kotlin-gradle-plugin-idea: Replace special -for-compatibility-tests publication

... with separate module intended to download and prepare
the `kotlin-gradle-plugin-idea` classpath used for testing
backwards compatibility.

gradle/verification-metadata.xml

@@ -20,7 +20,6 @@
          <trust group="org.jetbrains.kotlin" name="kotlin-gradle-plugin-api"/>
          <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-for-compatibility-tests"/>
          <trust group="org.jetbrains.kotlin" name="kotlin-klib-commonizer-api"/>
          <trust group="org.jetbrains.kotlin" name="kotlin-klib-commonizer-embeddable"/>
          <trust group="org.jetbrains.kotlin" name="kotlin-tooling-metadata"/>

libraries/tools/kotlin-gradle-plugin-idea-for-compatibility-tests/build.gradle.kts

@@ -0,0 +1,47 @@
+@file:Suppress("HasPlatformType")
+
+/**
+ * Version of kotlin-gradle-plugin-idea module that should be resolved for compatibility tests
+ * This version can be treated as 'minimal guaranteed backwards compatible version' of the module.
+ */
+val testedVersion = "1.7.0-dev-2723"
+
+//region Download and prepare classpath for specified tested version
+
+val classpathDestination = layout.buildDirectory.dir("classpath")
+
+val incomingClasspath by configurations.creating {
+    isCanBeConsumed = false
+    isCanBeResolved = true
+    attributes.attribute(Usage.USAGE_ATTRIBUTE, objects.named(Usage.JAVA_RUNTIME))
+    attributes.attribute(Category.CATEGORY_ATTRIBUTE, objects.named(Category.LIBRARY))
+}
+
+dependencies {
+    incomingClasspath(kotlin("gradle-plugin-idea", testedVersion))
+}
+
+val syncClasspath by tasks.register<Sync>("syncClasspath") {
+    from(incomingClasspath)
+    into(classpathDestination)
+
+    /* Test if the correct version was resolved */
+    doLast {
+        val expectedJar = destinationDir.resolve("kotlin-gradle-plugin-idea-$testedVersion.jar")
+        check(expectedJar.exists()) { "Expected $expectedJar in classpath. Found ${destinationDir.listFiles().orEmpty()}" }
+    }
+}
+
+val outgoingClasspath by configurations.creating {
+    isCanBeConsumed = true
+    isCanBeResolved = false
+    attributes.attribute(Usage.USAGE_ATTRIBUTE, objects.named(Usage.JAVA_RUNTIME))
+    attributes.attribute(Category.CATEGORY_ATTRIBUTE, objects.named(Category.LIBRARY))
+    outgoing.artifact(classpathDestination) { builtBy(syncClasspath) }
+}
+
+tasks.register<Delete>("clean") {
+    delete(project.buildDir)
+}
+
+//endregion

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

@@ -4,10 +4,6 @@ plugins {
     `maven-publish`
 }
 
-object BackwardsCompatibilityTestConfiguration {
-    const val minimalBackwardsCompatibleVersion = "1.7.0-dev-2723"
-}
-
 kotlin.sourceSets.configureEach {
     languageSettings.apiVersion = "1.4"
     languageSettings.languageVersion = "1.4"
@@ -36,69 +32,22 @@ sourcesJar()
 
 //region Setup: Backwards compatibility tests
 
-/*
-A special publication is necessary for later downloading such artifact from within this module.
-If we wanted to download a publication with the same coordinates, Gradle would always rewrite
-the dependency to a local project dependency (knowing, that the coodriantes belong to this project)
- */
-publishing {
-    publications.create<MavenPublication>("for-compatibility-tests") {
-        artifactId = "kotlin-gradle-plugin-idea-for-compatibility-tests"
-        artifact(tasks.named("jar"))
-    }
-}
-
-/* Setup Backwards Compatibility Test */
 run {
-    /* When -Pkgp-idea-snapshot is set, then the test runs against a locally installed snapshot version (./gradlew install) */
-    val isSnapshotTest = project.providers.gradleProperty("kotlin-gradle-plugin-idea.snapshot").isPresent
-
-    repositories {
-        if (isSnapshotTest) mavenLocal()
-    }
-
-    val version = if (isSnapshotTest) properties["defaultSnapshotVersion"].toString()
-    else BackwardsCompatibilityTestConfiguration.minimalBackwardsCompatibleVersion
-
-    val minimalBackwardsCompatibleVersionTestClasspath by configurations.creating {
+    val compatibilityTestClasspath by configurations.creating {
         isCanBeResolved = true
         isCanBeConsumed = false
+        attributes.attribute(Usage.USAGE_ATTRIBUTE, objects.named(Usage.JAVA_RUNTIME))
+        attributes.attribute(Category.CATEGORY_ATTRIBUTE, objects.named(Category.LIBRARY))
     }
 
     dependencies {
-        minimalBackwardsCompatibleVersionTestClasspath(
-            "org.jetbrains.kotlin:kotlin-gradle-plugin-idea-for-compatibility-tests:$version"
-        )
-
-        minimalBackwardsCompatibleVersionTestClasspath(
-            "org.jetbrains.kotlin:kotlin-stdlib:$version"
-        )
+        compatibilityTestClasspath(project(":kotlin-gradle-plugin-idea-for-compatibility-tests"))
     }
 
     tasks.test {
         dependsOnKotlinGradlePluginInstall()
-        inputs.files(minimalBackwardsCompatibleVersionTestClasspath)
-        doFirst {
-            if (isSnapshotTest) logger.quiet("Running test against snapshot: $version")
-            else logger.quiet("Running test against $version")
-
-            /*
-             Perform a check on the resolved classpath to ensure, that indeed the requested version is resolved.
-             This is a last line of defense against some unexpected Gradle resolution (like back resolving to this original project)
-             */
-            val resolvedClasspath = minimalBackwardsCompatibleVersionTestClasspath.files
-            if (resolvedClasspath.none { "kotlin-gradle-plugin-idea-for-compatibility-tests-$version.jar" in it.path }) {
-                throw IllegalStateException(buildString {
-                    appendLine("Bad backwardsCompatibilityClasspath: $resolvedClasspath")
-                    appendLine("Dependencies:${minimalBackwardsCompatibleVersionTestClasspath.allDependencies.joinToString()}")
-                })
-            }
-
-            systemProperty(
-                "backwardsCompatibilityClasspath",
-                resolvedClasspath.joinToString(";") { it.absolutePath }
-            )
-        }
+        inputs.files(compatibilityTestClasspath)
+        doFirst { systemProperty("compatibilityTestClasspath", compatibilityTestClasspath.files.joinToString(";") { it.absolutePath }) }
     }
 }
 

libraries/tools/kotlin-gradle-plugin-idea/src/test/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/BackwardsCompatibilityDeserializationTest.kt

@@ -122,11 +122,12 @@ private fun getClassLoaderForBackwardsCompatibilityTest(): ClassLoader {
 }
 
 private fun getClasspathForBackwardsCompatibilityTest(): List<File> {
-    val backwardsCompatibilityClasspathString = System.getProperty("backwardsCompatibilityClasspath")
-        ?: error("Missing backwardsCompatibilityClasspath system property")
+    val compatibilityTestClasspath = System.getProperty("compatibilityTestClasspath")
+        ?: error("Missing compatibilityTestClasspath system property")
 
-    return backwardsCompatibilityClasspathString.split(";").map { path -> File(path) }
+    return compatibilityTestClasspath.split(";").map { path -> File(path) }
         .onEach { file -> if (!file.exists()) println("[WARNING] Missing $file") }
+        .flatMap { file -> if(file.isDirectory) file.listFiles().orEmpty().toList() else listOf(file) }
 }
 
 private fun deserializeModelWithBackwardsCompatibleClasses(model: IdeaKotlinProjectModel): Any {

settings.gradle

@@ -223,6 +223,7 @@ include ":benchmarks",
         ":kotlin-project-model",
         ":kotlin-gradle-plugin-api",
         ":kotlin-gradle-plugin-idea",
+        ":kotlin-gradle-plugin-idea-for-compatibility-tests",
         ":kotlin-gradle-plugin-dsl-codegen",
         ":kotlin-gradle-plugin-npm-versions-codegen",
         ":kotlin-gradle-statistics",
@@ -669,6 +670,7 @@ project(':tools:kotlinp').projectDir = "$rootDir/libraries/tools/kotlinp" as Fil
 project(':kotlin-project-model').projectDir = "$rootDir/libraries/tools/kotlin-project-model" as File
 project(':kotlin-gradle-plugin-api').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-api" as File
 project(':kotlin-gradle-plugin-idea').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-idea" as File
+project(':kotlin-gradle-plugin-idea-for-compatibility-tests').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-idea-for-compatibility-tests" as File
 project(':kotlin-gradle-plugin-dsl-codegen').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-dsl-codegen" as File
 project(':kotlin-gradle-plugin-npm-versions-codegen').projectDir = "$rootDir/libraries/tools/kotlin-gradle-plugin-npm-versions-codegen" as File
 project(':kotlin-gradle-statistics').projectDir = "$rootDir/libraries/tools/kotlin-gradle-statistics" as File