[Gradle] jvm().withJava(): Fix Zombie compilation instance returned from create()

^KT-60462 Verification Pending

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/plugin/AbstractKotlinPlugin.kt

@@ -286,4 +286,4 @@ internal abstract class AbstractKotlinPlugin(
             }
         }
     }
-}
+}

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinSourceSetProcessor.kt

@@ -15,7 +15,6 @@ import org.gradle.api.provider.Property
 import org.gradle.api.tasks.SourceSet
 import org.gradle.api.tasks.TaskProvider
 import org.gradle.api.tasks.bundling.Jar
-import org.jetbrains.kotlin.gradle.plugin.internal.JavaSourceSetsAccessor
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinJvmCompilation
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinWithJavaCompilation
 import org.jetbrains.kotlin.gradle.tasks.AbstractKotlinCompile
@@ -41,7 +40,7 @@ internal abstract class KotlinSourceSetProcessor<T : AbstractKotlinCompile<*>>(
     protected val javaSourceSet: SourceSet?
         get() = when (val compilation = compilationInfo.safeAs<KotlinCompilationInfo.TCS>()?.origin) {
             is KotlinWithJavaCompilation<*, *> -> compilation.javaSourceSet
-            is KotlinJvmCompilation -> compilation.javaSourceSet.getOrNull()
+            is KotlinJvmCompilation -> compilation.javaSourceSet
             else -> null
         }
 

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/jvm/KotlinJvmCompilation.kt

@@ -19,9 +19,6 @@ import org.jetbrains.kotlin.gradle.plugin.mpp.compilationImpl.KotlinCompilationI
 import org.jetbrains.kotlin.gradle.plugin.variantImplementationFactory
 import org.jetbrains.kotlin.gradle.targets.jvm.KotlinJvmTarget
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompilationTask
-import org.jetbrains.kotlin.gradle.utils.LenientFuture
-import org.jetbrains.kotlin.gradle.utils.future
-import org.jetbrains.kotlin.gradle.utils.lenient
 import javax.inject.Inject
 
 open class KotlinJvmCompilation @Inject internal constructor(
@@ -67,17 +64,19 @@ open class KotlinJvmCompilation @Inject internal constructor(
      * will be enabled after call to this method.
      */
     internal val compileJavaTaskProviderSafe: Provider<JavaCompile> = target.project.providers
-        .provider { javaSourceSet.getOrNull() }
+        .provider { javaSourceSet }
         .flatMap { javaSourceSet ->
-            @Suppress("RedundantRequireNotNullCall") // IDE and CLI disagree here
             checkNotNull(javaSourceSet)
             project.tasks.named(javaSourceSet.compileJavaTaskName, JavaCompile::class.java)
         }
 
-    internal val javaSourceSet: LenientFuture<SourceSet> = target.project.future {
-        target.withJavaEnabledFuture.await()
-        target.project.javaSourceSets.maybeCreate(compilationName)
-    }.lenient
+    internal val javaSourceSet
+        get() = if (target.withJavaEnabled) maybeCreateJavaSourceSet() else null
+
+    internal fun maybeCreateJavaSourceSet(): SourceSet {
+        check(target.withJavaEnabled)
+        return target.project.javaSourceSets.maybeCreate(compilationName)
+    }
 
     override val processResourcesTaskName: String
         get() = compilation.processResourcesTaskName ?: error("Missing 'processResourcesTaskName'")

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/jvm/KotlinJvmCompilationFactory.kt

@@ -6,12 +6,10 @@
 @file:Suppress("PackageDirectoryMismatch") // Old package for compatibility
 package org.jetbrains.kotlin.gradle.plugin.mpp
 
-import org.jetbrains.kotlin.gradle.plugin.*
-import org.jetbrains.kotlin.gradle.plugin.mpp.compilationImpl.*
+import org.jetbrains.kotlin.gradle.plugin.mpp.compilationImpl.KotlinJvmCompilationAssociator
 import org.jetbrains.kotlin.gradle.plugin.mpp.compilationImpl.factory.KotlinCompilationImplFactory
 import org.jetbrains.kotlin.gradle.plugin.mpp.compilationImpl.factory.KotlinJvmCompilerOptionsFactory
 import org.jetbrains.kotlin.gradle.targets.jvm.KotlinJvmTarget
-import org.jetbrains.kotlin.gradle.utils.*
 
 open class KotlinJvmCompilationFactory internal constructor(
     override val target: KotlinJvmTarget

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/jvm/KotlinJvmTarget.kt

@@ -34,9 +34,8 @@ import org.jetbrains.kotlin.gradle.targets.jvm.tasks.KotlinJvmRunDsl
 import org.jetbrains.kotlin.gradle.targets.jvm.tasks.KotlinJvmRunDslImpl
 import org.jetbrains.kotlin.gradle.targets.jvm.tasks.registerMainRunTask
 import org.jetbrains.kotlin.gradle.tasks.withType
-import org.jetbrains.kotlin.gradle.utils.*
-import org.jetbrains.kotlin.gradle.utils.CompletableFuture
 import org.jetbrains.kotlin.gradle.utils.Future
+import org.jetbrains.kotlin.gradle.utils.addExtendsFromRelation
 import org.jetbrains.kotlin.gradle.utils.findAppliedAndroidPluginIdOrNull
 import org.jetbrains.kotlin.gradle.utils.future
 import org.jetbrains.kotlin.utils.addToStdlib.cast
@@ -95,13 +94,6 @@ abstract class KotlinJvmTarget @Inject constructor(
         mainRun.await()?.configure()
     }
 
-    /**
-     * Future that will complete once [withJava] is called and java support for this target
-     * was established.
-     */
-    internal val withJavaEnabledFuture: Future<Unit> get() = withJavaEnabledFutureImpl
-    private val withJavaEnabledFutureImpl = CompletableFuture<Unit>()
-
     var withJavaEnabled = false
         private set
 
@@ -184,7 +176,9 @@ abstract class KotlinJvmTarget @Inject constructor(
             disableJavaPluginTasks(javaSourceSets)
         }
 
-        withJavaEnabledFutureImpl.complete(Unit)
+        compilations.all { compilation ->
+            compilation.maybeCreateJavaSourceSet()
+        }
     }
 
     private fun disableJavaPluginTasks(javaSourceSet: SourceSetContainer) {

libraries/tools/kotlin-gradle-plugin/src/functionalTest/kotlin/org/jetbrains/kotlin/gradle/regressionTests/KT60462WithJavaZombieCompilationTest.kt

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2010-2023 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.
+ */
+
+@file:Suppress("FunctionName")
+
+package org.jetbrains.kotlin.gradle.regressionTests
+
+import org.jetbrains.kotlin.gradle.dsl.multiplatformExtension
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinJvmCompilation
+import org.jetbrains.kotlin.gradle.util.buildProjectWithMPP
+import org.jetbrains.kotlin.gradle.util.runLifecycleAwareTest
+import kotlin.test.Test
+import kotlin.test.assertNull
+import kotlin.test.assertSame
+
+class KT60462WithJavaZombieCompilationTest {
+
+    /**
+     * Regression was introduced by:
+     *
+     * ```
+     * [Gradle] Ensure java source sets being created eagerly for 'withJava' Sebastian Sellmair* 07.07.23, 20:49
+     * 817e3de8f546e34974b89fef0f4f93b425e7e607
+     * ```
+     *
+     * The commit was ensuring that jvm compilations will create their associated java source sets
+     * as eager as possible. The solution chosen in the commit was that already the construction of the compilation
+     * will spawn a coroutine that waits for the `withJavaEnabled` callback to create the java source set.
+     *
+     * However, a buildscript like
+     *
+     * ```kotlin
+     * kotlin {
+     *     jvm().withJava()
+     *     val customCompilation = jvm().compilations.create("custom")
+     *          //    ^
+     *          //    Zombie
+     * }
+     * ```
+     *
+     * would therefore try to create the java source set right in the constructor call of the 'custom' compilation.
+     * This would have triggered a listener on `javaSourceSets.all {}` which would ensure that all
+     * java source sets have a corresponding kotlin compilation created.
+     *
+     * Since the current stack is currently inside the constructor of the first compilation, the
+     * used `compilations.maybeCreate` would trigger the creation of another custom compilation.
+     *
+     * The initial buildscript call creating the initial custom compilation will therefore return a Zombie instance
+     * ```kotlin
+     * kotlin {
+     *     val customCompilation = jvm().compilations.create("custom")
+     *     customCompilation != jvm().compilations.getByName("custom")
+     *     //    ^                                   ^
+     *     //    Zombie               Real instance created by the javaSourceSets.all listener
+     * }
+     * ```
+     */
+    @Test
+    fun `test - custom compilation`() = buildProjectWithMPP().runLifecycleAwareTest {
+        multiplatformExtension.jvm().apply {
+            withJava()
+
+            var instanceUsedForConfigureBlock: KotlinJvmCompilation? = null
+
+            val instanceReturnedFromCreate = compilations.create("custom") { instance ->
+                assertNull(instanceUsedForConfigureBlock)
+                instanceUsedForConfigureBlock = instance
+            }
+
+            val instanceReturnedFromGet = compilations.getByName("custom")
+
+            assertSame(instanceReturnedFromCreate, instanceUsedForConfigureBlock)
+            assertSame(instanceReturnedFromGet, instanceUsedForConfigureBlock)
+        }
+    }
+}