Set default jvmTarget when configuring Kotlin with default configurator

idea/src/org/jetbrains/kotlin/idea/configuration/KotlinJavaModuleConfigurator.kt

@@ -17,12 +17,21 @@
 package org.jetbrains.kotlin.idea.configuration
 
 import com.intellij.openapi.extensions.Extensions
+import com.intellij.openapi.externalSystem.service.project.IdeModifiableModelsProviderImpl
 import com.intellij.openapi.module.Module
 import com.intellij.openapi.projectRoots.JavaSdk
 import com.intellij.openapi.projectRoots.JavaSdkVersion
 import com.intellij.openapi.projectRoots.Sdk
 import com.intellij.openapi.roots.libraries.Library
+import org.jetbrains.kotlin.cli.common.arguments.K2JVMCompilerArguments
+import org.jetbrains.kotlin.config.JvmTarget
+import org.jetbrains.kotlin.config.TargetPlatformKind
+import org.jetbrains.kotlin.idea.compiler.configuration.Kotlin2JvmCompilerArgumentsHolder
+import org.jetbrains.kotlin.idea.facet.getOrCreateFacet
+import org.jetbrains.kotlin.idea.facet.initializeIfNeeded
 import org.jetbrains.kotlin.idea.framework.JavaRuntimeLibraryDescription
+import org.jetbrains.kotlin.idea.util.projectStructure.allModules
+import org.jetbrains.kotlin.idea.util.projectStructure.sdk
 import org.jetbrains.kotlin.idea.versions.LibraryJarDescriptor
 import org.jetbrains.kotlin.idea.versions.isKotlinJavaRuntime
 import org.jetbrains.kotlin.resolve.TargetPlatform
@@ -74,6 +83,30 @@ open class KotlinJavaModuleConfigurator internal constructor() : KotlinWithLibra
     override val libraryMatcher: (Library) -> Boolean
         get() = ::isKotlinJavaRuntime
 
+    override fun configureKotlinSettings(modules: List<Module>) {
+        val project = modules.firstOrNull()?.project ?: return
+        val canChangeProjectSettings = project.allModules().all {
+            it.sdk?.let { JavaSdk.getInstance().getVersion(it)?.isAtLeast(JavaSdkVersion.JDK_1_8) } ?: true
+        }
+        if (canChangeProjectSettings) {
+            Kotlin2JvmCompilerArgumentsHolder.getInstance(project).update {
+                jvmTarget = "1.8"
+            }
+        }
+        else {
+            for (module in modules) {
+                val hasJdk8 = module.sdk?.let { JavaSdk.getInstance().getVersion(it)?.isAtLeast(JavaSdkVersion.JDK_1_8) }
+                if (hasJdk8 == true) {
+                    val modelsProvider = IdeModifiableModelsProviderImpl(project)
+                    val facet = module.getOrCreateFacet(modelsProvider, useProjectSettings = false, commitModel = true)
+                    val facetSettings = facet.configuration.settings
+                    facetSettings.initializeIfNeeded(module, null, TargetPlatformKind.Jvm(JvmTarget.JVM_1_8))
+                    (facetSettings.compilerArguments as? K2JVMCompilerArguments)?.jvmTarget = "1.8"
+                }
+            }
+        }
+    }
+
     companion object {
         val NAME = "java"
 

idea/src/org/jetbrains/kotlin/idea/configuration/KotlinWithLibraryConfigurator.kt

@@ -98,6 +98,8 @@ abstract class KotlinWithLibraryConfigurator internal constructor() : KotlinProj
             configureModuleWithLibrary(module, defaultPathToJar, copyLibraryIntoPath, collector)
         }
 
+        configureKotlinSettings(modulesToConfigure)
+
         collector.showNotification()
     }
 
@@ -285,6 +287,9 @@ abstract class KotlinWithLibraryConfigurator internal constructor() : KotlinProj
 
     abstract fun getLibraryJarDescriptors(sdk: Sdk?): List<LibraryJarDescriptor>
 
+    protected open fun configureKotlinSettings(modules: List<Module>) {
+    }
+
     companion object {
         val DEFAULT_LIBRARY_DIR = "lib"
 

idea/src/org/jetbrains/kotlin/idea/facet/facetUtils.kt

@@ -31,6 +31,7 @@ import org.jetbrains.kotlin.idea.compiler.configuration.Kotlin2JsCompilerArgumen
 import org.jetbrains.kotlin.idea.compiler.configuration.Kotlin2JvmCompilerArgumentsHolder
 import org.jetbrains.kotlin.idea.compiler.configuration.KotlinCommonCompilerArgumentsHolder
 import org.jetbrains.kotlin.idea.compiler.configuration.KotlinCompilerSettings
+import org.jetbrains.kotlin.idea.util.application.runWriteAction
 import org.jetbrains.kotlin.idea.versions.*
 import java.lang.reflect.Field
 
@@ -108,13 +109,20 @@ val mavenLibraryIdToPlatform: Map<String, TargetPlatformKind<*>> by lazy {
             .toMap()
 }
 
-fun Module.getOrCreateFacet(modelsProvider: IdeModifiableModelsProvider, useProjectSettings: Boolean): KotlinFacet {
+fun Module.getOrCreateFacet(modelsProvider: IdeModifiableModelsProvider,
+                            useProjectSettings: Boolean,
+                            commitModel: Boolean = false): KotlinFacet {
     val facetModel = modelsProvider.getModifiableFacetModel(this)
 
     val facet = facetModel.findFacet(KotlinFacetType.TYPE_ID, KotlinFacetType.INSTANCE.defaultFacetName)
                 ?: with(KotlinFacetType.INSTANCE) { createFacet(this@getOrCreateFacet, defaultFacetName, createDefaultConfiguration(), null) }
                         .apply { facetModel.addFacet(this) }
     facet.configuration.settings.useProjectSettings = useProjectSettings
+    if (commitModel) {
+        runWriteAction {
+            facetModel.commit()
+        }
+    }
     return facet
 }
 

idea/src/org/jetbrains/kotlin/idea/util/projectStructureUtil.kt

@@ -19,6 +19,8 @@ package org.jetbrains.kotlin.idea.util.projectStructure
 import com.intellij.openapi.module.Module
 import com.intellij.openapi.module.ModuleManager
 import com.intellij.openapi.project.Project
+import com.intellij.openapi.projectRoots.Sdk
+import com.intellij.openapi.roots.ModuleRootManager
 import com.intellij.openapi.roots.OrderEnumerator
 import com.intellij.openapi.roots.OrderRootType
 import com.intellij.openapi.roots.libraries.Library
@@ -29,6 +31,8 @@ fun Project.allModules() = ModuleManager.getInstance(this).modules.toList()
 
 fun Module.findLibrary(predicate: (Library) -> Boolean): Library? = OrderEnumerator.orderEntries(this).findLibrary(predicate)
 
+val Module.sdk: Sdk? get() = ModuleRootManager.getInstance(this).sdk
+
 fun OrderEnumerator.findLibrary(predicate: (Library) -> Boolean): Library? {
     var lib: Library? = null
     forEachLibrary { library ->

idea/tests/org/jetbrains/kotlin/idea/configuration/ConfigureKotlinTest.java

@@ -233,7 +233,7 @@ public class ConfigureKotlinTest extends AbstractConfigureKotlinTest {
     private void configureFacetAndCheckJvm(JvmTarget jvmTarget) {
         IdeModifiableModelsProviderImpl modelsProvider = new IdeModifiableModelsProviderImpl(getProject());
         try {
-            KotlinFacet facet = FacetUtilsKt.getOrCreateFacet(getModule(), modelsProvider, false);
+            KotlinFacet facet = FacetUtilsKt.getOrCreateFacet(getModule(), modelsProvider, false, false);
             TargetPlatformKind.Jvm platformKind = TargetPlatformKind.Jvm.Companion.get(jvmTarget);
             FacetUtilsKt.configureFacet(
                     facet,