[Kotlin, Gradle] Add support for Kotlin generated source in Kotlin/KMP projects

From a UI perspective, these roots are still visible as normal sources due to some missing functionality in UI handling.

^KTIJ-35910

GitOrigin-RevId: d572441c4715685050982c1672bddd0e1461f7f9

plugins/kotlin/base/project-model/src/org/jetbrains/kotlin/idea/projectModel/KotlinSourceSet.kt

@@ -8,6 +8,7 @@ interface KotlinSourceSet : KotlinComponent, HasMutableExtras {
     val languageSettings: KotlinLanguageSettings
     val sourceDirs: Set<File>
     val resourceDirs: Set<File>
+    val generatedKotlinDirs: Set<File>
     val actualPlatforms: KotlinPlatformContainer
 
     /**
@@ -46,11 +47,11 @@ interface KotlinSourceSet : KotlinComponent, HasMutableExtras {
     val androidSourceSetInfo: KotlinAndroidSourceSetInfo?
 
     companion object {
-        const val COMMON_MAIN_SOURCE_SET_NAME = "commonMain"
-        const val COMMON_TEST_SOURCE_SET_NAME = "commonTest"
+        const val COMMON_MAIN_SOURCE_SET_NAME: String = "commonMain"
+        const val COMMON_TEST_SOURCE_SET_NAME: String = "commonTest"
 
         // Note. This method could not be deleted due to usage in KotlinAndroidGradleMPPModuleDataService from IDEA Core
         @Suppress("unused")
-        fun commonName(forTests: Boolean) = if (forTests) COMMON_TEST_SOURCE_SET_NAME else COMMON_MAIN_SOURCE_SET_NAME
+        fun commonName(forTests: Boolean): String = if (forTests) COMMON_TEST_SOURCE_SET_NAME else COMMON_MAIN_SOURCE_SET_NAME
     }
 }

plugins/kotlin/gradle/gradle-java/src/org/jetbrains/kotlin/idea/gradleJava/configuration/KotlinMppGradleProjectResolver.kt

@@ -203,3 +203,6 @@ internal val KotlinComponent.sourceType
 
 internal val KotlinComponent.resourceType
     get() = if (isTestComponent) ExternalSystemSourceType.TEST_RESOURCE else ExternalSystemSourceType.RESOURCE
+
+internal val KotlinComponent.generatedSourceType
+    get() = if (isTestComponent) ExternalSystemSourceType.TEST_GENERATED else ExternalSystemSourceType.SOURCE_GENERATED

plugins/kotlin/gradle/gradle-java/src/org/jetbrains/kotlin/idea/gradleJava/configuration/KotlinSourceSetDataService.kt

@@ -310,7 +310,9 @@ private fun populateNonJvmSourceRootTypes(sourceSetNode: DataNode<GradleSourceSe
 
     val externalToKotlinSourceTypes = mapOf(
         ExternalSystemSourceType.SOURCE to SourceKotlinRootType,
-        ExternalSystemSourceType.TEST to TestSourceKotlinRootType
+        ExternalSystemSourceType.SOURCE_GENERATED to SourceKotlinRootType,
+        ExternalSystemSourceType.TEST to TestSourceKotlinRootType,
+        ExternalSystemSourceType.TEST_GENERATED to TestSourceKotlinRootType
     )
     externalToKotlinSourceTypes.forEach { (externalType, kotlinType) ->
         val sourcesRoots = contentRootDataList.flatMap { it.getPaths(externalType) }

plugins/kotlin/gradle/gradle-java/src/org/jetbrains/kotlin/idea/gradleJava/configuration/mpp/moduleContentRoots.kt

@@ -12,6 +12,7 @@ import org.gradle.tooling.model.idea.IdeaContentRoot
 import org.gradle.tooling.model.idea.IdeaModule
 import org.jetbrains.kotlin.idea.gradle.configuration.kotlinSourceSetData
 import org.jetbrains.kotlin.idea.gradleJava.configuration.KotlinMppGradleProjectResolver
+import org.jetbrains.kotlin.idea.gradleJava.configuration.generatedSourceType
 import org.jetbrains.kotlin.idea.gradleJava.configuration.kotlinGradleProjectDataOrFail
 import org.jetbrains.kotlin.idea.gradleJava.configuration.mpp.KotlinMppGradleProjectResolverExtension.Result.Skip
 import org.jetbrains.kotlin.idea.gradleJava.configuration.resourceType
@@ -55,6 +56,12 @@ internal fun KotlinMppGradleProjectResolver.Context.populateContentRoots(
             null,
             dataNode
         )
+        createContentRootData(
+            sourceSet.generatedKotlinDirs,
+            sourceSet.generatedSourceType,
+            null,
+            dataNode,
+        )
 
         extensionInstance.afterPopulateContentRoots(this, dataNode, sourceSet)
     }

plugins/kotlin/gradle/gradle-tooling/impl/src/org/jetbrains/kotlin/idea/gradleTooling/KotlinMPPGradleModelImpl.kt

@@ -43,6 +43,7 @@ class KotlinSourceSetImpl @OptIn(KotlinGradlePluginVersionDependentApi::class) c
     override val languageSettings: KotlinLanguageSettings,
     override val sourceDirs: Set<File>,
     override val resourceDirs: Set<File>,
+    override val generatedKotlinDirs: Set<File>,
     override val regularDependencies: Array<KotlinDependencyId>,
     override val intransitiveDependencies: Array<KotlinDependencyId>,
     override val declaredDependsOnSourceSets: Set<String>,
@@ -62,6 +63,7 @@ class KotlinSourceSetImpl @OptIn(KotlinGradlePluginVersionDependentApi::class) c
         name = kotlinSourceSet.name,
         languageSettings = KotlinLanguageSettingsImpl(kotlinSourceSet.languageSettings),
         sourceDirs = kotlinSourceSet.sourceDirs.toMutableSet(),
+        generatedKotlinDirs = kotlinSourceSet.generatedKotlinDirs.toMutableSet(),
         resourceDirs = kotlinSourceSet.resourceDirs.toMutableSet(),
         regularDependencies = kotlinSourceSet.regularDependencies.clone(),
         intransitiveDependencies = kotlinSourceSet.intransitiveDependencies.clone(),
@@ -74,7 +76,7 @@ class KotlinSourceSetImpl @OptIn(KotlinGradlePluginVersionDependentApi::class) c
         isTestComponent = kotlinSourceSet.isTestComponent
     )
 
-    override fun toString() = name
+    override fun toString(): String = name
 
     init {
         require(allDependsOnSourceSets.containsAll(declaredDependsOnSourceSets)) {

plugins/kotlin/gradle/gradle-tooling/impl/src/org/jetbrains/kotlin/idea/gradleTooling/builders/KotlinSourceSetBuilder.kt

@@ -45,6 +45,7 @@ internal class KotlinSourceSetBuilder(
 
         val sourceDirs = sourceSetReflection.kotlin?.srcDirs ?: emptySet()
         val resourceDirs = sourceSetReflection.resources?.srcDirs ?: emptySet()
+        val generatedKotlinDirs = sourceSetReflection.generatedSources?.srcDirs?.toSet() ?: emptySet()
         val dependsOnSourceSets = sourceSetReflection.dependsOn.map { it.name }.toSet()
         val additionalVisibleSourceSets = sourceSetReflection.additionalVisibleSourceSets.map { it.name }.toSet()
 
@@ -87,6 +88,7 @@ internal class KotlinSourceSetBuilder(
             languageSettings = languageSettings,
             sourceDirs = sourceDirs,
             resourceDirs = resourceDirs,
+            generatedKotlinDirs = generatedKotlinDirs,
             regularDependencies = sourceSetDependencies,
             intransitiveDependencies = intransitiveSourceSetDependencies,
             declaredDependsOnSourceSets = dependsOnSourceSets.toMutableSet(),

plugins/kotlin/gradle/gradle-tooling/tests/test/org/jetbrains/kotlin/gradle/createKotlinMPPGradleModel.kt

@@ -81,6 +81,7 @@ internal fun createKotlinSourceSet(
     ),
     sourceDirs = emptySet(),
     resourceDirs = emptySet(),
+    generatedKotlinDirs = emptySet(),
     regularDependencies = emptyArray(),
     intransitiveDependencies = emptyArray(),
     declaredDependsOnSourceSets = declaredDependsOnSourceSets,

plugins/kotlin/gradle/multiplatform-tests-k2/test/org/jetbrains/kotlin/gradle/idea/importing/multiplatformTests/k2/KotlinMppGeneratedSourcesImportTest.kt

@@ -0,0 +1,40 @@
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package org.jetbrains.kotlin.gradle.multiplatformTests
+
+import org.jetbrains.kotlin.gradle.multiplatformTests.testFeatures.checkers.contentRoots.ContentRootsChecker
+import org.jetbrains.kotlin.test.TestMetadata
+import org.jetbrains.plugins.gradle.tooling.annotation.PluginTargetVersions
+import org.junit.Test
+
+@TestMetadata("multiplatform/core/features/generatedSources")
+class KotlinMppGeneratedSourcesImportTest : AbstractKotlinMppGradleImportingTest() {
+
+    override fun TestConfigurationDslScope.defaultTestConfiguration() {
+        onlyCheckers(ContentRootsChecker)
+        hideResourceRoots = true
+    }
+
+    @Test
+    @PluginTargetVersions(pluginVersion = "2.3.0+", gradleVersion = "7.6+")
+    fun testGeneratedInCommonMain() {
+        doTest()
+    }
+
+    @Test
+    @PluginTargetVersions(pluginVersion = "2.3.0+", gradleVersion = "7.6+")
+    fun testGeneratedInCommonTest() {
+        doTest()
+    }
+
+    @Test
+    @PluginTargetVersions(pluginVersion = "2.3.0+", gradleVersion = "7.6+")
+    fun testGeneratedInJvmMain() {
+        doTest()
+    }
+
+    @Test
+    @PluginTargetVersions(pluginVersion = "2.3.0+", gradleVersion = "7.6+")
+    fun testGeneratedInJvmTest() {
+        doTest()
+    }
+}

plugins/kotlin/idea/tests/testData/gradle/multiplatform/core/features/generatedSources/generatedInCommonMain/build.gradle.kts

@@ -0,0 +1,28 @@
+plugins {
+    kotlin("multiplatform")
+}
+
+group = "com.example"
+version = "1.0"
+
+kotlin {
+    jvm()
+    linuxX64()
+}
+
+val generatorTask = project.tasks.register("generator") {
+    val outputDirectory = project.layout.projectDirectory.dir("src/commonMain/kotlinGen")
+    outputs.dir(outputDirectory)
+    doLast {
+        outputDirectory.file("generatedCommon.kt").asFile.writeText(
+            //language=kotlin
+            """
+            fun printHello() {
+                println("hello")
+            }
+            """.trimIndent()
+        )
+    }
+}
+
+kotlin.sourceSets.getByName("commonMain").generatedKotlin.srcDir(generatorTask)

plugins/kotlin/idea/tests/testData/gradle/multiplatform/core/features/generatedSources/generatedInCommonMain/settings.gradle.kts

@@ -0,0 +1,17 @@
+pluginManagement {
+    repositories {
+        { { kts_kotlin_plugin_repositories } }
+    }
+
+    plugins {
+        kotlin("multiplatform") version "{{kgp_version}}"
+    }
+}
+
+dependencyResolutionManagement {
+    repositories {
+        { { kts_kotlin_plugin_repositories } }
+    }
+}
+
+rootProject.name = "project"

plugins/kotlin/idea/tests/testData/gradle/multiplatform/core/features/generatedSources/generatedInCommonMain/source-roots.txt

@@ -0,0 +1,39 @@
+MODULES
+project
+
+project.commonMain
+    src/commonMain/kotlin
+    src/commonMain/kotlinGen
+
+project.commonTest
+    src/commonTest/kotlin (Test)
+
+project.jvmMain
+    src/jvmMain/java (Java)
+    src/jvmMain/kotlin (Java)
+
+project.jvmTest
+    src/jvmTest/java (Java, Test)
+    src/jvmTest/kotlin (Java, Test)
+
+project.linuxMain
+    src/linuxMain/kotlin
+
+project.linuxTest
+    src/linuxTest/kotlin (Test)
+
+project.linuxX64Main
+    src/linuxX64Main/kotlin
+
+project.linuxX64Test
+    src/linuxX64Test/kotlin (Test)
+
+project.nativeMain
+    src/nativeMain/kotlin
+
+project.nativeTest
+    src/nativeTest/kotlin (Test)
+
+
+Test configuration:
+- hiding following roots: resources, android-specific roots, generated

plugins/kotlin/idea/tests/testData/gradle/multiplatform/core/features/generatedSources/generatedInCommonTest/build.gradle.kts

@@ -0,0 +1,28 @@
+plugins {
+    kotlin("multiplatform")
+}
+
+group = "com.example"
+version = "1.0"
+
+kotlin {
+    jvm()
+    linuxX64()
+}
+
+val generatorTask = project.tasks.register("generator") {
+    val outputDirectory = project.layout.projectDirectory.dir("src/commonTest/kotlinGen")
+    outputs.dir(outputDirectory)
+    doLast {
+        outputDirectory.file("generatedCommon.kt").asFile.writeText(
+            //language=kotlin
+            """
+            fun printHello() {
+                println("hello")
+            }
+            """.trimIndent()
+        )
+    }
+}
+
+kotlin.sourceSets.getByName("commonTest").generatedKotlin.srcDir(generatorTask)

plugins/kotlin/idea/tests/testData/gradle/multiplatform/core/features/generatedSources/generatedInCommonTest/settings.gradle.kts

@@ -0,0 +1,17 @@
+pluginManagement {
+    repositories {
+        { { kts_kotlin_plugin_repositories } }
+    }
+
+    plugins {
+        kotlin("multiplatform") version "{{kgp_version}}"
+    }
+}
+
+dependencyResolutionManagement {
+    repositories {
+        { { kts_kotlin_plugin_repositories } }
+    }
+}
+
+rootProject.name = "project"

plugins/kotlin/idea/tests/testData/gradle/multiplatform/core/features/generatedSources/generatedInCommonTest/source-roots.txt

@@ -0,0 +1,39 @@
+MODULES
+project
+
+project.commonMain
+    src/commonMain/kotlin
+
+project.commonTest
+    src/commonTest/kotlin (Test)
+    src/commonTest/kotlinGen (Test)
+
+project.jvmMain
+    src/jvmMain/java (Java)
+    src/jvmMain/kotlin (Java)
+
+project.jvmTest
+    src/jvmTest/java (Java, Test)
+    src/jvmTest/kotlin (Java, Test)
+
+project.linuxMain
+    src/linuxMain/kotlin
+
+project.linuxTest
+    src/linuxTest/kotlin (Test)
+
+project.linuxX64Main
+    src/linuxX64Main/kotlin
+
+project.linuxX64Test
+    src/linuxX64Test/kotlin (Test)
+
+project.nativeMain
+    src/nativeMain/kotlin
+
+project.nativeTest
+    src/nativeTest/kotlin (Test)
+
+
+Test configuration:
+- hiding following roots: resources, android-specific roots, generated

plugins/kotlin/idea/tests/testData/gradle/multiplatform/core/features/generatedSources/generatedInJvmMain/build.gradle.kts

@@ -0,0 +1,28 @@
+plugins {
+    kotlin("multiplatform")
+}
+
+group = "com.example"
+version = "1.0"
+
+kotlin {
+    jvm()
+    linuxX64()
+}
+
+val generatorTask = project.tasks.register("generator") {
+    val outputDirectory = project.layout.projectDirectory.dir("src/jvmMain/kotlinGen")
+    outputs.dir(outputDirectory)
+    doLast {
+        outputDirectory.file("generatedCommon.kt").asFile.writeText(
+            //language=kotlin
+            """
+            fun printHello() {
+                println("hello")
+            }
+            """.trimIndent()
+        )
+    }
+}
+
+kotlin.sourceSets.getByName("jvmMain").generatedKotlin.srcDir(generatorTask)

plugins/kotlin/idea/tests/testData/gradle/multiplatform/core/features/generatedSources/generatedInJvmMain/settings.gradle.kts

@@ -0,0 +1,17 @@
+pluginManagement {
+    repositories {
+        { { kts_kotlin_plugin_repositories } }
+    }
+
+    plugins {
+        kotlin("multiplatform") version "{{kgp_version}}"
+    }
+}
+
+dependencyResolutionManagement {
+    repositories {
+        { { kts_kotlin_plugin_repositories } }
+    }
+}
+
+rootProject.name = "project"

plugins/kotlin/idea/tests/testData/gradle/multiplatform/core/features/generatedSources/generatedInJvmMain/source-roots.txt

@@ -0,0 +1,39 @@
+MODULES
+project
+
+project.commonMain
+    src/commonMain/kotlin
+
+project.commonTest
+    src/commonTest/kotlin (Test)
+
+project.jvmMain
+    src/jvmMain/java (Java)
+    src/jvmMain/kotlin (Java)
+    src/jvmMain/kotlinGen (Java)
+
+project.jvmTest
+    src/jvmTest/java (Java, Test)
+    src/jvmTest/kotlin (Java, Test)
+
+project.linuxMain
+    src/linuxMain/kotlin
+
+project.linuxTest
+    src/linuxTest/kotlin (Test)
+
+project.linuxX64Main
+    src/linuxX64Main/kotlin
+
+project.linuxX64Test
+    src/linuxX64Test/kotlin (Test)
+
+project.nativeMain
+    src/nativeMain/kotlin
+
+project.nativeTest
+    src/nativeTest/kotlin (Test)
+
+
+Test configuration:
+- hiding following roots: resources, android-specific roots, generated

plugins/kotlin/idea/tests/testData/gradle/multiplatform/core/features/generatedSources/generatedInJvmTest/build.gradle.kts

@@ -0,0 +1,28 @@
+plugins {
+    kotlin("multiplatform")
+}
+
+group = "com.example"
+version = "1.0"
+
+kotlin {
+    jvm()
+    linuxX64()
+}
+
+val generatorTask = project.tasks.register("generator") {
+    val outputDirectory = project.layout.projectDirectory.dir("src/jvmTest/kotlinGen")
+    outputs.dir(outputDirectory)
+    doLast {
+        outputDirectory.file("generatedCommon.kt").asFile.writeText(
+            //language=kotlin
+            """
+            fun printHello() {
+                println("hello")
+            }
+            """.trimIndent()
+        )
+    }
+}
+
+kotlin.sourceSets.getByName("jvmTest").generatedKotlin.srcDir(generatorTask)

plugins/kotlin/idea/tests/testData/gradle/multiplatform/core/features/generatedSources/generatedInJvmTest/settings.gradle.kts

@@ -0,0 +1,17 @@
+pluginManagement {
+    repositories {
+        { { kts_kotlin_plugin_repositories } }
+    }
+
+    plugins {
+        kotlin("multiplatform") version "{{kgp_version}}"
+    }
+}
+
+dependencyResolutionManagement {
+    repositories {
+        { { kts_kotlin_plugin_repositories } }
+    }
+}
+
+rootProject.name = "project"

plugins/kotlin/idea/tests/testData/gradle/multiplatform/core/features/generatedSources/generatedInJvmTest/source-roots.txt

@@ -0,0 +1,39 @@
+MODULES
+project
+
+project.commonMain
+    src/commonMain/kotlin
+
+project.commonTest
+    src/commonTest/kotlin (Test)
+
+project.jvmMain
+    src/jvmMain/java (Java)
+    src/jvmMain/kotlin (Java)
+
+project.jvmTest
+    src/jvmTest/java (Java, Test)
+    src/jvmTest/kotlin (Java, Test)
+    src/jvmTest/kotlinGen (Java, Test)
+
+project.linuxMain
+    src/linuxMain/kotlin
+
+project.linuxTest
+    src/linuxTest/kotlin (Test)
+
+project.linuxX64Main
+    src/linuxX64Main/kotlin
+
+project.linuxX64Test
+    src/linuxX64Test/kotlin (Test)
+
+project.nativeMain
+    src/nativeMain/kotlin
+
+project.nativeTest
+    src/nativeTest/kotlin (Test)
+
+
+Test configuration:
+- hiding following roots: resources, android-specific roots, generated