[JS DCE] Add an ability to define overwriting strategy when copying dependencies in dev-mode

* CLI option "-Xdev-mode-overwriting-strategy"
* System Property "kotlin.js.dce.devmode.overwriting.strategy"

Possible values: "older", "all".

#KT-36349 Fixed

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JSDceArguments.kt

@@ -1,21 +1,13 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2010-2020 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.
  */
 
 package org.jetbrains.kotlin.cli.common.arguments
 
+import org.jetbrains.kotlin.cli.common.arguments.DevModeOverwritingStrategies.ALL
+import org.jetbrains.kotlin.cli.common.arguments.DevModeOverwritingStrategies.OLDER
+
 class K2JSDceArguments : CommonToolArguments() {
     companion object {
         @JvmStatic private val serialVersionUID = 0L
@@ -48,4 +40,16 @@ class K2JSDceArguments : CommonToolArguments() {
     )
     @GradleOption(DefaultValues.BooleanFalseDefault::class)
     var devMode: Boolean by FreezableVar(false)
+
+    @Argument(
+        value = "-Xdev-mode-overwriting-strategy",
+        valueDescription = "{$OLDER|$ALL}",
+        description = "Overwriting strategy during copy dependencies in development mode"
+    )
+    var devModeOverwritingStrategy: String? by NullableStringFreezableVar(null)
+}
+
+object DevModeOverwritingStrategies {
+    const val OLDER = "older"
+    const val ALL = "all"
 }

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

@@ -1,23 +1,13 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2010-2020 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.
  */
 
 package org.jetbrains.kotlin.cli.js.dce
 
 import org.jetbrains.kotlin.cli.common.CLITool
 import org.jetbrains.kotlin.cli.common.ExitCode
+import org.jetbrains.kotlin.cli.common.arguments.DevModeOverwritingStrategies
 import org.jetbrains.kotlin.cli.common.arguments.K2JSDceArguments
 import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity
 import org.jetbrains.kotlin.cli.common.messages.MessageCollector
@@ -63,7 +53,13 @@ class K2JSDce : CLITool<K2JSDceArguments>() {
         return if (!arguments.devMode) {
             performDce(files, arguments, messageCollector)
         } else {
-            copyFiles(files)
+            val devModeOverwritingStrategy =
+                arguments.devModeOverwritingStrategy ?:
+                System.getProperty("kotlin.js.dce.devmode.overwriting.strategy", DevModeOverwritingStrategies.OLDER)
+
+            val overwriteOnlyOlderFiles = devModeOverwritingStrategy == DevModeOverwritingStrategies.OLDER
+
+            copyFiles(files, overwriteOnlyOlderFiles)
             ExitCode.OK
         }
     }
@@ -96,21 +92,22 @@ class K2JSDce : CLITool<K2JSDceArguments>() {
         return ExitCode.OK
     }
 
-    private fun copyFiles(files: List<InputFile>) {
+    private fun copyFiles(files: List<InputFile>, overwriteOnlyOlderFiles: Boolean) {
         for (file in files) {
-            copyResource(file.resource, File(file.outputPath))
+            copyResource(file.resource, File(file.outputPath), overwriteOnlyOlderFiles)
             file.sourceMapResource?.let { sourceMap ->
                 val sourceMapTarget = File(file.outputPath + ".map")
                 val inputFile = File(sourceMap.name)
                 if (!inputFile.exists() || !mapSourcePaths(inputFile, sourceMapTarget)) {
-                    copyResource(sourceMap, sourceMapTarget)
+                    copyResource(sourceMap, sourceMapTarget, overwriteOnlyOlderFiles)
                 }
             }
         }
     }
 
-    private fun copyResource(resource: InputResource, targetFile: File) {
-        if (targetFile.exists() && resource.lastModified() < targetFile.lastModified()) return
+    private fun copyResource(resource: InputResource, targetFile: File, overwriteOnlyOlderFiles: Boolean) {
+        // TODO shouldn't it be "<="?
+        if (overwriteOnlyOlderFiles && targetFile.exists() && resource.lastModified() < targetFile.lastModified()) return
 
         targetFile.parentFile.mkdirs()
         resource.reader().use { input ->

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

@@ -1,5 +1,7 @@
 Usage: kotlin-dce-js <options> <source files>
 where advanced options include:
+  -Xdev-mode-overwriting-strategy={older|all}
+                             Overwriting strategy during copy dependencies in development mode
   -Xprint-reachability-info  Print declarations marked as reachable
 
 Advanced options are non-standard and may be changed or removed without any notice.

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

@@ -976,6 +976,11 @@ public class CliTestGenerated extends AbstractCliTest {
             KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/cli/js-dce"), Pattern.compile("^(.+)\\.args$"), null, false);
         }
 
+        @TestMetadata("dceExtraHelp.args")
+        public void testDceExtraHelp() throws Exception {
+            runTest("compiler/testData/cli/js-dce/dceExtraHelp.args");
+        }
+
         @TestMetadata("dceHelp.args")
         public void testDceHelp() throws Exception {
             runTest("compiler/testData/cli/js-dce/dceHelp.args");
@@ -996,11 +1001,6 @@ public class CliTestGenerated extends AbstractCliTest {
             runTest("compiler/testData/cli/js-dce/invalidFilename.args");
         }
 
-        @TestMetadata("jsExtraHelp.args")
-        public void testJsExtraHelp() throws Exception {
-            runTest("compiler/testData/cli/js-dce/jsExtraHelp.args");
-        }
-
         @TestMetadata("nonExistingSourcePath.args")
         public void testNonExistingSourcePath() throws Exception {
             runTest("compiler/testData/cli/js-dce/nonExistingSourcePath.args");