Kapt: Attach generated Kotlin sources in 'compilation' mode (KT-32535)

plugins/kapt3/kapt3-cli/testData/integration/kotlinFileGeneration/Test.kt

@@ -0,0 +1,19 @@
+package test
+
+import apt.Anno
+import generated.Test as TestGenerated
+
+@Anno
+class Test {
+    @field:Anno
+    val property: String = ""
+
+    @Anno
+    fun function() {
+
+    }
+}
+
+fun main() {
+    println("Generated class: " + TestGenerated::class.java.name)
+}

plugins/kapt3/kapt3-cli/testData/integration/kotlinFileGeneration/ap/META-INF/services/javax.annotation.processing.Processor

@@ -0,0 +1 @@
+apt.SampleApt

plugins/kapt3/kapt3-cli/testData/integration/kotlinFileGeneration/ap/Processor.kt

@@ -0,0 +1,37 @@
+package apt
+
+import java.io.File
+import javax.annotation.processing.*
+import javax.lang.model.SourceVersion
+import javax.lang.model.element.TypeElement
+import javax.tools.Diagnostic.Kind.*
+
+annotation class Anno
+
+class SampleApt : AbstractProcessor() {
+    private companion object {
+        const val KAPT_KOTLIN_GENERATED_OPTION_NAME = "kapt.kotlin.generated"
+    }
+
+    override fun process(annotations: Set<TypeElement>, roundEnv: RoundEnvironment): Boolean {
+        val kaptKotlinGeneratedDir = processingEnv.options[KAPT_KOTLIN_GENERATED_OPTION_NAME] ?: run {
+            processingEnv.messager.printMessage(ERROR, "Can't find the target directory for generated Kotlin files.")
+            return false
+        }
+
+        val baseDir = File(kaptKotlinGeneratedDir, "generated")
+        baseDir.mkdirs()
+
+        for (element in roundEnv.getElementsAnnotatedWith(Anno::class.java)) {
+            val generatedSimpleName = element.simpleName.toString().capitalize()
+            val file = File(baseDir, "$generatedSimpleName.kt")
+            file.writeText("package generated\nclass $generatedSimpleName")
+        }
+
+        return true
+    }
+
+    override fun getSupportedOptions() = emptySet<String>()
+    override fun getSupportedSourceVersion() = SourceVersion.RELEASE_8
+    override fun getSupportedAnnotationTypes() = setOf("apt.Anno")
+}

plugins/kapt3/kapt3-cli/testData/integration/kotlinFileGeneration/build.txt

@@ -0,0 +1,32 @@
+# mkdir
+output/ap
+output/stubs
+output/classes
+output/sources
+output/kotlin-sources
+
+# kotlinc
+-cp %KOTLIN_STDLIB%
+-d output/ap
+ap/Processor.kt
+
+# copy
+ap/META-INF/services/javax.annotation.processing.Processor
+output/ap/META-INF/services/javax.annotation.processing.Processor
+
+# kapt
+-Kapt-stubs=output/stubs
+-Kapt-classes=output/classes
+-Kapt-sources=output/sources
+-Kapt-classpath=output/ap
+-Kapt-option:kapt.kotlin.generated=output/kotlin-sources
+-d output/classes
+-cp output/ap:%KOTLIN_STDLIB%
+Test.kt
+
+# java
+-cp output/classes:output/ap:%KOTLIN_STDLIB%
+test.TestKt
+
+# after
+Generated class: generated.Test