Do not set api version to language version when language version is null

#KT-21852 fixed
    #KT-21574 fixed

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/argumentUtils.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.cli.common.arguments
 
+import com.intellij.util.text.VersionComparatorUtil
 import java.util.*
 import kotlin.reflect.KClass
 import kotlin.reflect.KMutableProperty1
@@ -98,4 +99,10 @@ fun <T : Any> collectProperties(kClass: KClass<T>, inheritedOnly: Boolean): List
     return properties.filter {
         it.visibility == KVisibility.PUBLIC && it.findAnnotation<Transient>() == null
     }
+}
+
+fun CommonCompilerArguments.setApiVersionToLanguageVersionIfNeeded() {
+    if (languageVersion != null && VersionComparatorUtil.compare(languageVersion, apiVersion) < 0) {
+        apiVersion = languageVersion
+    }
 }

idea/idea-analysis/src/org/jetbrains/kotlin/idea/compiler/configuration/KotlinCommonCompilerArgumentsHolder.kt

@@ -21,6 +21,7 @@ import com.intellij.openapi.project.Project
 import com.intellij.util.text.VersionComparatorUtil
 import org.jdom.Element
 import org.jetbrains.kotlin.cli.common.arguments.CommonCompilerArguments
+import org.jetbrains.kotlin.cli.common.arguments.setApiVersionToLanguageVersionIfNeeded
 import org.jetbrains.kotlin.config.SettingConstants.KOTLIN_COMMON_COMPILER_ARGUMENTS_SECTION
 import org.jetbrains.kotlin.config.detectVersionAutoAdvance
 import org.jetbrains.kotlin.config.dropVersionsIfNecessary
@@ -41,10 +42,7 @@ class KotlinCommonCompilerArgumentsHolder(project: Project) : BaseKotlinCompiler
 
         update {
             // To fix earlier configurations with incorrect combination of language and API version
-            if (VersionComparatorUtil.compare(languageVersion, apiVersion) < 0) {
+            setApiVersionToLanguageVersionIfNeeded()
-                apiVersion = languageVersion
-            }
-
             detectVersionAutoAdvance()
         }
     }

idea/testData/configuration/apiVersionWithoutLanguageVersion/.idea/kotlinc.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Kotlin2JvmCompilerArguments">
+    <option name="jvmTarget" value="1.8" />
+  </component>
+  <component name="KotlinCommonCompilerArguments">
+    <option name="apiVersion" value="1.1" />
+  </component>
+</project>

idea/testData/configuration/apiVersionWithoutLanguageVersion/.idea/libraries/KotlinJavaRuntime.xml

@@ -0,0 +1,10 @@
+<component name="libraryTable">
+  <library name="KotlinJavaRuntime">
+    <CLASSES>
+      <root url="jar://$PROJECT_DIR$/lib/kotlin-runtime.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES>
+    </SOURCES>
+  </library>
+</component>

idea/testData/configuration/apiVersionWithoutLanguageVersion/.idea/misc.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="true" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>

idea/testData/configuration/apiVersionWithoutLanguageVersion/.idea/modules.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/module.iml" filepath="$PROJECT_DIR$/module.iml" />
+    </modules>
+  </component>
+</project>

idea/testData/configuration/apiVersionWithoutLanguageVersion/module.iml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <orderEntry type="library" name="KotlinJavaRuntime" level="project" />
+  </component>
+</module>
+

idea/tests/org/jetbrains/kotlin/idea/configuration/ConfigureKotlinInTempDirTest.kt

@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.idea.configuration
 import com.intellij.openapi.application.ApplicationManager
 import com.intellij.openapi.application.impl.ApplicationImpl
 import com.intellij.openapi.util.io.FileUtil
+import org.jetbrains.kotlin.config.ApiVersion
 import org.jetbrains.kotlin.config.KotlinFacetSettingsProvider
 import org.jetbrains.kotlin.config.LanguageVersion
 import org.jetbrains.kotlin.idea.compiler.configuration.KotlinCommonCompilerArgumentsHolder
@@ -121,4 +122,10 @@ class ConfigureKotlinInTempDirTest : AbstractConfigureKotlinTest() {
         val moduleFileContentAfter = String(module.moduleFile!!.contentsToByteArray())
         Assert.assertEquals(moduleFileContentBefore, moduleFileContentAfter)
     }
+
+    fun testApiVersionWithoutLanguageVersion() {
+        KotlinCommonCompilerArgumentsHolder.getInstance(myProject)
+        val settings = myProject.getLanguageVersionSettings()
+        Assert.assertEquals(ApiVersion.KOTLIN_1_1, settings.apiVersion)
+    }
 }

jps-plugin/jps-tests/test/org/jetbrains/kotlin/jps/build/KotlinJpsBuildTest.kt

@@ -638,6 +638,19 @@ open class KotlinJpsBuildTest : AbstractKotlinJpsBuildTestCase() {
         assertFilesNotExistInOutput(myProject.modules.get(0), "_DefaultPackage.class")
     }
 
+    fun testDefaultLanguageVersionCustomApiVersion() {
+        initProject(JVM_FULL_RUNTIME)
+        buildAllModules().assertFailed()
+
+        assertEquals(1, myProject.modules.size)
+        val module = myProject.modules.first()
+        val args = JpsKotlinCompilerSettings.getCommonCompilerArguments(module)
+        args.apiVersion = "1.2"
+        JpsKotlinCompilerSettings.setCommonCompilerArguments(myProject, args)
+
+        buildAllModules().assertSuccessful()
+    }
+
     fun testKotlinJavaProject() {
         doTestWithRuntime()
     }

jps-plugin/src/org/jetbrains/kotlin/jps/model/KotlinCommonCompilerArgumentsSerializer.kt

@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.jps.model
 import com.intellij.util.text.VersionComparatorUtil
 import org.jetbrains.jps.model.JpsProject
 import org.jetbrains.kotlin.cli.common.arguments.CommonCompilerArguments
+import org.jetbrains.kotlin.cli.common.arguments.setApiVersionToLanguageVersionIfNeeded
 import org.jetbrains.kotlin.config.SettingConstants.KOTLIN_COMMON_COMPILER_ARGUMENTS_SECTION
 import org.jetbrains.kotlin.jps.JpsKotlinCompilerSettings
 
@@ -26,9 +27,7 @@ internal class KotlinCommonCompilerArgumentsSerializer : BaseJpsCompilerSettings
         KOTLIN_COMMON_COMPILER_ARGUMENTS_SECTION, CommonCompilerArguments::DummyImpl
 ) {
     override fun onLoad(project: JpsProject, settings: CommonCompilerArguments.DummyImpl) {
-        if (VersionComparatorUtil.compare(settings.languageVersion, settings.apiVersion) < 0) {
+        settings.setApiVersionToLanguageVersionIfNeeded()
-            settings.apiVersion = settings.languageVersion
-        }
         JpsKotlinCompilerSettings.setCommonCompilerArguments(project, settings)
     }
 }

jps-plugin/testData/general/DefaultLanguageVersionCustomApiVersion/kotlinProject.iml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="jdk" jdkName="IDEA_JDK" jdkType="JavaSDK" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="module" module-name="kotlinProject" />
+  </component>
+</module>

jps-plugin/testData/general/DefaultLanguageVersionCustomApiVersion/kotlinProject.ipr

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <option name="DEFAULT_COMPILER" value="Javac" />
+  </component>
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/kotlinProject.iml" filepath="$PROJECT_DIR$/kotlinProject.iml" />
+    </modules>
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_6" assert-keyword="true" jdk-15="true" project-jdk-name="IDEA_JDK" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+  <component name="KotlinCommonCompilerArguments">
+    <option name="apiVersion" value="1.1" />
+  </component>
+</project>

jps-plugin/testData/general/DefaultLanguageVersionCustomApiVersion/src/main.kt

@@ -0,0 +1,5 @@
+package test
+
+fun main(args: Array<String>) {
+    arrayListOf(1, 2, 3).fill(0)
+}