Provide compiler classpath as task input.

This ensures that compiler classpath is what is expected
by Kotlin Plugin and removes possibility of leaking wrong jars
from Gradle wrapper classpath.

For 'kotlin.useFallbackCompilerSearch' old behaviour is still present,
but this option should be marked as deprecated and removed in one
of the Kotlin releases.

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

@@ -20,6 +20,7 @@ import org.jetbrains.kotlin.compilerRunner.*
 import org.junit.Assert
 import org.junit.Test
 import java.io.File
+import kotlin.test.assertTrue
 
 // todo: test client file creation/deletion
 // todo: test daemon start (does not start every build)
@@ -91,4 +92,43 @@ class KotlinDaemonIT : BaseGradleIT() {
             }
         }
     }
+
+    @Test
+    fun testGradleBuildClasspathShouldNotBeLeakedIntoDaemonClasspath() {
+        val testProject = Project("kotlinProject")
+        testProject.setupWorkingDir()
+
+        testProject.build("assemble") {
+            assertGradleClasspathNotLeaked()
+        }
+    }
+
+    @Test
+    fun testGradleBuildClasspathShouldNotBeLeakedIntoDaemonClasspathOnUsingCustomCompilerJar() {
+        val testProject = Project(
+            projectName = "customCompilerFile",
+        )
+        testProject.setupWorkingDir()
+
+        // copy compiler embeddable into project dir using custom name
+        val classpath = System.getProperty("java.class.path").split(File.pathSeparator)
+        val kotlinEmbeddableJar = File(classpath.find { it.contains("kotlin-compiler-embeddable") }!!)
+
+        val compilerJar = File(testProject.projectDir, "compiler.jar")
+        kotlinEmbeddableJar.copyTo(compilerJar)
+
+        testProject.build("build") {
+            assertGradleClasspathNotLeaked()
+        }
+    }
+
+    private fun CompiledProject.assertGradleClasspathNotLeaked() {
+        assertContains("Kotlin compiler classpath:")
+        val daemonClasspath = output.lineSequence().find {
+            it.contains("Kotlin compiler classpath:")
+        }!!
+        assertTrue("Daemon classpath contains embeddable daemon jar leaked from Gradle dist classpath: $daemonClasspath") {
+            !daemonClasspath.contains(".gradle/wrapper/dists")
+        }
+    }
 }

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

@@ -21,10 +21,8 @@ import org.gradle.api.NamedDomainObjectFactory
 import org.gradle.api.Plugin
 import org.gradle.api.Project
 import org.gradle.api.internal.FeaturePreviews
-import org.gradle.api.internal.file.FileResolver
 import org.gradle.api.logging.Logger
 import org.gradle.api.logging.Logging
-import org.gradle.build.event.BuildEventsListenerRegistry
 import org.gradle.tooling.provider.model.ToolingModelBuilderRegistry
 import org.jetbrains.kotlin.gradle.dsl.*
 import org.jetbrains.kotlin.gradle.logging.kotlinDebug
@@ -36,10 +34,10 @@ import org.jetbrains.kotlin.gradle.plugin.statistics.KotlinBuildStatsService
 import org.jetbrains.kotlin.gradle.targets.js.KotlinJsCompilerAttribute
 import org.jetbrains.kotlin.gradle.targets.js.KotlinJsPlugin
 import org.jetbrains.kotlin.gradle.targets.js.npm.addNpmDependencyExtension
+import org.jetbrains.kotlin.gradle.tasks.*
 import org.jetbrains.kotlin.gradle.tasks.KOTLIN_COMPILER_EMBEDDABLE
 import org.jetbrains.kotlin.gradle.tasks.KOTLIN_KLIB_COMMONIZER_EMBEDDABLE
 import org.jetbrains.kotlin.gradle.tasks.KOTLIN_MODULE_GROUP
-import org.jetbrains.kotlin.gradle.tasks.throwGradleExceptionIfError
 import org.jetbrains.kotlin.gradle.testing.internal.KotlinTestsRegistry
 import org.jetbrains.kotlin.gradle.utils.checkGradleCompatibility
 import org.jetbrains.kotlin.gradle.utils.loadPropertyFromResources
@@ -68,9 +66,8 @@ abstract class KotlinBasePluginWrapper : Plugin<Project> {
             whenBuildEvaluated(project)
         }
 
-        project.configurations.maybeCreate(COMPILER_CLASSPATH_CONFIGURATION_NAME).defaultDependencies {
+        addKotlinCompilerConfiguration(project)
-            it.add(project.dependencies.create("$KOTLIN_MODULE_GROUP:$KOTLIN_COMPILER_EMBEDDABLE:$kotlinPluginVersion"))
+
-        }
         project.configurations.maybeCreate(PLUGIN_CLASSPATH_CONFIGURATION_NAME)
         project.configurations.maybeCreate(NATIVE_COMPILER_PLUGIN_CLASSPATH_CONFIGURATION_NAME).apply {
             isTransitive = false
@@ -106,6 +103,25 @@ abstract class KotlinBasePluginWrapper : Plugin<Project> {
         project.addNpmDependencyExtension()
     }
 
+    private fun addKotlinCompilerConfiguration(project: Project) {
+        project
+            .configurations
+            .maybeCreate(COMPILER_CLASSPATH_CONFIGURATION_NAME)
+            .defaultDependencies {
+                it.add(
+                    project.dependencies.create("$KOTLIN_MODULE_GROUP:$KOTLIN_COMPILER_EMBEDDABLE:$kotlinPluginVersion")
+                )
+            }
+        project
+            .tasks
+            .withType(AbstractKotlinCompile::class.java)
+            .configureEach { task ->
+                task.defaultCompilerClasspath.setFrom(
+                    project.configurations.named(COMPILER_CLASSPATH_CONFIGURATION_NAME)
+                )
+            }
+    }
+
     open fun whenBuildEvaluated(project: Project) {
     }
 

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/KotlinJsDcePlugin.kt

@@ -64,6 +64,7 @@ class KotlinJsDcePlugin : Plugin<Project> {
 
         val dceTask = project.registerTask<KotlinJsDce>(dceTaskName) {
             it.dependsOn(kotlinTask)
+            it.defaultCompilerClasspath.setFrom(project.configurations.named(COMPILER_CLASSPATH_CONFIGURATION_NAME))
         }
         project.tasks.named("build").dependsOn(dceTask)
 

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/subtargets/KotlinBrowserJs.kt

@@ -10,6 +10,7 @@ import org.gradle.api.tasks.Copy
 import org.gradle.api.tasks.TaskProvider
 import org.gradle.language.base.plugins.LifecycleBasePlugin
 import org.jetbrains.kotlin.gradle.dsl.KotlinJsDce
+import org.jetbrains.kotlin.gradle.plugin.COMPILER_CLASSPATH_CONFIGURATION_NAME
 import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinJsCompilation
 import org.jetbrains.kotlin.gradle.targets.js.KotlinJsTarget
@@ -287,6 +288,7 @@ open class KotlinBrowserJs @Inject constructor(target: KotlinJsTarget) :
             it.classpath = project.configurations.getByName(compilation.runtimeDependencyConfigurationName)
             it.destinationDir = it.dceOptions.outputDirectory?.let { File(it) }
                 ?: compilation.npmProject.dir.resolve(if (dev) DCE_DEV_DIR else DCE_DIR)
+            it.defaultCompilerClasspath.setFrom(project.configurations.named(COMPILER_CLASSPATH_CONFIGURATION_NAME))
 
             it.source(kotlinTask.map { it.outputFile })
         }

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

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.gradle.tasks
 
 import org.gradle.api.Project
 import org.gradle.api.Task
+import org.gradle.api.file.ConfigurableFileCollection
 import org.gradle.api.file.FileCollection
 import org.gradle.api.logging.Logger
 import org.gradle.api.provider.Provider
@@ -98,28 +99,32 @@ abstract class AbstractKotlinCompileTool<T : CommonToolArguments>
     override val metrics: BuildMetricsReporter =
         BuildMetricsReporterImpl()
 
+    /**
+     * By default should be set by plugin from [COMPILER_CLASSPATH_CONFIGURATION_NAME] configuration.
+     *
+     * Empty classpath will fail the build.
+     */
+    @get:Classpath
+    internal val defaultCompilerClasspath: ConfigurableFileCollection =
+        project.objects.fileCollection()
+
     @get:Classpath
     @get:InputFiles
     internal val computedCompilerClasspath: List<File> by lazy {
-        compilerClasspath?.takeIf { it.isNotEmpty() }
+        require(!defaultCompilerClasspath.isEmpty) {
-            ?: compilerJarFile?.let {
+            "Default Kotlin compiler classpath is empty! Task: ${this::class.qualifiedName}"
-                // a hack to remove compiler jar from the cp, will be dropped when compilerJarFile will be removed
+        }
-                listOf(it) + findKotlinCompilerClasspath(project).filter { !it.name.startsWith("kotlin-compiler") }
+
-            }
+        when {
-            ?: if (!useFallbackCompilerSearch) {
+            !compilerClasspath.isNullOrEmpty() -> compilerClasspath!!
-                try {
+            compilerJarFile != null -> listOf(compilerJarFile!!) +
-                    project.configurations.getByName(COMPILER_CLASSPATH_CONFIGURATION_NAME).resolve().toList()
+                    defaultCompilerClasspath
-                } catch (e: Exception) {
+                        .filterNot {
-                    logger.error(
+                            it.nameWithoutExtension.startsWith("kotlin-compiler")
-                        "Could not resolve compiler classpath. " +
+                        }
-                                "Check if Kotlin Gradle plugin repository is configured in $project."
+            useFallbackCompilerSearch -> findKotlinCompilerClasspath(project)
-                    )
+            else -> defaultCompilerClasspath.toList()
-                    throw e
+        }
-                }
-            } else {
-                findKotlinCompilerClasspath(project)
-            }
-            ?: throw IllegalStateException("Could not find Kotlin Compiler classpath")
     }