[Gradle] Move some of the DSL to the API module

DSL exposed in the build scripts in effectively
an API, so this change moves it to the kotlin-gradle-plugin-api
subproject.

^KT-50869 In Progress

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

@@ -73,7 +73,7 @@ fun generateKotlinGradleOptions(withPrinterToFile: (targetFile: File, Printer.()
     // generate jvm interface
     val jvmInterfaceFqName = FqName("org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptions")
     val jvmOptions = gradleOptions<K2JVMCompilerArguments>()
-    withPrinterToFile(file(srcDir, jvmInterfaceFqName)) {
+    withPrinterToFile(file(apiSrcDir, jvmInterfaceFqName)) {
         generateInterface(
             jvmInterfaceFqName,
             jvmOptions,
@@ -99,7 +99,7 @@ fun generateKotlinGradleOptions(withPrinterToFile: (targetFile: File, Printer.()
     // generate js interface
     val jsInterfaceFqName = FqName("org.jetbrains.kotlin.gradle.dsl.KotlinJsOptions")
     val jsOptions = gradleOptions<K2JSCompilerArguments>()
-    withPrinterToFile(file(srcDir, jsInterfaceFqName)) {
+    withPrinterToFile(file(apiSrcDir, jsInterfaceFqName)) {
         generateInterface(
             jsInterfaceFqName,
             jsOptions,
@@ -124,7 +124,7 @@ fun generateKotlinGradleOptions(withPrinterToFile: (targetFile: File, Printer.()
     // generate JS DCE interface and implementation
     val jsDceInterfaceFqName = FqName("org.jetbrains.kotlin.gradle.dsl.KotlinJsDceOptions")
     val jsDceOptions = gradleOptions<K2JSDceArguments>()
-    withPrinterToFile(file(srcDir, jsDceInterfaceFqName)) {
+    withPrinterToFile(file(apiSrcDir, jsDceInterfaceFqName)) {
         generateInterface(
             jsDceInterfaceFqName,
             jsDceOptions,

libraries/tools/kotlin-gradle-plugin-api/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KaptExtensionConfig.kt

@@ -0,0 +1,121 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.dsl
+
+/**
+ * DSL extension used to configure KAPT stub generation and KAPT annotation processing.
+ */
+interface KaptExtensionConfig {
+
+    /**
+     * If `true`, compile classpath should be used to search for annotation processors.
+     */
+    var includeCompileClasspath: Boolean?
+
+    /**
+     * If `true`, skip body analysis if possible.
+     */
+    var useLightAnalysis: Boolean
+
+    /**
+     * If `true`, replace generated or error types with ones from the generated sources.
+     */
+    var correctErrorTypes: Boolean
+
+    /**
+     * If `true`, put initializers on fields when corresponding primary constructor parameters have a default value specified.
+     */
+    var dumpDefaultParameterValues: Boolean
+
+    /**
+     * If `true`, map diagnostic reported on kapt stubs to original locations in Kotlin sources.
+     */
+    var mapDiagnosticLocations: Boolean
+
+    /**
+     * If `true`, show errors on incompatibilities during stub generation.
+     */
+    var strictMode: Boolean
+
+    /**
+     * If `true`, strip @Metadata annotations from stubs.
+     */
+    var stripMetadata: Boolean
+
+    /**
+     * If `true`, show annotation processor timings.
+     */
+    var showProcessorTimings: Boolean
+
+    /**
+     * If `true`, detect memory leaks in annotation processors.
+     */
+    var detectMemoryLeaks: String
+
+    /**
+     * Opt-out switch for Kapt caching. Should be used when annotation processors used by this project are suspected of
+     * using anything aside from the task inputs in their logic and are not guaranteed to produce the same
+     * output on subsequent runs without input changes.
+     */
+    var useBuildCache: Boolean
+
+    /**
+     * If true keeps annotation processors added via `annotationProcessor(..)` configuration for javac java-files compilation
+     */
+    var keepJavacAnnotationProcessors: Boolean
+
+    /**
+     * Adds annotation processor with the specified [fqName] to the list of processors to run.
+     */
+    fun annotationProcessor(fqName: String)
+
+    /**
+     * Adds annotation processors with the specified [fqName] to the list of processors to run.
+     */
+    fun annotationProcessors(vararg fqName: String)
+
+    /**
+     * Configure [KaptArguments] used for annotation processing.
+     */
+    fun arguments(action: KaptArguments.() -> Unit)
+
+    /**
+     * Configure [KaptJavacOption] used for annotation processing.
+     */
+    fun javacOptions(action: KaptJavacOption.() -> Unit)
+
+    /**
+     * Gets all javac options used for KAPT.
+     */
+    fun getJavacOptions(): Map<String, String>
+}
+
+/**
+ * Interface used to specify arguments that are used during KAPT processing.
+ */
+interface KaptArguments {
+
+    /**
+     * Adds argument with the specified name and values.
+     */
+    fun arg(name: Any, vararg values: Any)
+}
+
+/**
+ * Interface used to specify javac options that are used during KAPT processing.
+ */
+interface KaptJavacOption {
+
+    /**
+     * Adds an option with name and value.
+     */
+    fun option(name: Any, value: Any)
+
+    /**
+     * Adds an option with name only (no value associated).
+     */
+    fun option(name: Any)
+}

libraries/tools/kotlin-gradle-plugin-api/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/kotlinTopLevelExtensionConfig.kt

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.dsl
+
+/**
+ * DSL extension that is used to configure Kotlin options for the entire project.
+ */
+interface KotlinTopLevelExtensionConfig {
+    val experimental: ExperimentalExtensionConfig
+
+    /**
+     * Version of the core Kotlin libraries that are added to Kotlin compile classpath, unless there is already a dependency added to this
+     * project. By default, this version is the same as the version of the used Kotlin Gradle plugin.
+     */
+    var coreLibrariesVersion: String
+
+    /**
+     * Option that tells the compiler if and how to report issues on all public API declarations without explicit visibility or return type.
+     */
+    var explicitApi: ExplicitApiMode?
+
+    /**
+     * Sets [explicitApi] option to report issues as errors.
+     */
+    fun explicitApi()
+
+    /**
+     * Sets [explicitApi] option to report issues as warnings.
+     */
+    fun explicitApiWarning()
+}
+
+interface ExperimentalExtensionConfig {
+    var coroutines: Coroutines?
+}
+
+/**
+ * Different modes that can be used to set the level of issue reporting for [KotlinTopLevelExtensionConfig.explicitApi] option.
+ */
+enum class ExplicitApiMode(private val cliOption: String) {
+    /** Report issues as errors. */
+    Strict("strict"),
+
+    /** Report issues as warnings. */
+    Warning("warning"),
+
+    /** Disable issues reporting. */
+    Disabled("disable");
+
+    fun toCompilerArg() = "-Xexplicit-api=$cliOption"
+}
+
+enum class Coroutines {
+    ENABLE,
+    WARN,
+    ERROR,
+    DEFAULT;
+
+    companion object {
+        fun byCompilerArgument(argument: String): Coroutines? =
+            values().firstOrNull { it.name.equals(argument, ignoreCase = true) }
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinProjectExtension.kt

@@ -34,9 +34,7 @@ import kotlin.reflect.KClass
 private const val KOTLIN_PROJECT_EXTENSION_NAME = "kotlin"
 
 internal fun Project.createKotlinExtension(extensionClass: KClass<out KotlinTopLevelExtension>): KotlinTopLevelExtension {
-    val kotlinExt = extensions.create(KOTLIN_PROJECT_EXTENSION_NAME, extensionClass.java, this)
-    DslObject(kotlinExt).extensions.create("experimental", ExperimentalExtension::class.java, this)
-    return topLevelExtension
+    return extensions.create(KOTLIN_PROJECT_EXTENSION_NAME, extensionClass.java, this)
 }
 
 internal val Project.topLevelExtension: KotlinTopLevelExtension
@@ -60,11 +58,15 @@ internal val Project.multiplatformExtension: KotlinMultiplatformExtension
 internal val Project.pm20Extension: KotlinPm20ProjectExtension
     get() = extensions.getByName(KOTLIN_PROJECT_EXTENSION_NAME).castIsolatedKotlinPluginClassLoaderAware()
 
-open class KotlinTopLevelExtension(internal val project: Project) {
-    val experimental: ExperimentalExtension
-        get() = DslObject(this).extensions.getByType(ExperimentalExtension::class.java)
+abstract class KotlinTopLevelExtension(internal val project: Project) : KotlinTopLevelExtensionConfig {
 
-    lateinit var coreLibrariesVersion: String
+    override val experimental: ExperimentalExtension = project.objects.newInstance(ExperimentalExtension::class.java, project)
+
+    fun experimental(action: Action<ExperimentalExtension>) {
+        action.execute(this.experimental)
+    }
+
+    override lateinit var coreLibrariesVersion: String
 
     private val toolchainSupport = ToolchainSupport.createToolchain(project)
 
@@ -95,18 +97,18 @@ open class KotlinTopLevelExtension(internal val project: Project) {
                 }
         }
 
-    var explicitApi: ExplicitApiMode? = null
+    override var explicitApi: ExplicitApiMode? = null
 
-    fun explicitApi() {
+    override fun explicitApi() {
         explicitApi = ExplicitApiMode.Strict
     }
 
-    fun explicitApiWarning() {
+    override fun explicitApiWarning() {
         explicitApi = ExplicitApiMode.Warning
     }
 }
 
-open class KotlinProjectExtension(project: Project) : KotlinTopLevelExtension(project), KotlinSourceSetContainer {
+open class KotlinProjectExtension @Inject constructor(project: Project) : KotlinTopLevelExtension(project), KotlinSourceSetContainer {
     override var sourceSets: NamedDomainObjectContainer<KotlinSourceSet>
         @Suppress("UNCHECKED_CAST")
         get() = DslObject(this).extensions.getByName("sourceSets") as NamedDomainObjectContainer<KotlinSourceSet>
@@ -291,8 +293,8 @@ open class KotlinAndroidProjectExtension(project: Project) : KotlinSingleTargetE
 
 open class ExperimentalExtension @Inject constructor(
     private val project: Project
-) {
-    var coroutines: Coroutines? = null
+) : ExperimentalExtensionConfig {
+    override var coroutines: Coroutines? = null
         set(value) {
             SingleWarningPerBuild.show(
                 project,
@@ -305,18 +307,6 @@ open class ExperimentalExtension @Inject constructor(
         }
 }
 
-enum class Coroutines {
-    ENABLE,
-    WARN,
-    ERROR,
-    DEFAULT;
-
-    companion object {
-        fun byCompilerArgument(argument: String): Coroutines? =
-            Coroutines.values().firstOrNull { it.name.equals(argument, ignoreCase = true) }
-    }
-}
-
 enum class NativeCacheKind(val produce: String?, val outputKind: CompilerOutputKind?) {
     NONE(null, null),
     DYNAMIC("dynamic_cache", CompilerOutputKind.DYNAMIC_CACHE),
@@ -326,12 +316,4 @@ enum class NativeCacheKind(val produce: String?, val outputKind: CompilerOutputK
         fun byCompilerArgument(argument: String): NativeCacheKind? =
             NativeCacheKind.values().firstOrNull { it.name.equals(argument, ignoreCase = true) }
     }
-}
-
-enum class ExplicitApiMode(private val cliOption: String) {
-    Strict("strict"),
-    Warning("warning"),
-    Disabled("disable");
-
-    fun toCompilerArg() = "-Xexplicit-api=$cliOption"
-}
+}

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

@@ -18,84 +18,78 @@ package org.jetbrains.kotlin.gradle.plugin
 
 import groovy.lang.Closure
 import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.dsl.KaptArguments
+import org.jetbrains.kotlin.gradle.dsl.KaptExtensionConfig
+import org.jetbrains.kotlin.gradle.dsl.KaptJavacOption
 import java.util.*
 
-open class KaptExtension {
+open class KaptExtension: KaptExtensionConfig {
     open var generateStubs: Boolean = false
 
     open var inheritedAnnotations: Boolean = true
 
-    open var useLightAnalysis: Boolean = true
+    override var useLightAnalysis: Boolean = true
 
-    open var correctErrorTypes: Boolean = false
+    override var correctErrorTypes: Boolean = false
 
-    open var dumpDefaultParameterValues: Boolean = false
+    override var dumpDefaultParameterValues: Boolean = false
 
-    open var mapDiagnosticLocations: Boolean = false
+    override var mapDiagnosticLocations: Boolean = false
 
-    open var strictMode: Boolean = false
+    override var strictMode: Boolean = false
 
-    open var stripMetadata: Boolean = false
+    override var stripMetadata: Boolean = false
     
-    open var showProcessorTimings: Boolean = false
+    override var showProcessorTimings: Boolean = false
 
-    open var detectMemoryLeaks: String = "default"
+    override var detectMemoryLeaks: String = "default"
 
-    open var includeCompileClasspath: Boolean? = null
+    override var includeCompileClasspath: Boolean? = null
 
     @Deprecated("Use `annotationProcessor()` and `annotationProcessors()` instead")
     open var processors: String = ""
 
-    /**
-     * If true keeps annotation processors added via `annotationProcessor(..)` configuration for javac java-files compilation
-     */
-    open var keepJavacAnnotationProcessors: Boolean = false
+    override var keepJavacAnnotationProcessors: Boolean = false
 
-    /** Opt-out switch for Kapt caching. Should be used when annotation processors used by this project are suspected of
-     * using anything aside from the task inputs in their logic and are not guaranteed to produce the same
-     * output on subsequent runs without input changes. */
-    var useBuildCache: Boolean = true
+    override var useBuildCache: Boolean = true
 
     private val apOptionsActions =
-        mutableListOf<(KaptAnnotationProcessorOptions) -> Unit>()
+        mutableListOf<(KaptArguments) -> Unit>()
 
     private val javacOptionsActions =
-        mutableListOf<(KaptJavacOptionsDelegate) -> Unit>()
-
-    private var apOptionsClosure: Closure<*>? = null
-    private var javacOptionsClosure: Closure<*>? = null
+        mutableListOf<(KaptJavacOption) -> Unit>()
 
     @Suppress("DEPRECATION")
-    open fun annotationProcessor(fqName: String) {
+    override fun annotationProcessor(fqName: String) {
         val oldProcessors = this.processors
         this.processors = if (oldProcessors.isEmpty()) fqName else "$oldProcessors,$fqName"
     }
 
-    open fun annotationProcessors(vararg fqName: String) {
+    override fun annotationProcessors(vararg fqName: String) {
         fqName.forEach(this::annotationProcessor)
     }
 
-    open fun arguments(closure: Closure<*>) {
+    fun arguments(closure: Closure<*>) {
         apOptionsActions += { apOptions ->
-            apOptions.execute(closure)
+            apOptions.executeClosure(closure)
         }
     }
 
-    open fun arguments(action: KaptAnnotationProcessorOptions.() -> Unit) {
+    override fun arguments(action: KaptArguments.() -> Unit) {
         apOptionsActions += action
     }
 
     open fun javacOptions(closure: Closure<*>) {
-        this.javacOptionsActions += { javacOptions ->
-            javacOptions.execute(closure)
+        javacOptionsActions += { javacOptions ->
+            javacOptions.executeClosure(closure)
         }
     }
 
-    open fun javacOptions(action: KaptJavacOptionsDelegate.() -> Unit) {
+    override fun javacOptions(action: KaptJavacOption.() -> Unit) {
         javacOptionsActions += action
     }
 
-    fun getJavacOptions(): Map<String, String> {
+    override fun getJavacOptions(): Map<String, String> {
         val result = KaptJavacOptionsDelegate()
         javacOptionsActions.forEach { it(result) }
         return result.options
@@ -123,25 +117,25 @@ open class KaptAnnotationProcessorOptions(
     @Suppress("unused") open val project: Project,
     @Suppress("unused") open val variant: Any?,
     @Suppress("unused") open val android: Any?
-) {
+): KaptArguments {
     internal val options = LinkedHashMap<String, String>()
 
     @Suppress("unused")
-    open fun arg(name: Any, vararg values: Any) {
+    override fun arg(name: Any, vararg values: Any) {
         options.put(name.toString(), values.joinToString(" "))
     }
 
     fun execute(closure: Closure<*>) = executeClosure(closure)
 }
 
-open class KaptJavacOptionsDelegate {
+open class KaptJavacOptionsDelegate: KaptJavacOption {
     internal val options = LinkedHashMap<String, String>()
 
-    open fun option(name: Any, value: Any) {
+    override fun option(name: Any, value: Any) {
         options.put(name.toString(), value.toString())
     }
 
-    open fun option(name: Any) {
+    override fun option(name: Any) {
         options.put(name.toString(), "")
     }