[Gradle] Implement kotlin-gradle-plugin-annotations module

This will include Internal* and *Experimental annotations for the
Kotlin Gradle Plugin. The separate module is proposed, so that
additional modules can use those annotations without
a dependency to the full kotlin-gradle-plugin-api module
(see -idea modules)

^KT-54029 WIP

build.gradle.kts

@@ -380,6 +380,7 @@ val projectsWithEnabledContextReceivers by extra {
 val gradlePluginProjects = listOf(
     ":kotlin-gradle-plugin",
     ":kotlin-gradle-plugin-api",
+    ":kotlin-gradle-plugin-annotations",
     ":kotlin-gradle-plugin-idea",
     ":kotlin-gradle-plugin-idea-proto",
     ":kotlin-gradle-plugin-kpm-android",

buildSrc/src/main/kotlin/tasks.kt

@@ -44,6 +44,7 @@ val kotlinGradlePluginAndItsRequired = arrayOf(
     ":kotlin-daemon-client",
     ":kotlin-project-model",
     ":kotlin-gradle-plugin-api",
+    ":kotlin-gradle-plugin-annotations",
     ":kotlin-gradle-plugin-idea",
     ":kotlin-gradle-plugin-idea-proto",
     ":kotlin-gradle-plugin",

gradle/verification-metadata.xml

@@ -18,6 +18,7 @@
          <trust group="org.jetbrains.kotlin" name="kotlin-daemon-embeddable"/>
          <trust group="org.jetbrains.kotlin" name="kotlin-gradle-plugin"/>
          <trust group="org.jetbrains.kotlin" name="kotlin-gradle-plugin-api"/>
+         <trust group="org.jetbrains.kotlin" name="kotlin-gradle-plugin-annotations"/>
          <trust group="org.jetbrains.kotlin" name="kotlin-gradle-plugin-model"/>
          <trust group="org.jetbrains.kotlin" name="kotlin-gradle-plugin-idea"/>
          <trust group="org.jetbrains.kotlin" name="kotlin-gradle-plugin-idea-proto"/>

libraries/tools/kotlin-gradle-plugin-annotations/build.gradle.kts

@@ -0,0 +1,12 @@
+plugins {
+    kotlin("jvm")
+}
+
+configureKotlinCompileTasksGradleCompatibility()
+
+publish()
+standardPublicJars()
+
+dependencies {
+    compileOnly(kotlinStdlib())
+}

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

@@ -0,0 +1,13 @@
+/*
+ * Copyright 2010-2022 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
+
+@RequiresOptIn(
+    message = "Experimental API in the Kotlin Gradle Plugin: No stability guarantees can be provided. " +
+            "The API could get removed in the future without replacement",
+    level = RequiresOptIn.Level.WARNING
+)
+annotation class ExperimentalKotlinGradlePluginApi

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

@@ -0,0 +1,12 @@
+/*
+ * Copyright 2010-2022 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
+
+@RequiresOptIn(
+    message = "This API is not intended to be used outside of JetBrains / outside the Kotlin Gradle Plugin",
+    level = RequiresOptIn.Level.ERROR
+)
+annotation class InternalKotlinGradlePluginApi

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

@@ -4,6 +4,7 @@ plugins {
 }
 
 dependencies {
+    commonApi(project(":kotlin-gradle-plugin-annotations"))
     commonApi(project(":native:kotlin-native-utils"))
     commonApi(project(":kotlin-project-model"))
     commonImplementation(project(":kotlin-tooling-core"))

settings.gradle

@@ -251,6 +251,7 @@ include ":kotlin-imports-dumper-compiler-plugin",
         ":kotlin-project-model-tests-generator",
         ":kotlin-gradle-compiler-types",
         ":kotlin-gradle-plugin-api",
+        ":kotlin-gradle-plugin-annotations",
         ":kotlin-gradle-plugin-idea",
         ":kotlin-gradle-plugin-idea-proto",
         ":kotlin-gradle-plugin-idea-for-compatibility-tests",
@@ -756,6 +757,7 @@ project(':kotlin-project-model').projectDir = "$rootDir/libraries/tools/kotlin-p
 project(':kotlin-project-model-tests-generator').projectDir = "$rootDir/libraries/tools/kotlin-project-model-tests-generator" as File
 project(':kotlin-gradle-compiler-types').projectDir = "$rootDir/libraries/tools/kotlin-gradle-compiler-types" as File
 project(':kotlin-gradle-plugin-api').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-api" as File
+project(':kotlin-gradle-plugin-annotations').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-annotations" as File
 project(':kotlin-gradle-plugin-idea').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-idea" as File
 project(':kotlin-gradle-plugin-idea-proto').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-idea-proto" as File
 project(':kotlin-gradle-plugin-idea-for-compatibility-tests').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-idea-for-compatibility-tests" as File