Toolchain takes into account kotlin options set via Android extension.

This extension updates not common task kotlin options, but special
field in the task. Toolchain will also check this field to decide
whether it should set 'jvmTarget' or not.

^KT-47754 Fixed

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/KotlinJavaToolchainTest.kt

@@ -653,6 +653,24 @@ class KotlinJavaToolchainTest : KGPBaseTest() {
         }
     }
 
+    @DisplayName("Toolchain should take into account kotlin options that are set via android extension")
+    @GradleTestVersions(minVersion = "6.7.1")
+    @GradleTest
+    internal fun kotlinOptionsAndroidAndToolchain(gradleVersion: GradleVersion) {
+        project("android".fullProjectName, gradleVersion) {
+            useToolchainExtension(11)
+
+            //language=properties
+            gradleProperties.append(
+                """
+                kotlin.jvm.target.validation.mode = error
+                """.trimIndent()
+            )
+
+            build("assembleDebug", "-Pagp_version=${TestVersions.AGP.AGP_42}")
+        }
+    }
+
     private fun BuildResult.assertJdkHomeIsUsingJdk(
         javaexecPath: String
     ) = assertOutputContains("[KOTLIN] Kotlin compilation 'jdkHome' argument: $javaexecPath")

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/testbase/TestVersions.kt

@@ -20,4 +20,8 @@ interface TestVersions {
         val CURRENT
             get() = System.getProperty("kotlinVersion") ?: error("Required to specify kotlinVersion system property for tests")
     }
+
+    object AGP {
+        const val AGP_42 = "4.2.2"
+    }
 }

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-java-toolchain/android/build.gradle

@@ -0,0 +1,34 @@
+plugins {
+    id 'com.android.application'
+    id 'org.jetbrains.kotlin.android'
+}
+
+repositories {
+    mavenLocal()
+    google()
+    mavenCentral()
+}
+
+android {
+    compileSdkVersion 30
+    defaultConfig {
+        applicationId "com.example.myapplication"
+        minSdkVersion 30
+        targetSdkVersion 30
+        versionCode 1
+        versionName "1.0"
+    }
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-java-toolchain/android/settings.gradle

@@ -0,0 +1,21 @@
+pluginManagement {
+    repositories {
+        mavenLocal()
+        mavenCentral()
+        google()
+    }
+
+    plugins {
+        id "org.jetbrains.kotlin.jvm" version "$kotlin_version"
+        id "org.jetbrains.kotlin.android" version "$kotlin_version"
+        id "org.jetbrains.kotlin.kapt" version "$kotlin_version"
+    }
+
+    resolutionStrategy {
+        eachPlugin {
+            if (requested.id.id == "com.android.application") {
+                useModule("com.android.tools.build:gradle:$agp_version")
+            }
+        }
+    }
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-java-toolchain/android/src/main/AndroidManifest.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.example.myapplication">
+
+  <application
+      android:name="example.App">
+    <activity android:name=".MainActivity">
+      <intent-filter>
+        <action android:name="android.intent.action.MAIN" />
+        <category android:name="android.intent.category.LAUNCHER" />
+      </intent-filter>
+    </activity>
+  </application>
+
+</manifest>

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-java-toolchain/android/src/main/java/example/App.java

@@ -0,0 +1,9 @@
+package example;
+
+import android.app.Application;
+
+class App extends Application {
+    public App() {
+        super();
+    }
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-java-toolchain/android/src/main/java/example/MainActivity.kt

@@ -0,0 +1,7 @@
+package example
+
+import android.app.Activity
+
+class MainActivity : Activity() {
+
+}

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

@@ -17,8 +17,7 @@ import org.gradle.api.tasks.Internal
 import org.gradle.internal.jvm.Jvm
 import org.gradle.jvm.toolchain.*
 import org.gradle.util.GradleVersion
-import org.jetbrains.kotlin.gradle.dsl.KotlinCompile as KotlinCompileTask
-import org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptionsBase
+import org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptionsImpl
 import org.jetbrains.kotlin.gradle.tasks.KotlinJavaToolchain.Companion.TOOLCHAIN_SUPPORTED_VERSION
 import org.jetbrains.kotlin.gradle.utils.chainedFinalizeValueOnRead
 import org.jetbrains.kotlin.gradle.utils.property
@@ -31,7 +30,7 @@ internal abstract class DefaultKotlinJavaToolchain @Inject constructor(
     private val objects: ObjectFactory,
     projectLayout: ProjectLayout,
     gradle: Gradle,
-    kotlinCompileTaskProvider: () -> KotlinCompileTask<KotlinJvmOptionsBase>?
+    kotlinCompileTaskProvider: () -> KotlinCompile?
 ) : KotlinJavaToolchain {
 
     private val currentGradleVersion = GradleVersion.version(gradle.gradleVersion)
@@ -120,15 +119,19 @@ internal abstract class DefaultKotlinJavaToolchain @Inject constructor(
             ?: throw GradleException("Toolchain support is available from $TOOLCHAIN_SUPPORTED_VERSION")
 
     private abstract class JvmTargetUpdater(
-        private val kotlinCompileTaskProvider: () -> KotlinCompileTask<KotlinJvmOptionsBase>?
+        private val kotlinCompileTaskProvider: () -> KotlinCompile?
     ) {
         fun updateJvmTarget(
             jdkVersion: JavaVersion
         ) {
-            kotlinCompileTaskProvider()?.kotlinOptions {
-                if (jvmTargetField == null) {
+            kotlinCompileTaskProvider()?.let { task ->
+                // parentKotlinOptionsImpl is set from 'kotlin-android' plugin
+                val appliedJvmTargets = listOfNotNull(task.kotlinOptions, task.parentKotlinOptionsImpl.orNull)
+                    .mapNotNull { (it as KotlinJvmOptionsImpl).jvmTargetField }
+
+                if (appliedJvmTargets.isEmpty()) {
                     // For Java 9 JavaVersion returns "1.9" that is not accepted by Kotlin compiler
-                    jvmTarget = if (jdkVersion == JavaVersion.VERSION_1_9) {
+                    task.kotlinOptions.jvmTarget = if (jdkVersion == JavaVersion.VERSION_1_9) {
                         "9"
                     } else {
                         jdkVersion.toString()
@@ -141,7 +144,7 @@ internal abstract class DefaultKotlinJavaToolchain @Inject constructor(
     private class DefaultJdkSetter(
         private val providedJvm: Property<Jvm>,
         private val currentGradleVersion: GradleVersion,
-        kotlinCompileTaskProvider: () -> KotlinCompileTask<KotlinJvmOptionsBase>?
+        kotlinCompileTaskProvider: () -> KotlinCompile?
     ) : JvmTargetUpdater(kotlinCompileTaskProvider),
         KotlinJavaToolchain.JdkSetter {
 
@@ -174,7 +177,7 @@ internal abstract class DefaultKotlinJavaToolchain @Inject constructor(
 
     private inner class DefaultJavaToolchainSetter(
         private val providedJvm: Property<Jvm>,
-        kotlinCompileTaskProvider: () -> KotlinCompileTask<KotlinJvmOptionsBase>?
+        kotlinCompileTaskProvider: () -> KotlinCompile?
     ) : JvmTargetUpdater(kotlinCompileTaskProvider),
         KotlinJavaToolchain.JavaToolchainSetter {
         override fun use(