Properly set jvmTarget from toolchain for KaptGenerateStubsTask

^KT-51415 Fixed

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

@@ -13,7 +13,6 @@ import org.gradle.util.GradleVersion
 import org.jetbrains.kotlin.gradle.testbase.*
 import org.junit.jupiter.api.DisplayName
 import java.io.File
-import kotlin.io.path.ExperimentalPathApi
 import kotlin.io.path.createDirectories
 import kotlin.io.path.deleteExisting
 import kotlin.io.path.writeText
@@ -23,7 +22,6 @@ import kotlin.io.path.writeText
 class JvmTargetValidationTest : KGPBaseTest() {
 
     @DisplayName("Should produce warning if java and kotlin jvm targets are different")
-    @GradleTestVersions(minVersion = TestVersions.Gradle.G_6_7)
     @GradleTest
     internal fun shouldWarnIfJavaAndKotlinJvmTargetsAreDifferent(gradleVersion: GradleVersion) {
         project(
@@ -44,7 +42,6 @@ class JvmTargetValidationTest : KGPBaseTest() {
     }
 
     @DisplayName("Should fail the build if verification mode is 'error' and kotlin and java targets are different")
-    @GradleTestVersions(minVersion = TestVersions.Gradle.G_6_7)
     @GradleTest
     internal fun shouldFailBuildIfJavaAndKotlinJvmTargetsAreDifferent(gradleVersion: GradleVersion) {
         project(
@@ -71,7 +68,6 @@ class JvmTargetValidationTest : KGPBaseTest() {
     }
 
     @DisplayName("Should ignore if verification mode is 'ignore' and kotlin and java targets are different")
-    @GradleTestVersions(minVersion = TestVersions.Gradle.G_6_7)
     @GradleTest
     internal fun shouldNotPrintAnythingIfJavaAndKotlinJvmTargetsAreDifferent(
         gradleVersion: GradleVersion
@@ -100,7 +96,6 @@ class JvmTargetValidationTest : KGPBaseTest() {
     }
 
     @DisplayName("Should not produce warning when java and kotlin jvm targets are the same")
-    @GradleTestVersions(minVersion = TestVersions.Gradle.G_6_7)
     @GradleTest
     internal fun shouldNotWarnOnJavaAndKotlinSameJvmTargets(gradleVersion: GradleVersion) {
         project(
@@ -119,7 +114,6 @@ class JvmTargetValidationTest : KGPBaseTest() {
     }
 
     @DisplayName("Should produce Java-Kotlin jvm target incompatibility warning only for related tasks")
-    @GradleTestVersions(minVersion = TestVersions.Gradle.G_6_7)
     @GradleTest
     internal fun shouldProduceJavaKotlinJvmTargetDifferenceWarningOnlyForRelatedTasks(
         gradleVersion: GradleVersion
@@ -161,7 +155,6 @@ class JvmTargetValidationTest : KGPBaseTest() {
     }
 
     @DisplayName("Should correctly validate JVM targets in mixed Kotlin/Java projects that are using <JDK1.8")
-    @GradleTestVersions(minVersion = TestVersions.Gradle.G_6_7)
     @GradleTest
     internal fun oldJdkMixedJavaKotlinTargetVerification(gradleVersion: GradleVersion) {
         project(
@@ -193,7 +186,6 @@ class JvmTargetValidationTest : KGPBaseTest() {
     }
 
     @DisplayName("Should skip JVM target validation if no Kotlin sources are available")
-    @GradleTestVersions(minVersion = TestVersions.Gradle.G_6_7)
     @GradleTest
     internal fun shouldSkipJvmTargetValidationNoKotlinSources(gradleVersion: GradleVersion) {
         project(
@@ -254,7 +246,6 @@ class JvmTargetValidationTest : KGPBaseTest() {
 
     @DisplayName("Should do JVM target validation if java sources are added and configuration cache is reused")
     @GradleTest
-    @ExperimentalPathApi
     internal fun shouldDoJvmTargetValidationOnNewJavaSourcesAndConfigurationCacheReuse(gradleVersion: GradleVersion) {
         project(
             projectName = "simple".fullProjectName,
@@ -302,6 +293,43 @@ class JvmTargetValidationTest : KGPBaseTest() {
         }
     }
 
+    @DisplayName("Validation should work correctly for KaptGenerateStubs task")
+    @GradleTestVersions
+    @GradleTest
+    internal fun kaptGenerateStubsValidateCorrect(gradleVersion: GradleVersion) {
+        project(
+            projectName = "kapt2/simple",
+            gradleVersion = gradleVersion,
+            buildJdk = getJdk11().javaHome
+        ) {
+            //language=properties
+            gradleProperties.append(
+                """
+                # suppress inspection "UnusedProperty"
+                kotlin.jvm.target.validation.mode = error
+                """.trimIndent()
+            )
+
+            val toolchainJavaVersion = if (gradleVersion < GradleVersion.version("6.9")) {
+                15
+            } else {
+                16
+            }
+            buildGradle.append(
+                """
+                
+                kotlin {
+                    jvmToolchain {
+                        languageVersion.set(JavaLanguageVersion.of($toolchainJavaVersion))
+                    }
+                }
+                """.trimIndent()
+            )
+
+            build("assemble", forceOutput = true)
+        }
+    }
+
     private fun TestProject.setJavaCompilationCompatibility(
         target: JavaVersion
     ) {

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/internal/kapt/KaptGenerateStubsTask.kt

@@ -26,6 +26,7 @@ import org.gradle.work.NormalizeLineEndings
 import org.gradle.workers.WorkerExecutor
 import org.jetbrains.kotlin.cli.common.arguments.K2JVMCompilerArguments
 import org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptionsImpl
+import org.jetbrains.kotlin.gradle.report.BuildReportMode
 import org.jetbrains.kotlin.gradle.tasks.KaptGenerateStubs
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 import org.jetbrains.kotlin.gradle.tasks.toSingleCompilerPluginOptions
@@ -123,6 +124,20 @@ abstract class KaptGenerateStubsTask @Inject constructor(
             )
         )
 
+        // Also use KotlinOptions configuration that was directly set to this task
+        // as 'compileKotlinArgumentsContributor' has KotlinOptions from linked KotlinCompile task
+        listOfNotNull(kotlinOptions, parentKotlinOptions.orNull)
+            .map { it as KotlinJvmOptionsImpl }
+            .forEach {
+                it.updateArguments(args)
+            }
+
+        // Copied from KotlinCompile
+        defaultKotlinJavaToolchain.get().updateJvmTarget(this, args)
+        if (reportingSettings().buildReportMode == BuildReportMode.VERBOSE) {
+            args.reportPerf = true
+        }
+
         val pluginOptionsWithKapt = pluginOptions.toSingleCompilerPluginOptions().withWrappedKaptOptions(withApClasspath = kaptClasspath)
         args.pluginOptions = (pluginOptionsWithKapt.arguments).toTypedArray()