Test that javac is loaded once when worker is reused

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/Kapt3IT.kt

@@ -42,6 +42,20 @@ abstract class Kapt3BaseIT : BaseGradleIT() {
 class Kapt3WorkersIT : Kapt3IT() {
     override fun kaptOptions(): KaptOptions =
         super.kaptOptions().copy(useWorkers = true)
+
+    @Test
+    fun testJavacIsLoadedOnce() {
+        // todo: actual minimum version is 4.3, but I had some problems. Investigate later.
+        // todo: consider minimum version for the whole class, with Gradle <4.3 all tests duplicate tests without workers
+        val gradleVersionRequired = GradleVersionRequired.AtLeast("4.5.1")
+
+        val project =
+            Project("javacIsLoadedOnce", directoryPrefix = "kapt2", gradleVersionRequirement = gradleVersionRequired)
+        project.build("build") {
+            assertSuccessful()
+            assertSubstringCount("Loaded com.sun.tools.javac.util.Context from", 1)
+        }
+    }
 }
 
 open class Kapt3IT : Kapt3BaseIT() {

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kapt2/javacIsLoadedOnce/build.gradle

@@ -0,0 +1,16 @@
+buildscript {
+    repositories {
+        mavenLocal()
+        mavenCentral()
+    }
+    dependencies {
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+    }
+}
+
+subprojects {
+    repositories {
+        mavenLocal()
+        mavenCentral()
+    }
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kapt2/javacIsLoadedOnce/gradle.properties

@@ -0,0 +1,2 @@
+kapt.verbose=true
+kapt.workers.log.classloading=true

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kapt2/javacIsLoadedOnce/module1/build.gradle

@@ -0,0 +1,8 @@
+apply plugin: "kotlin"
+apply plugin: "kotlin-kapt"
+
+dependencies {
+    compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    compile "org.jetbrains.kotlin:annotation-processor-example:$kotlin_version"
+    kapt "org.jetbrains.kotlin:annotation-processor-example:$kotlin_version"
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kapt2/javacIsLoadedOnce/module1/src/main/kotlin/module1/Module1Class.kt

@@ -0,0 +1,12 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package module1
+
+@example.ExampleAnnotation
+class Module1Class {
+    @example.ExampleAnnotation
+    fun testFunction(): Module1ClassGenerated = Module1ClassGenerated()
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kapt2/javacIsLoadedOnce/module2/build.gradle

@@ -0,0 +1,9 @@
+apply plugin: "kotlin"
+apply plugin: "kotlin-kapt"
+
+dependencies {
+    compile project(":module1")
+    compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    compile "org.jetbrains.kotlin:annotation-processor-example:$kotlin_version"
+    kapt "org.jetbrains.kotlin:annotation-processor-example:$kotlin_version"
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kapt2/javacIsLoadedOnce/module2/src/main/kotlin/module2/Module2Class.kt

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package module2
+
+import module1.Module1Class
+
+@example.ExampleAnnotation
+class Module2Class {
+    @example.ExampleAnnotation
+    fun testFunction(): Module2ClassGenerated = Module2ClassGenerated()
+
+    fun useModule1Class(m: Module1Class) {
+        m.testFunction()
+    }
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kapt2/javacIsLoadedOnce/settings.gradle

@@ -0,0 +1 @@
+include 'module1', 'module2'

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/internal/kapt/KaptWithoutKotlincTask.kt

@@ -84,6 +84,10 @@ open class KaptWithoutKotlincTask @Inject constructor(private val workerExecutor
         workerExecutor.submit(KaptExecution::class.java) { config ->
             config.isolationMode = IsolationMode.PROCESS
             config.params(optionsForWorker, findToolsJar(), kaptClasspath)
+            if (project.findProperty("kapt.workers.log.classloading") == "true") {
+                // for tests
+                config.forkOptions.jvmArgs("-verbose:class")
+            }
             logger.info("Kapt worker classpath: ${config.classpath}")
         }