Kotlin Gradle Plugin: Expose default compiler arguments via compilation task API

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

@@ -21,6 +21,7 @@ import org.gradle.api.Task
 
 interface CompilerArgumentAware {
     val serializedCompilerArguments: List<String>
+    val defaultSerializedCompilerArguments: List<String>
 }
 
 interface KotlinCompile<T : KotlinCommonOptions> : Task, CompilerArgumentAware {

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

@@ -26,7 +26,7 @@ import org.jetbrains.kotlin.incremental.ChangedFiles
 import java.io.File
 
 internal open class KotlinCompileCommon : AbstractKotlinCompile<K2MetadataCompilerArguments>() {
-    override fun populateCompilerArguments(): K2MetadataCompilerArguments =
+    override fun populateCompilerArguments(defaultsOnly: Boolean): K2MetadataCompilerArguments =
             K2MetadataCompilerArguments()
 
     override fun getSourceRoots(): SourceRoots =

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

@@ -53,7 +53,7 @@ const val KOTLIN_BUILD_DIR_NAME = "kotlin"
 const val USING_EXPERIMENTAL_INCREMENTAL_MESSAGE = "Using experimental kotlin incremental compilation"
 
 abstract class AbstractKotlinCompile<T : CommonCompilerArguments>() : AbstractCompile(), CompilerArgumentAware {
-    abstract protected fun populateCompilerArguments(): T
+    abstract protected fun populateCompilerArguments(defaultsOnly: Boolean = false): T
 
     protected val additionalClasspath = arrayListOf<File>()
     protected val compileClasspath: Iterable<File>
@@ -67,6 +67,13 @@ abstract class AbstractKotlinCompile<T : CommonCompilerArguments>() : AbstractCo
             return ArgumentUtils.convertArgumentsToStringList(arguments)
         }
 
+    override val defaultSerializedCompilerArguments: List<String>
+        get() {
+            val arguments = populateCompilerArguments(true)
+            arguments.setupCommonCompilerArgs()
+            return ArgumentUtils.convertArgumentsToStringList(arguments)
+        }
+
     private val kotlinExt: KotlinProjectExtension
             get() = project.extensions.findByType(KotlinProjectExtension::class.java)!!
 
@@ -180,9 +187,11 @@ open class KotlinCompile : AbstractKotlinCompile<K2JVMCompilerArguments>(), Kotl
     override fun findKotlinCompilerJar(project: Project): File? =
             findKotlinJvmCompilerJar(project)
 
-    override fun populateCompilerArguments(): K2JVMCompilerArguments {
+    override fun populateCompilerArguments(defaultsOnly: Boolean): K2JVMCompilerArguments {
         val args = K2JVMCompilerArguments().apply { fillDefaultValues() }
 
+        if (defaultsOnly) return args
+
         handleKaptProperties()
         args.pluginClasspaths = pluginOptions.classpath.toTypedArray()
         args.pluginOptions = pluginOptions.arguments.toTypedArray()
@@ -320,8 +329,11 @@ open class Kotlin2JsCompile() : AbstractKotlinCompile<K2JSCompilerArguments>(),
     override fun findKotlinCompilerJar(project: Project): File? =
             findKotlinJsCompilerJar(project)
 
-    override fun populateCompilerArguments(): K2JSCompilerArguments {
+    override fun populateCompilerArguments(defaultsOnly: Boolean): K2JSCompilerArguments {
         val args = K2JSCompilerArguments().apply { fillDefaultValues() }
+
+        if (defaultsOnly) return args
+
         args.outputFile = outputFile
         kotlinOptionsImpl.updateArguments(args)
         return args