Fix resourcesDir that cannot be imported due to not being a File

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

@@ -9,9 +9,11 @@ import org.gradle.api.Named
 import org.gradle.api.attributes.HasAttributes
 import org.gradle.api.file.ConfigurableFileCollection
 import org.gradle.api.file.FileCollection
+import java.io.File
 
 interface KotlinCompilationOutput {
-    var resourcesDir: Any
+    var resourcesDirProvider: Any
+    val resourcesDir: File
     val classesDirs: ConfigurableFileCollection
 
     val allOutputs: FileCollection

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

@@ -10,11 +10,12 @@ import org.gradle.api.file.ConfigurableFileCollection
 import org.gradle.api.file.FileCollection
 import org.jetbrains.kotlin.gradle.plugin.KotlinCompilationOutput
 import org.jetbrains.kotlin.gradle.utils.isGradleVersionAtLeast
+import java.io.File
 import java.util.concurrent.Callable
 
 class DefaultKotlinCompilationOutput(
-    project: Project,
+    private val project: Project,
-    override var resourcesDir: Any
+    override var resourcesDirProvider: Any
 ) : KotlinCompilationOutput, Callable<FileCollection> {
 
     override val classesDirs: ConfigurableFileCollection = project.files()
@@ -24,6 +25,9 @@ class DefaultKotlinCompilationOutput(
         from(Callable { resourcesDir })
     }
 
+    override val resourcesDir: File
+        get() = project.file(resourcesDirProvider)
+
     override fun call(): FileCollection = allOutputs
 }
 
@@ -34,7 +38,10 @@ class KotlinWithJavaCompilationOutput(
     private val javaSourceSetOutput
         get() = compilation.javaSourceSet.output
 
-    override var resourcesDir: Any
+    override val resourcesDir: File
+        get() = javaSourceSetOutput.resourcesDir
+
+    override var resourcesDirProvider: Any
         get() = javaSourceSetOutput.resourcesDir
         set(value) { javaSourceSetOutput.setResourcesDir(value) }