[JS IR] Append source mapping URL every time on writing JS code

Source mapping URL is not saved in JS module cache anymore,
 because it was a wrong url pointed to the source map from the cache.
 Instead, the URL is appended every time on writing the output JS code.

^KT-56469 Fixed

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/ic/JsMultiModuleCache.kt

@@ -96,19 +96,18 @@ class JsMultiModuleCache(private val moduleArtifacts: List<ModuleArtifact>) {
     }
 
     fun fetchCompiledJsCode(artifact: ModuleArtifact) = artifact.artifactsDir?.let { cacheDir ->
-        val jsCodeFilePath = File(cacheDir, CACHED_MODULE_JS).ifExists { absolutePath }
+        val jsCodeFile = File(cacheDir, CACHED_MODULE_JS).ifExists { this }
-        val sourceMapFilePath = File(cacheDir, CACHED_MODULE_JS_MAP).ifExists { absolutePath }
+        val sourceMapFile = File(cacheDir, CACHED_MODULE_JS_MAP).ifExists { this }
-        val tsDefinitionsFilePath = File(cacheDir, CACHED_MODULE_D_TS).ifExists { absolutePath }
+        val tsDefinitionsFile = File(cacheDir, CACHED_MODULE_D_TS).ifExists { this }
-        jsCodeFilePath?.let { CompilationOutputsCached(it, sourceMapFilePath, tsDefinitionsFilePath) }
+        jsCodeFile?.let { CompilationOutputsCached(it, sourceMapFile, tsDefinitionsFile) }
     }
 
     fun commitCompiledJsCode(artifact: ModuleArtifact, compilationOutputs: CompilationOutputsBuilt): CompilationOutputs =
         artifact.artifactsDir?.let { cacheDir ->
             val jsCodeFile = File(cacheDir, CACHED_MODULE_JS)
             val jsMapFile = File(cacheDir, CACHED_MODULE_JS_MAP)
-            compilationOutputs.writeJsCode(jsCodeFile, jsMapFile)
             File(cacheDir, CACHED_MODULE_D_TS).writeIfNotNull(compilationOutputs.tsDefinitions?.raw)
-            CompilationOutputsBuiltForCache(jsCodeFile.absolutePath, jsMapFile.absolutePath, compilationOutputs)
+            compilationOutputs.writeJsCodeIntoModuleCache(jsCodeFile, jsMapFile)
         } ?: compilationOutputs
 
     fun loadProgramHeadersFromCache(): List<CachedModuleInfo> {

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/CompilationOutputs.kt

@@ -64,23 +64,6 @@ abstract class CompilationOutputs {
         get() = resolveSibling("$nameWithoutExtension.d.ts").canonicalFile
 }
 
-class CompilationOutputsBuilt(
-    private val rawJsCode: String,
-    private val sourceMap: String?,
-    override val tsDefinitions: TypeScriptFragment?,
-    override val jsProgram: JsProgram?,
-) : CompilationOutputs() {
-    override fun writeJsCode(outputJsFile: File, outputJsMapFile: File) {
-        var jsCodeWithSourceMap = rawJsCode
-
-        sourceMap?.let {
-            outputJsMapFile.writeText(it)
-            jsCodeWithSourceMap = "$jsCodeWithSourceMap\n//# sourceMappingURL=${outputJsMapFile.name}\n"
-        }
-        outputJsFile.writeText(jsCodeWithSourceMap)
-    }
-}
-
 private fun File.copyModificationTimeFrom(from: File) {
     val mtime = from.lastModified()
     if (mtime > 0) {
@@ -88,38 +71,67 @@ private fun File.copyModificationTimeFrom(from: File) {
     }
 }
 
+private fun File.asSourceMappingUrl(): String {
+    return "\n//# sourceMappingURL=${name}\n"
+}
+
+class CompilationOutputsBuilt(
+    private val rawJsCode: String,
+    private val sourceMap: String?,
+    override val tsDefinitions: TypeScriptFragment?,
+    override val jsProgram: JsProgram?,
+) : CompilationOutputs() {
+    override fun writeJsCode(outputJsFile: File, outputJsMapFile: File) {
+        val sourceMappingUrl = sourceMap?.let {
+            outputJsMapFile.writeText(it)
+            outputJsMapFile.asSourceMappingUrl()
+        } ?: ""
+        outputJsFile.writeText(rawJsCode + sourceMappingUrl)
+    }
+
+    fun writeJsCodeIntoModuleCache(outputJsFile: File, outputJsMapFile: File): CompilationOutputsBuiltForCache {
+        sourceMap?.let { outputJsMapFile.writeText(it) }
+        outputJsFile.writeText(rawJsCode)
+        return CompilationOutputsBuiltForCache(outputJsFile, outputJsMapFile, this)
+    }
+}
+
 class CompilationOutputsCached(
-    private val jsCodeFilePath: String,
+    private val jsCodeFile: File,
-    private val sourceMapFilePath: String?,
+    private val sourceMapFile: File?,
-    private val tsDefinitionsFilePath: String?
+    private val tsDefinitionsFile: File?
 ) : CompilationOutputs() {
     override val tsDefinitions: TypeScriptFragment?
-        get() = tsDefinitionsFilePath?.let { TypeScriptFragment(File(it).readText()) }
+        get() = tsDefinitionsFile?.let { TypeScriptFragment(it.readText()) }
 
     override val jsProgram: JsProgram?
         get() = null
 
     override fun writeJsCode(outputJsFile: File, outputJsMapFile: File) {
-        File(jsCodeFilePath).copyToIfModified(outputJsFile)
+        val sourceMappingUrl = sourceMapFile?.let {
+            if (it.isUpdateRequired(outputJsMapFile)) {
+                it.copyTo(outputJsMapFile, true)
+                it.copyModificationTimeFrom(outputJsMapFile)
+            }
+            outputJsMapFile.asSourceMappingUrl()
+        } ?: ""
 
-        sourceMapFilePath?.let {
+        if (jsCodeFile.isUpdateRequired(outputJsFile)) {
-            File(it).copyToIfModified(outputJsMapFile)
+            outputJsFile.writeText(jsCodeFile.readText() + sourceMappingUrl)
+            jsCodeFile.copyModificationTimeFrom(outputJsFile)
         }
     }
 
-    private fun File.copyToIfModified(target: File) {
+    private fun File.isUpdateRequired(target: File): Boolean {
         val thisMtime = lastModified()
         val targetMtime = target.lastModified()
-        if (thisMtime <= 0 || targetMtime <= 0 || targetMtime > thisMtime) {
+        return thisMtime <= 0 || targetMtime <= 0 || targetMtime > thisMtime
-            copyTo(target, true)
-            copyModificationTimeFrom(target)
-        }
     }
 }
 
 class CompilationOutputsBuiltForCache(
-    private val jsCodeFilePath: String,
+    private val jsCodeFile: File,
-    private val sourceMapFilePath: String,
+    private val sourceMapFile: File,
     private val outputBuilt: CompilationOutputsBuilt
 ) : CompilationOutputs() {
 
@@ -136,7 +148,7 @@ class CompilationOutputsBuiltForCache(
     override fun writeJsCode(outputJsFile: File, outputJsMapFile: File) {
         outputBuilt.writeJsCode(outputJsFile, outputJsMapFile)
 
-        File(jsCodeFilePath).copyModificationTimeFrom(outputJsFile)
+        jsCodeFile.copyModificationTimeFrom(outputJsFile)
-        File(sourceMapFilePath).copyModificationTimeFrom(outputJsMapFile)
+        sourceMapFile.copyModificationTimeFrom(outputJsMapFile)
     }
 }

js/js.tests/test/org/jetbrains/kotlin/incremental/AbstractInvalidationTest.kt

@@ -65,6 +65,8 @@ abstract class AbstractInvalidationTest(
         private val TEST_FILE_IGNORE_PATTERN = Regex("^.*\\..+\\.\\w\\w$")
 
         private val JS_MODULE_KIND = ModuleKind.COMMON_JS
+
+        private const val SOURCE_MAPPING_URL_PREFIX = "//# sourceMappingURL="
     }
 
     override fun createEnvironment(): KotlinCoreEnvironment {
@@ -117,6 +119,7 @@ abstract class AbstractInvalidationTest(
         copy.put(JSConfigurationKeys.GENERATE_DTS, true)
         copy.put(JSConfigurationKeys.MODULE_KIND, JS_MODULE_KIND)
         copy.put(JSConfigurationKeys.PROPERTY_LAZY_INITIALIZATION, true)
+        copy.put(JSConfigurationKeys.SOURCE_MAP, true)
 
         copy.languageVersionSettings = with(LanguageVersionSettingsBuilder()) {
             language.forEach {
@@ -246,7 +249,6 @@ abstract class AbstractInvalidationTest(
             }
         }
 
-
         private fun verifyJsCode(stepId: Int, mainModuleName: String, jsFiles: List<String>) {
             try {
                 V8IrJsTestChecker.checkWithTestFunctionArgs(
@@ -293,11 +295,16 @@ abstract class AbstractInvalidationTest(
             )
         }
 
-        private fun writeJsCode(mainModuleName: String, jsOutput: CompilationOutputs): List<String> {
+        private fun writeJsCode(stepId: Int, mainModuleName: String, jsOutput: CompilationOutputs): List<String> {
             val compiledJsFiles = jsOutput.writeAll(jsDir, mainModuleName, true, mainModuleName, JS_MODULE_KIND).filter {
                 it.extension == "js"
             }
             for (jsCodeFile in compiledJsFiles) {
+                val sourceMappingUrlLine = jsCodeFile.readLines().singleOrNull { it.startsWith(SOURCE_MAPPING_URL_PREFIX) }
+                JUnit4Assertions.assertEquals("$SOURCE_MAPPING_URL_PREFIX${jsCodeFile.name}.map", sourceMappingUrlLine) {
+                    "Mismatched source map url at step $stepId"
+                }
+
                 jsCodeFile.writeAsJsModule(jsCodeFile.readText(), "./${jsCodeFile.name}")
             }
 
@@ -349,7 +356,7 @@ abstract class AbstractInvalidationTest(
                 )
 
                 val (jsOutput, rebuiltModules) = jsExecutableProducer.buildExecutable(multiModule = true, outJsProgram = true)
-                val writtenFiles = writeJsCode(mainModuleName, jsOutput)
+                val writtenFiles = writeJsCode(projStep.id, mainModuleName, jsOutput)
 
                 verifyJsExecutableProducerBuildModules(projStep.id, rebuiltModules, projStep.dirtyJS)
                 verifyJsCode(projStep.id, mainModuleName, writtenFiles)