Prohibit JVM target 1.6

But still compile stdlib, reflect, kotlin.test and scripting runtimes
with JVM target 1.6 to simplify migration from Kotlin 1.6 to 1.7.

 #KT-45165 Fixed

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

@@ -37,7 +37,7 @@ open class DefaultValues(val defaultValue: String, val possibleValues: List<Stri
 
     object JvmTargetVersions : DefaultValues(
         "null",
-        JvmTarget.values().map { "\"${it.description}\"" }
+        JvmTarget.supportedValues().map { "\"${it.description}\"" }
     )
 
     object JsEcmaVersions : DefaultValues(

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JVMCompilerArguments.kt

@@ -75,7 +75,7 @@ class K2JVMCompilerArguments : CommonCompilerArguments() {
     @Argument(
         value = "-jvm-target",
         valueDescription = "<version>",
-        description = "Target version of the generated JVM bytecode (1.6 (DEPRECATED), 1.8, 9, 10, ..., 18), default is 1.8"
+        description = "Target version of the generated JVM bytecode (1.8, 9, 10, ..., 18), default is 1.8"
     )
     var jvmTarget: String? by NullableStringFreezableVar(null)
 
@@ -466,7 +466,8 @@ Also sets `-jvm-target` value equal to the selected JDK version"""
 
     @Argument(
         value = "-Xsuppress-deprecated-jvm-target-warning",
-        description = "Suppress deprecation warning about deprecated JVM target versions"
+        description = "Suppress deprecation warning about deprecated JVM target versions.\n" +
+                "This option has no effect and will be deleted in a future version."
     )
     var suppressDeprecatedJvmTargetWarning: Boolean by FreezableVar(false)
 

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/jvmArguments.kt

@@ -56,10 +56,10 @@ fun CompilerConfiguration.setupJvmSpecificArguments(arguments: K2JVMCompilerArgu
         val jvmTarget = JvmTarget.fromString(jvmTargetValue)
         if (jvmTarget != null) {
             put(JVMConfigurationKeys.JVM_TARGET, jvmTarget)
-            if (jvmTarget == JvmTarget.JVM_1_6 && !arguments.suppressDeprecatedJvmTargetWarning) {
+            if (jvmTarget == JvmTarget.JVM_1_6 && !isJvmTarget6Allowed()) {
                 messageCollector.report(
-                    STRONG_WARNING,
+                    ERROR,
-                    "JVM target 1.6 is deprecated and will be removed in a future release. Please migrate to JVM target 1.8 or above"
+                    "JVM target 1.6 is no longer supported. Please migrate to JVM target 1.8 or above"
                 )
             }
         } else {
@@ -353,3 +353,6 @@ private val CompilerConfiguration.messageCollector: MessageCollector
 
 private fun getJavaVersion(): Int =
     System.getProperty("java.specification.version")?.substringAfter('.')?.toIntOrNull() ?: 6
+
+private fun isJvmTarget6Allowed(): Boolean =
+    K2JVMCompiler::class.java.classLoader.getResource("META-INF/unsafe-allow-jvm6") != null

compiler/config.jvm/src/org/jetbrains/kotlin/config/JvmTarget.kt

@@ -55,5 +55,8 @@ enum class JvmTarget(
             return if (platformDescription != null) "JVM target $platformDescription"
             else "JVM bytecode version $majorVersion"
         }
+
+        fun supportedValues(): List<JvmTarget> =
+            values().asList() - JVM_1_6
     }
 }

compiler/testData/cli/jvm/extraHelp.out

@@ -131,7 +131,8 @@ where advanced options include:
                              Specify behavior for Checker Framework compatqual annotations (NullableDecl/NonNullDecl).
                              Default value is 'enable'
   -Xsuppress-deprecated-jvm-target-warning
-                             Suppress deprecation warning about deprecated JVM target versions
+                             Suppress deprecation warning about deprecated JVM target versions.
+                             This option has no effect and will be deleted in a future version.
   -Xsuppress-missing-builtins-error
                              Suppress the "cannot access built-in declaration" error (useful with -no-stdlib)
   -Xtype-enhancement-improvements-strict-mode

compiler/testData/cli/jvm/help.out

@@ -6,7 +6,7 @@ where possible options include:
   -include-runtime           Include Kotlin runtime into the resulting JAR
   -java-parameters           Generate metadata for Java 1.8 reflection on method parameters
   -jdk-home <path>           Include a custom JDK from the specified location into the classpath instead of the default JAVA_HOME
-  -jvm-target <version>      Target version of the generated JVM bytecode (1.6 (DEPRECATED), 1.8, 9, 10, ..., 18), default is 1.8
+  -jvm-target <version>      Target version of the generated JVM bytecode (1.8, 9, 10, ..., 18), default is 1.8
   -module-name <name>        Name of the generated .kotlin_module file
   -no-jdk                    Don't automatically include the Java runtime into the classpath
   -no-reflect                Don't automatically include Kotlin reflection into the classpath

compiler/testData/cli/jvm/jvm6Target.out

@@ -1,2 +1,2 @@
-warning: JVM target 1.6 is deprecated and will be removed in a future release. Please migrate to JVM target 1.8 or above
+error: JVM target 1.6 is no longer supported. Please migrate to JVM target 1.8 or above
-OK
+COMPILATION_ERROR

compiler/testData/cli/jvm/jvmDefaultAll.out

@@ -1,3 +1,3 @@
-warning: JVM target 1.6 is deprecated and will be removed in a future release. Please migrate to JVM target 1.8 or above
+error: JVM target 1.6 is no longer supported. Please migrate to JVM target 1.8 or above
 error: '-Xjvm-default=all' is only supported since JVM target 1.8. Recompile with '-jvm-target 1.8'
 COMPILATION_ERROR

compiler/tests-common-jvm6/build.gradle.kts

@@ -8,6 +8,7 @@ project.updateJvmTarget("1.6")
 dependencies {
     api(kotlinStdlib())
     testApi(project(":kotlin-test:kotlin-test-jvm"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

core/compiler.common.jvm/build.gradle.kts

@@ -7,6 +7,7 @@ project.configureJvmToolchain(JdkMajorVersion.JDK_1_6)
 
 dependencies {
     api(project(":core:compiler.common"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

core/compiler.common/build.gradle.kts

@@ -9,6 +9,7 @@ dependencies {
     api(project(":core:util.runtime"))
     api(kotlinStdlib())
     api(project(":kotlin-annotations-jvm"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

core/descriptors.jvm/build.gradle.kts

@@ -13,6 +13,7 @@ dependencies {
     api(project(":core:deserialization.common.jvm"))
     api(project(":core:util.runtime"))
     api(commonDependency("javax.inject"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

core/descriptors.runtime/build.gradle.kts

@@ -26,6 +26,8 @@ dependencies {
     testApi(projectTests(":generators:test-generator"))
 
     testApi(intellijCore())
+
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

core/descriptors/build.gradle.kts

@@ -10,6 +10,7 @@ dependencies {
     api(project(":core:util.runtime"))
     api(kotlinStdlib())
     api(project(":kotlin-annotations-jvm"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

core/deserialization.common.jvm/build.gradle.kts

@@ -9,6 +9,7 @@ dependencies {
     api(project(":core:metadata.jvm"))
     api(project(":core:deserialization.common"))
     implementation(project(":core:compiler.common.jvm"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

core/deserialization.common/build.gradle.kts

@@ -8,6 +8,7 @@ project.configureJvmToolchain(JdkMajorVersion.JDK_1_6)
 dependencies {
     api(project(":core:compiler.common"))
     api(project(":core:metadata"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

core/deserialization/build.gradle.kts

@@ -11,6 +11,7 @@ dependencies {
     api(project(":core:util.runtime"))
     api(project(":core:descriptors"))
     api(commonDependency("javax.inject"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

core/metadata.jvm/build.gradle.kts

@@ -7,6 +7,7 @@ project.configureJvmToolchain(JdkMajorVersion.JDK_1_6)
 
 dependencies {
     api(project(":core:metadata"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

core/metadata/build.gradle.kts

@@ -8,6 +8,7 @@ project.configureJvmToolchain(JdkMajorVersion.JDK_1_6)
 dependencies {
     api(protobufLite())
     api(kotlinStdlib())
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

core/util.runtime/build.gradle.kts

@@ -7,6 +7,7 @@ project.configureJvmToolchain(JdkMajorVersion.JDK_1_6)
 
 dependencies {
     compileOnly(kotlinStdlib())
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

libraries/kotlin.test/annotations-common/build.gradle

@@ -7,6 +7,7 @@ JvmToolchain.updateJvmTarget(project, "1.6")
 dependencies {
     api kotlinStdlib("common")
     testApi project(":kotlin-test:kotlin-test-common")
+    kotlinCompilerClasspath project(':libraries:tools:stdlib-compiler-classpath')
 }
 
 tasks.withType(org.jetbrains.kotlin.gradle.dsl.KotlinCompile) {
@@ -18,4 +19,4 @@ jar {
 }
 
 configureSourcesJar()
-configureJavadocJar()
+configureJavadocJar()

libraries/kotlin.test/common/build.gradle

@@ -7,6 +7,7 @@ JvmToolchain.updateJvmTarget(project, "1.6")
 dependencies {
     api kotlinStdlib("common")
     testApi project(":kotlin-test:kotlin-test-annotations-common")
+    kotlinCompilerClasspath project(':libraries:tools:stdlib-compiler-classpath')
 }
 
 jar {

libraries/kotlin.test/junit/build.gradle

@@ -16,6 +16,7 @@ dependencies {
     expectedBy project(':kotlin-test:kotlin-test-annotations-common')
     api project(':kotlin-test:kotlin-test-jvm')
     api('junit:junit:4.13.2')
+    kotlinCompilerClasspath(project(':libraries:tools:stdlib-compiler-classpath'))
 }
 
 

libraries/kotlin.test/jvm/build.gradle

@@ -19,6 +19,7 @@ dependencies {
     api(kotlinStdlib())
     testApi(project(":kotlin-test:kotlin-test-junit"))
     testApi('junit:junit:4.13.2')
+    kotlinCompilerClasspath(project(':libraries:tools:stdlib-compiler-classpath'))
 }
 
 jar {

libraries/kotlin.test/testng/build.gradle

@@ -20,6 +20,7 @@ dependencies {
     if (includeJava9) {
         java9CompileOnly('org.testng:testng:7.0.0')
     }
+    kotlinCompilerClasspath project(':libraries:tools:stdlib-compiler-classpath')
 }
 
 jar {

libraries/reflect/api/build.gradle

@@ -29,6 +29,7 @@ dependencies {
     compileOnly project(':core:descriptors.runtime')
     compileOnly project(':core:util.runtime')
     compileOnly "org.jetbrains:annotations:13.0"
+    kotlinCompilerClasspath project(':libraries:tools:stdlib-compiler-classpath')
 }
 
 if (includeJava9) {

libraries/scripting/common/build.gradle.kts

@@ -9,6 +9,7 @@ dependencies {
     api(kotlinStdlib())
     compileOnly(project(":kotlin-reflect-api"))
     testApi(commonDependency("junit"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

libraries/scripting/dependencies-maven/build.gradle.kts

@@ -34,6 +34,7 @@ dependencies {
     testRuntimeOnly("org.slf4j:slf4j-nop:1.7.30")
     testImplementation(kotlin("reflect"))
     testImplementation(commonDependency("org.jetbrains.kotlinx", "kotlinx-coroutines-core"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

libraries/scripting/dependencies/build.gradle.kts

@@ -10,6 +10,7 @@ dependencies {
     api(project(":kotlin-scripting-common"))
     testApi(commonDependency("junit"))
     testImplementation(commonDependency("org.jetbrains.kotlinx", "kotlinx-coroutines-core"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

libraries/scripting/jvm/build.gradle.kts

@@ -10,6 +10,7 @@ dependencies {
     api(kotlinStdlib())
     api(project(":kotlin-scripting-common"))
     testApi(commonDependency("junit"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

libraries/stdlib/jdk7/build.gradle

@@ -44,6 +44,7 @@ configurations {
 dependencies {
     api project(':kotlin-stdlib')
     testApi project(':kotlin-test:kotlin-test-junit')
+    kotlinCompilerClasspath project(':libraries:tools:stdlib-compiler-classpath')
 }
 
 jar {

libraries/stdlib/jvm-minimal-for-test/build.gradle.kts

@@ -20,6 +20,7 @@ val builtins by configurations.creating {
 dependencies {
     compileOnly(project(":kotlin-stdlib"))
     builtins(project(":core:builtins"))
+    kotlinCompilerClasspath(project(":libraries:tools:stdlib-compiler-classpath"))
 }
 
 sourceSets {

libraries/stdlib/jvm/build.gradle

@@ -63,6 +63,8 @@ dependencies {
     testApi project(':kotlin-test:kotlin-test-junit')
 
     builtins project(':core:builtins')
+
+    kotlinCompilerClasspath project(':libraries:tools:stdlib-compiler-classpath')
 }
 
 jar {

libraries/tools/kotlin-annotations-jvm/build.gradle

@@ -16,6 +16,7 @@ sourceSets {
 
 dependencies {
     compileOnly DependenciesKt.kotlinBuiltins(project)
+    kotlinCompilerClasspath project(':libraries:tools:stdlib-compiler-classpath')
 }
 
 configureSourcesJar()

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

@@ -24,4 +24,4 @@ interface KotlinCommonOptions  : org.jetbrains.kotlin.gradle.dsl.KotlinCommonToo
      * Default value: false
      */
      var useFir: kotlin.Boolean
-}
+}

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

@@ -12,8 +12,8 @@ interface KotlinJvmOptions  : org.jetbrains.kotlin.gradle.dsl.KotlinCommonOption
      var javaParameters: kotlin.Boolean
 
     /**
-     * Target version of the generated JVM bytecode (1.6 (DEPRECATED), 1.8, 9, 10, ..., 18), default is 1.8
+     * Target version of the generated JVM bytecode (1.8, 9, 10, ..., 18), default is 1.8
-     * Possible values: "1.6", "1.8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18"
+     * Possible values: "1.8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18"
      * Default value: null
      */
      var jvmTarget: kotlin.String?

libraries/tools/script-runtime/build.gradle

@@ -8,6 +8,7 @@ configurePublishing(project)
 
 dependencies {
     compileOnly kotlinStdlib()
+    kotlinCompilerClasspath project(':libraries:tools:stdlib-compiler-classpath')
 }
 
 sourceSets {

libraries/tools/stdlib-compiler-classpath/build.gradle.kts

@@ -0,0 +1,9 @@
+plugins {
+    java
+    id("jps-compatible")
+}
+
+sourceSets {
+    "main" { projectDefault() }
+    "test" {}
+}

settings.gradle

@@ -313,7 +313,8 @@ include ":benchmarks",
         ":kotlinx-serialization-compiler-plugin",
         ":kotlin-serialization",
         ":kotlin-serialization-unshaded",
-        ":wasm:wasm.ir"
+        ":wasm:wasm.ir",
+        ":libraries:tools:stdlib-compiler-classpath"
 
 
 include ":kotlinx-atomicfu-compiler-plugin",