[Gradle] KotlinJvmCompilerOptions: Use JvmTarget.DEFAULT as default value for jvmTarget

KTIJ-24976

generators/tests/org/jetbrains/kotlin/generators/arguments/DefaultValues.kt

@@ -24,6 +24,7 @@ open class DefaultValues(
     val defaultValue: String,
     val type: KType,
     val kotlinOptionsType: KType,
+    val prettyDefaultValue: String? = null,
     val possibleValues: List<String>? = null,
     val fromKotlinOptionConverterProp: String? = null,
     val toKotlinOptionConverterProp: String? = null,
@@ -78,16 +79,17 @@ open class DefaultValues(
     )
 
     object JvmTargetVersions : DefaultValues(
-        "null",
-        typeOf<JvmTargetDsl?>(),
+        "org.jetbrains.kotlin.gradle.dsl.JvmTarget.DEFAULT",
+        typeOf<JvmTargetDsl>(),
         typeOf<String?>(),
         possibleValues = JvmTarget.supportedValues().map { "\"${it.description}\"" },
         fromKotlinOptionConverterProp = """
         if (this != null) ${typeOf<JvmTargetDsl>()}.fromTarget(this) else null
         """.trimIndent(),
         toKotlinOptionConverterProp = """
-        this?.target
-        """.trimIndent()
+        this.target
+        """.trimIndent(),
+        prettyDefaultValue = "\"${JvmTarget.DEFAULT}\""
     )
 
     object JsEcmaVersions : DefaultValues(

generators/tests/org/jetbrains/kotlin/generators/arguments/GenerateGradleOptions.kt

@@ -878,7 +878,7 @@ private fun Printer.generateOptionDeprecation(property: KProperty1<*, *>) {
 private fun Printer.generateDoc(property: KProperty1<*, *>) {
     val description = property.findAnnotation<Argument>()!!.description
     val possibleValues = property.gradleValues.possibleValues
-    val defaultValue = property.gradleDefaultValue
+    val defaultValue = property.gradleValues.prettyDefaultValue ?: property.gradleValues.defaultValue
 
     println("/**")
     println(" * ${description.replace("\n", " ")}")

generators/tests/org/jetbrains/kotlin/generators/arguments/jvmTargetGenerator.kt

@@ -28,6 +28,8 @@ internal fun generateJvmTarget(
                 println("fun fromTarget(target: String): JvmTarget =")
                 println("    JvmTarget.values().firstOrNull { it.target == target }")
                 println("        ?: throw IllegalArgumentException(\"Unknown Kotlin JVM target: ${'$'}target\")")
+                println()
+                println("val DEFAULT = ${JvmTarget.DEFAULT.name}")
             }
             println("}")
         }

libraries/tools/kotlin-gradle-compiler-types/src/generated/kotlin/org/jetbrains/kotlin/gradle/dsl/JvmTarget.kt

@@ -25,5 +25,7 @@ enum class JvmTarget(val target: String) {
         fun fromTarget(target: String): JvmTarget =
             JvmTarget.values().firstOrNull { it.target == target }
                 ?: throw IllegalArgumentException("Unknown Kotlin JVM target: $target")
+
+        val DEFAULT = JVM_1_8
     }
 }

libraries/tools/kotlin-gradle-plugin-api/api/kotlin-gradle-plugin-api.api

@@ -100,6 +100,7 @@ public final class org/jetbrains/kotlin/gradle/dsl/JvmTarget : java/lang/Enum {
 
 public final class org/jetbrains/kotlin/gradle/dsl/JvmTarget$Companion {
 	public final fun fromTarget (Ljava/lang/String;)Lorg/jetbrains/kotlin/gradle/dsl/JvmTarget;
+	public final fun getDEFAULT ()Lorg/jetbrains/kotlin/gradle/dsl/JvmTarget;
 }
 
 public abstract interface class org/jetbrains/kotlin/gradle/dsl/KaptArguments {

libraries/tools/kotlin-gradle-plugin-api/src/common/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmCompilerOptions.kt

@@ -17,9 +17,8 @@ interface KotlinJvmCompilerOptions : org.jetbrains.kotlin.gradle.dsl.KotlinCommo
     /**
      * Target version of the generated JVM bytecode (1.8, 9, 10, ..., 20), default is 1.8
      * Possible values: "1.8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20"
-     * Default value: null
+     * Default value: "1.8"
      */
-    @get:org.gradle.api.tasks.Optional
     @get:org.gradle.api.tasks.Input
     val jvmTarget: org.gradle.api.provider.Property<org.jetbrains.kotlin.gradle.dsl.JvmTarget>
 

libraries/tools/kotlin-gradle-plugin-api/src/common/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmOptions.kt

@@ -18,15 +18,15 @@ interface KotlinJvmOptions : org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
 
     private val kotlin.String?.jvmTargetCompilerOption get() = if (this != null) org.jetbrains.kotlin.gradle.dsl.JvmTarget.fromTarget(this) else null
 
-    private val org.jetbrains.kotlin.gradle.dsl.JvmTarget?.jvmTargetKotlinOption get() = this?.target
+    private val org.jetbrains.kotlin.gradle.dsl.JvmTarget.jvmTargetKotlinOption get() = this.target
 
     /**
      * Target version of the generated JVM bytecode (1.8, 9, 10, ..., 20), default is 1.8
      * Possible values: "1.8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20"
-     * Default value: null
+     * Default value: "1.8"
      */
-    var jvmTarget: kotlin.String?
-        get() = options.jvmTarget.orNull.jvmTargetKotlinOption
+    var jvmTarget: kotlin.String
+        get() = options.jvmTarget.get().jvmTargetKotlinOption
         set(value) = options.jvmTarget.set(value.jvmTargetCompilerOption)
 
     /**

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

@@ -584,9 +584,9 @@ class KotlinJavaToolchainTest : KGPBaseTest() {
                 tasks.named("compileKotlin") {
                     doLast {
                         def actualJvmTarget = compilerOptions.jvmTarget.orNull
-                        if (actualJvmTarget != null) {
+                        if (actualJvmTarget != org.jetbrains.kotlin.gradle.dsl.JvmTarget.DEFAULT) {
                             //noinspection GroovyAssignabilityCheck
-                            throw new GradleException("Expected `jvmTarget` value is 'null' but the actual value was ${'$'}actualJvmTarget")
+                            throw new GradleException("Expected `jvmTarget` value is 'JvmTarget.DEFAULT' but the actual value was ${'$'}actualJvmTarget")
                         }
                     }
                 }

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmCompilerOptionsDefault.kt

@@ -13,7 +13,7 @@ internal abstract class KotlinJvmCompilerOptionsDefault @javax.inject.Inject con
         objectFactory.property(kotlin.Boolean::class.java).convention(false)
 
     override val jvmTarget: org.gradle.api.provider.Property<org.jetbrains.kotlin.gradle.dsl.JvmTarget> =
-        objectFactory.property(org.jetbrains.kotlin.gradle.dsl.JvmTarget::class.java)
+        objectFactory.property(org.jetbrains.kotlin.gradle.dsl.JvmTarget::class.java).convention(org.jetbrains.kotlin.gradle.dsl.JvmTarget.DEFAULT)
 
     override val moduleName: org.gradle.api.provider.Property<kotlin.String> =
         objectFactory.property(kotlin.String::class.java)

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmCompilerOptionsHelper.kt

@@ -13,7 +13,7 @@ internal object KotlinJvmCompilerOptionsHelper {
     ) {
         org.jetbrains.kotlin.gradle.dsl.KotlinCommonCompilerOptionsHelper.fillCompilerArguments(from, args)
         args.javaParameters = from.javaParameters.get()
-        args.jvmTarget = from.jvmTarget.orNull?.target
+        args.jvmTarget = from.jvmTarget.get().target
         args.moduleName = from.moduleName.orNull
         args.noJdk = from.noJdk.get()
 
@@ -27,7 +27,7 @@ internal object KotlinJvmCompilerOptionsHelper {
     ) {
         org.jetbrains.kotlin.gradle.dsl.KotlinCommonCompilerOptionsHelper.fillDefaultValues(args)
         args.javaParameters = false
-        args.jvmTarget = null
+        args.jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.DEFAULT.target
         args.moduleName = null
         args.noJdk = false
 

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

@@ -76,7 +76,7 @@ internal abstract class DefaultKotlinJavaToolchain @Inject constructor(
                         else -> jvm.javaVersion.toString()
                     }
                     JvmTarget.fromTarget(normalizedVersion)
-                }
+                }.orElse(JvmTarget.DEFAULT)
             )
         }
     }

libraries/tools/kotlin-maven-plugin/src/main/java/org/jetbrains/kotlin/maven/K2JVMCompileMojo.java

@@ -33,6 +33,7 @@ import org.jetbrains.kotlin.cli.common.ExitCode;
 import org.jetbrains.kotlin.cli.common.arguments.K2JVMCompilerArguments;
 import org.jetbrains.kotlin.cli.common.messages.MessageCollector;
 import org.jetbrains.kotlin.cli.jvm.K2JVMCompiler;
+import org.jetbrains.kotlin.config.JvmTarget;
 import org.jetbrains.kotlin.incremental.IncrementalJvmCompilerRunnerKt;
 import org.jetbrains.kotlin.maven.incremental.FileCopier;
 import org.jetbrains.kotlin.maven.incremental.MavenICReporter;
@@ -186,6 +187,8 @@ public class K2JVMCompileMojo extends KotlinCompileMojoBase<K2JVMCompilerArgumen
 
         if (jvmTarget != null) {
             arguments.setJvmTarget(jvmTarget);
+        } else {
+            arguments.setJvmTarget(JvmTarget.DEFAULT.getDescription());
         }
 
         if (jdkHome != null) {