Populate the SourceSets with more relevant information.

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/model/builder/KotlinModelBuilder.kt

@@ -22,13 +22,16 @@ import org.jetbrains.kotlin.gradle.plugin.KOTLIN_DSL_NAME
 import org.jetbrains.kotlin.gradle.plugin.KOTLIN_JS_DSL_NAME
 import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet
 import org.jetbrains.kotlin.gradle.plugin.getConvention
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinAndroidTarget
 import org.jetbrains.kotlin.gradle.tasks.AbstractKotlinCompile
 
 /**
  * [ToolingModelBuilder] for [KotlinProject] models.
  * This model builder is registered for base Kotlin JVM (including Android), Kotlin JS and Kotlin Common plugins.
+ *
+ * [androidTarget] should always be null for none Android plugins.
  */
-class KotlinModelBuilder(private val kotlinPluginVersion: String) : ToolingModelBuilder {
+class KotlinModelBuilder(private val kotlinPluginVersion: String, private val androidTarget: KotlinAndroidTarget?) : ToolingModelBuilder {
 
     override fun canBuild(modelName: String): Boolean {
         return modelName == KotlinProject::class.java.name
@@ -43,7 +46,7 @@ class KotlinModelBuilder(private val kotlinPluginVersion: String) : ToolingModel
                 kotlinPluginVersion,
                 projectType,
                 kotlinCompileTasks.mapNotNull {
-                    if (project.isAndroid()) it.createAndroidSourceSet() else it.createSourceSet(project, projectType)
+                    if (androidTarget != null) it.createAndroidSourceSet(androidTarget) else it.createSourceSet(project, projectType)
                 },
                 getExpectedByDependencies(project),
                 kotlinCompileTasks.first()!!.createExperimentalFeatures()
@@ -103,15 +106,24 @@ class KotlinModelBuilder(private val kotlinPluginVersion: String) : ToolingModel
          * Android Gradle plugin and as such is not populated here. The important information here that is required by
          * Android Studio are the [CompilerArguments].
          */
-        private fun AbstractKotlinCompile<*>.createAndroidSourceSet(): SourceSet {
+        private fun AbstractKotlinCompile<*>.createAndroidSourceSet(androidTarget: KotlinAndroidTarget): SourceSet {
+            val variantName = sourceSetName
+            val compilation = androidTarget.compilations.getByName(variantName)
+            // Merge all sources and resource dirs from the different Source Sets that make up this variant.
+            val sources = compilation.kotlinSourceSets.flatMap {
+                it.kotlin.srcDirs
+            }.distinctBy { it.absolutePath }
+            val resources = compilation.kotlinSourceSets.flatMap {
+                it.resources.srcDirs
+            }.distinctBy { it.absolutePath }
             return SourceSetImpl(
                 sourceSetName,
                 if (sourceSetName.contains("test", true)) SourceSet.SourceSetType.TEST else SourceSet.SourceSetType.PRODUCTION,
                 findFriendSourceSets(),
-                emptyList(), // Obtained from the Android model
-                emptyList(), // Obtained from the Android model
+                sources,
+                resources,
                 destinationDir,
-                destinationDir, // Obtained from the Android model
+                compilation.output.resourcesDir,
                 createCompilerArguments()
             )
         }

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

@@ -352,7 +352,7 @@ internal abstract class AbstractKotlinPlugin(
 
         configureAttributes(target)
         configureProjectGlobalSettings(project, kotlinPluginVersion)
-        registry.register(KotlinModelBuilder(kotlinPluginVersion))
+        registry.register(KotlinModelBuilder(kotlinPluginVersion, null))
     }
 
     companion object {
@@ -571,7 +571,7 @@ internal open class KotlinAndroidPlugin(
             project, androidTarget, tasksProvider,
             kotlinPluginVersion
         )
-        registry.register(KotlinModelBuilder(kotlinPluginVersion))
+        registry.register(KotlinModelBuilder(kotlinPluginVersion, androidTarget))
     }
 
     companion object {

libraries/tools/kotlin-gradle-plugin/src/test/kotlin/org/jetbrains/kotlin/gradle/model/builder/KotlinModelBuilderTest.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.gradle.model.builder
 
 import org.jetbrains.kotlin.gradle.model.KotlinProject
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinAndroidTarget
 import org.junit.Test
 import kotlin.test.assertFalse
 import kotlin.test.assertTrue
@@ -13,7 +14,7 @@ import kotlin.test.assertTrue
 class KotlinModelBuilderTest {
     @Test
     fun testCanBuild() {
-        val modelBuilder = KotlinModelBuilder("version")
+        val modelBuilder = KotlinModelBuilder("version", null)
         assertTrue(modelBuilder.canBuild(KotlinProject::class.java.name))
         assertFalse(modelBuilder.canBuild("wrongModel"))
     }