Change classes task naming and create additional task for IDE runner

Issue #KT-26641 Fixed

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

@@ -94,6 +94,10 @@ internal abstract class KotlinSourceSetProcessor<T : AbstractKotlinCompile<*>>(
     open fun run() {
         addKotlinDirectoriesToJavaSourceSet()
         doTargetSpecificProcessing()
+
+        if (kotlinCompilation is KotlinWithJavaCompilation) {
+            createAdditionalClassesTaskForIdeRunner()
+        }
     }
 
     private fun addKotlinDirectoriesToJavaSourceSet() {
@@ -127,6 +131,16 @@ internal abstract class KotlinSourceSetProcessor<T : AbstractKotlinCompile<*>>(
         return getSourceDirectories(sourceDirectorySet).minus(getSourceDirectories(javaSourceSet.java))
     }
 
+    private fun createAdditionalClassesTaskForIdeRunner() {
+        // Workaround: as per KT-26641, when there's a Kotlin compilation with a Java source set, we create another task
+        // that has a name composed as '<IDE module name>Classes`, where the IDE module name is the default source set name:
+        val expectedClassesTaskName = "${kotlinCompilation.defaultSourceSetName}Classes"
+        project.tasks.run {
+            if (findByName(expectedClassesTaskName) == null)
+                create(expectedClassesTaskName) { task -> task.dependsOn(getByName(kotlinCompilation.compileAllTaskName)) }
+        }
+    }
+
     protected abstract fun doCreateTask(project: Project, taskName: String): T
 }
 

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

@@ -130,11 +130,7 @@ abstract class AbstractKotlinCompilation(
         )
 
     override val compileAllTaskName: String
-        get() = lowerCamelCaseName(
+        get() = lowerCamelCaseName(target.disambiguationClassifier, compilationName, "classes")
-            target.disambiguationClassifier,
-            compilationName.takeIf { it != KotlinCompilation.MAIN_COMPILATION_NAME },
-            "classes"
-        )
 
     override lateinit var compileDependencyFiles: FileCollection