JS DCE: drop unknown file report severity to WARNING

*.kjsm and other files might be received when FileCollection is
used in Gradle as a dependency.

Example: `testCompile project(":$coroutines_core").sourceSets.test.output`
(a popular-ish solution to introduce dependencies between tests)

compiler/cli/src/org/jetbrains/kotlin/cli/js/dce/K2JSDce.kt

@@ -33,18 +33,11 @@ class K2JSDce : CLITool<K2JSDceArguments>() {
 
     override fun execImpl(messageCollector: MessageCollector, services: Services, arguments: K2JSDceArguments): ExitCode {
         val baseDir = File(arguments.outputDirectory ?: "min")
-        var hasErrors = false
         val files = arguments.freeArgs.flatMap { arg ->
-            val files = collectInputFiles(baseDir, arg, messageCollector)
-            if (files != null) {
-                files
-            } else {
-                hasErrors = true
-                emptyList()
-            }
+            collectInputFiles(baseDir, arg, messageCollector)
         }
 
-        if (hasErrors) return ExitCode.COMPILATION_ERROR
+        if (messageCollector.hasErrors()) return ExitCode.COMPILATION_ERROR
 
         if (files.isEmpty() && !arguments.version) {
             messageCollector.report(CompilerMessageSeverity.ERROR, "no source files")
@@ -163,7 +156,7 @@ class K2JSDce : CLITool<K2JSDceArguments>() {
         return true
     }
 
-    private fun collectInputFiles(baseDir: File, fileName: String, messageCollector: MessageCollector): List<InputFile>? {
+    private fun collectInputFiles(baseDir: File, fileName: String, messageCollector: MessageCollector): List<InputFile> {
         val file = File(fileName)
         return when {
             file.isDirectory -> {
@@ -179,16 +172,16 @@ class K2JSDce : CLITool<K2JSDceArguments>() {
                     }
                     else -> {
                         messageCollector.report(
-                            CompilerMessageSeverity.ERROR,
-                            "invalid file name '$fileName'; must end either with '.js', '.zip' or '.jar'"
+                            CompilerMessageSeverity.WARNING,
+                            "invalid file name '${file.absolutePath}'; must end either with '.js', '.zip' or '.jar'"
                         )
-                        null
+                        emptyList()
                     }
                 }
             }
             else -> {
                 messageCollector.report(CompilerMessageSeverity.ERROR, "source file or directory not found: $fileName")
-                null
+                emptyList()
             }
         }
     }

compiler/testData/cli/js-dce/invalidFilename.args

@@ -0,0 +1,4 @@
+$TESTDATA_DIR$/invalidFilename.args
+$TESTDATA_DIR$/simple.js
+-output-dir
+$TEMP_DIR$/min

compiler/testData/cli/js-dce/invalidFilename.out

@@ -0,0 +1,2 @@
+warning: invalid file name '$TESTDATA_DIR$/invalidFilename.args'; must end either with '.js', '.zip' or '.jar'
+OK

compiler/testData/cli/js-dce/invalidFilename.test

@@ -0,0 +1 @@
+// EXISTS: min/simple.js

compiler/tests/org/jetbrains/kotlin/cli/CliTestGenerated.java

@@ -783,6 +783,12 @@ public class CliTestGenerated extends AbstractCliTest {
             doJsDceTest(fileName);
         }
 
+        @TestMetadata("invalidFilename.args")
+        public void testInvalidFilename() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/js-dce/invalidFilename.args");
+            doJsDceTest(fileName);
+        }
+
         @TestMetadata("jsExtraHelp.args")
         public void testJsExtraHelp() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/js-dce/jsExtraHelp.args");

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/Kotlin2JsGradlePluginIT.kt

@@ -279,6 +279,27 @@ class Kotlin2JsGradlePluginIT : BaseGradleIT() {
         }
     }
 
+    @Test
+    fun testDceFileCollectionDependency() {
+        val project = Project("kotlin2JsDceProject", "2.10", minLogLevel = LogLevel.INFO)
+
+        project.setupWorkingDir()
+        File(project.projectDir, "mainProject/build.gradle").modify {
+            it.replace("compile project(\":libraryProject\")", "compile project(\":libraryProject\").sourceSets.main.output")
+        }
+
+        project.build("runRhino") {
+            assertSuccessful()
+            val pathPrefix = "mainProject/build/kotlin-js-min/main"
+            assertFileExists("$pathPrefix/exampleapp.js.map")
+            assertFileExists("$pathPrefix/examplelib.js.map")
+            assertFileContains("$pathPrefix/exampleapp.js.map", "\"../../../src/main/kotlin/exampleapp/main.kt\"")
+
+            assertFileExists("$pathPrefix/kotlin.js")
+            assertTrue(fileInWorkingDir("$pathPrefix/kotlin.js").length() < 500 * 1000, "Looks like kotlin.js file was not minified by DCE")
+        }
+    }
+
     /** Issue: KT-18495 */
     @Test
     fun testNoSeparateClassesDirWarning() {