlin.gradle.utils.checkGradleCompatibility
 import org.jetbrains.kotlin.project.model.KotlinModuleIdentifier
 import javax.inject.Inject
 
 abstract class KotlinPm20GradlePlugin @Inject constructor(
-    @Inject private val softwareComponentFactory: SoftwareComponentFactory
+    @Inject private val softwareComponentFactory: SoftwareComponentFactory,
+    @Inject private val toolingModelBuilderRegistry: ToolingModelBuilderRegistry
 ) : Plugin<Project> {
     override fun apply(project: Project) {
         checkGradleCompatibility("the Kotlin Multiplatform plugin", GradleVersion.version("6.1"))
@@ -37,6 +40,7 @@ abstract class KotlinPm20GradlePlugin @Inject constructor(
         registerDefaultVariantFactories(project)
         setupFragmentsMetadataForKpmModules(project)
         setupKpmModulesPublication(project)
+        setupToolingModelBuilder()
     }
 
     private fun createDefaultModules(project: Project) {
@@ -77,6 +81,10 @@ abstract class KotlinPm20GradlePlugin @Inject constructor(
             }
         }
     }
+
+    private fun setupToolingModelBuilder() {
+        toolingModelBuilderRegistry.register(IdeaKotlinProjectModelBuilder())
+    }
 }
 
 fun rootPublicationComponentName(module: KotlinGradleModule) =

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

@@ -102,7 +102,7 @@ internal open class LegacyMappedVariant(
     override val fragmentName: String
         get() = fragmentForDefaultSourceSet.fragmentName + "Variant"
 
-    override val directRefinesDependencies: Iterable<KotlinModuleFragment>
+    override val directRefinesDependencies: Iterable<KotlinGradleFragment>
         get() = fragmentForDefaultSourceSet.directRefinesDependencies
 
     override val declaredModuleDependencies: Iterable<KotlinModuleDependency>
@@ -239,4 +239,4 @@ internal fun mapTargetCompilationsToKpmVariants(target: AbstractKotlinTarget, pu
             VariantPublishingConfigurator.get(target.project).configurePublishing(request)
         }
     }
-}
+}

libraries/tools/kotlin-project-model/src/main/kotlin/KotlinModule.kt

@@ -7,8 +7,7 @@ package org.jetbrains.kotlin.project.model
 
 import java.io.Serializable
 
-// TODO sealed with an abstract subclass? this will make exhaustive checks work
+sealed class KotlinModuleIdentifier(open val moduleClassifier: String?): Serializable
-open class KotlinModuleIdentifier(open val moduleClassifier: String?): Serializable
 
 // TODO consider id: Any, to allow IDs with custom equality?
 data class LocalModuleIdentifier(

settings.gradle

@@ -227,6 +227,7 @@ include ":benchmarks",
         ":tools:kotlinp",
         ":kotlin-project-model",
         ":kotlin-gradle-plugin-api",
+        ":kotlin-gradle-plugin-idea",
         ":kotlin-gradle-plugin-dsl-codegen",
         ":kotlin-gradle-plugin-npm-versions-codegen",
         ":kotlin-gradle-statistics",
@@ -631,6 +632,7 @@ project(':kotlin-sam-with-receiver-compiler-plugin').projectDir = "$rootDir/plug
 project(':tools:kotlinp').projectDir = "$rootDir/libraries/tools/kotlinp" as File
 project(':kotlin-project-model').projectDir = "$rootDir/libraries/tools/kotlin-project-model" as File
 project(':kotlin-gradle-plugin-api').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-api" as File
+project(':kotlin-gradle-plugin-idea').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-idea" as File
 project(':kotlin-gradle-plugin-dsl-codegen').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-dsl-codegen" as File
 project(':kotlin-gradle-plugin-npm-versions-codegen').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-npm-versions-codegen" as File
 project(':kotlin-gradle-statistics').projectDir = "$rootDir/libraries/tools/kotlin-gradle-statistics" as File