Filter out non-Java files from kapt inputs

#KT-23878 fixed

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

@@ -9,7 +9,23 @@ import org.junit.Test
 class KaptIncrementalNoStubsIT : KaptIncrementalBaseIT(shouldUseStubs = false)
 class KaptIncrementalWithStubsIT : KaptIncrementalBaseIT(shouldUseStubs = true)
 
-class Kapt3Incremental : KaptIncrementalBaseIT(shouldUseStubs = false, useKapt3 = true)
+class Kapt3Incremental : KaptIncrementalBaseIT(shouldUseStubs = false, useKapt3 = true) {
+    @Test
+    fun testAddNewLine() {
+        val project = Project("simple", directoryPrefix = "kapt2")
+
+        project.build("clean", "build") {
+            assertSuccessful()
+        }
+
+        project.projectFile("test.kt").modify { "\n$it" }
+        project.build("build") {
+            assertSuccessful()
+            assertTasksExecuted(":kaptGenerateStubsKotlin", ":compileJava", ":compileKotlin")
+            assertTasksUpToDate(":kaptKotlin")
+        }
+    }
+}
 
 abstract class KaptIncrementalBaseIT(val shouldUseStubs: Boolean, val useKapt3: Boolean = false) : BaseGradleIT() {
     init {
@@ -277,10 +293,7 @@ abstract class KaptIncrementalBaseIT(val shouldUseStubs: Boolean, val useKapt3:
 
     private fun CompiledProject.assertKapt3FullyExecuted() {
         if (useKapt3) {
-            assertNotContains(
-                ":kaptKotlin UP-TO-DATE",
-                ":kaptGenerateStubsKotlin UP-TO-DATE"
-            )
+            assertTasksExecuted(":kaptKotlin", ":kaptGenerateStubsKotlin")
         }
     }
 

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

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.compilerRunner.GradleCompilerEnvironment
 import org.jetbrains.kotlin.compilerRunner.GradleCompilerRunner
 import org.jetbrains.kotlin.compilerRunner.OutputItemsCollectorImpl
 import org.jetbrains.kotlin.gradle.tasks.*
+import org.jetbrains.kotlin.incremental.isJavaFile
 import java.io.File
 
 @CacheableTask
@@ -36,11 +37,6 @@ open class KaptTask : ConventionTask(), CompilerArgumentAwareWithInput<K2JVMComp
     @get:Internal
     internal lateinit var stubsDir: File
 
-    private fun isInsideDestinationDirs(file: File): Boolean {
-        return FileUtil.isAncestor(destinationDir, file, /* strict = */ false)
-                || FileUtil.isAncestor(classesDir, file, /* strict = */ false)
-    }
-
     @get:Classpath @get:InputFiles
     val kaptClasspath: FileCollection
         get() = project.files(*kaptClasspathConfigurations.toTypedArray())
@@ -87,25 +83,29 @@ open class KaptTask : ConventionTask(), CompilerArgumentAwareWithInput<K2JVMComp
     internal val pluginClasspath get() = pluginOptions.classpath
 
     @get:InputFiles @get:PathSensitive(PathSensitivity.RELATIVE)
-    val source: FileCollection
+    val source: Collection<File>
         get() {
-            val sourcesFromKotlinTask = kotlinCompileTask.source
-                    .filter { it.extension == "java" && !isInsideDestinationDirs(it) }
-
-            val stubSources = project.fileTree(stubsDir)
-            return sourcesFromKotlinTask + stubSources
+            val result = HashSet<File>()
+            for (root in javaSourceRoots) {
+                root.walk().filterTo(result) { it.isJavaFile() }
+            }
+            return result
         }
 
+    private val javaSourceRoots: Set<File>
+        get() = (kotlinCompileTask.sourceRootsContainer.sourceRoots + stubsDir)
+            .filterTo(HashSet(), ::isRootAllowed)
+
+    private fun isRootAllowed(file: File): Boolean =
+        !FileUtil.isAncestor(destinationDir, file, /* strict = */ false) &&
+                !FileUtil.isAncestor(classesDir, file, /* strict = */ false)
+
     @TaskAction
     fun compile() {
         /** Delete everything inside generated sources and classes output directory
          * (annotation processing is not incremental) */
         clearOutputDirectories()
 
-        val sourceRootsFromKotlin = kotlinCompileTask.sourceRootsContainer.sourceRoots
-        val rawSourceRoots = FilteringSourceRootsContainer(sourceRootsFromKotlin, { !isInsideDestinationDirs(it) })
-        val sourceRoots = SourceRoots.ForJvm.create(kotlinCompileTask.source, rawSourceRoots)
-
         val args = prepareCompilerArguments()
 
         val messageCollector = GradleMessageCollector(logger)
@@ -117,11 +117,12 @@ open class KaptTask : ConventionTask(), CompilerArgumentAwareWithInput<K2JVMComp
 
         val compilerRunner = GradleCompilerRunner(project)
         val exitCode = compilerRunner.runJvmCompiler(
-                sourceRoots.kotlinSourceFiles,
-                sourceRoots.javaSourceRoots,
-                kotlinCompileTask.javaPackagePrefix,
-                args,
-                environment)
+            sourcesToCompile = emptyList(),
+            javaSourceRoots = javaSourceRoots,
+            javaPackagePrefix = kotlinCompileTask.javaPackagePrefix,
+            args = args,
+            environment = environment
+        )
         throwGradleExceptionIfError(exitCode)
     }