[JS IR] Generate the correct relative paths in source maps

compiler/cli/cli-js/src/org/jetbrains/kotlin/cli/js/K2JsIrCompiler.kt

@@ -190,12 +190,9 @@ class K2JsIrCompiler : CLICompiler<K2JSCompilerArguments>() {
         val moduleName = arguments.irModuleName ?: FileUtil.getNameWithoutExtension(outputFile)
         configurationJs.put(CommonConfigurationKeys.MODULE_NAME, moduleName)
 
-        // TODO: in this method at least 3 different compiler configurations are used (original, env.configuration, jsConfig.configuration)
-        // Such situation seems a bit buggy...
-        val config = JsConfig(projectJs, configurationJs, CompilerEnvironment)
         val outputDir: File = outputFile.parentFile ?: outputFile.absoluteFile.parentFile!!
         try {
-            config.configuration.put(JSConfigurationKeys.OUTPUT_DIR, outputDir.canonicalFile)
+            configurationJs.put(JSConfigurationKeys.OUTPUT_DIR, outputDir.canonicalFile)
         } catch (e: IOException) {
             messageCollector.report(ERROR, "Could not resolve output directory", null)
             return ExitCode.COMPILATION_ERROR
@@ -262,7 +259,7 @@ class K2JsIrCompiler : CLICompiler<K2JSCompilerArguments>() {
                     configurationJs,
                     libraries,
                     friendLibraries,
-                    AnalyzerWithCompilerReport(config.configuration)
+                    AnalyzerWithCompilerReport(configurationJs)
                 )
                 val result = sourceModule.jsFrontEndResult.jsAnalysisResult
                 if (result is JsAnalysisResult.RetryWithAdditionalRoots) {

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

@@ -620,10 +620,30 @@ abstract class AbstractKotlin2JsGradlePluginIT(protected val irBackend: Boolean)
     fun testKotlinJsSourceMap(gradleVersion: GradleVersion) {
         project("kotlin2JsProjectWithSourceMap", gradleVersion) {
             build(if (irBackend) "compileDevelopmentExecutableKotlinJs" else "compileKotlinJs") {
-                val mapFilePath = projectPath
-                    .resolve("build/js/packages/$projectName-app/kotlin/$projectName-app.js.map")
+                if (irBackend) {
+                    assertFileContains(
+                        subProject("app").projectPath
+                            .resolve("build/compileSync/main/developmentExecutable/kotlin/$projectName-app.js.map"),
+                        "\"../../../../../src/main/kotlin/main.kt\"",
+                        "\"../../../../../../lib/src/main/kotlin/foo.kt\"",
+                        "\"sourcesContent\":[null",
+                    )
+                    assertFileContains(
+                        subProject("app").projectPath
+                            .resolve("build/compileSync/main/developmentExecutable/kotlin/$projectName-lib.js.map"),
+                        "\"../../../../../../lib/src/main/kotlin/foo.kt\"",
+                        "\"sourcesContent\":[null",
+                    )
+                    assertFileContains(
+                        projectPath
+                            .resolve("build/js/packages/$projectName-app/kotlin/$projectName-lib.js.map"),
+                        "\"../../../../../lib/src/main/kotlin/foo.kt\"",
+                        "\"sourcesContent\":[null",
+                    )
+                }
                 assertFileContains(
-                    mapFilePath,
+                    projectPath
+                        .resolve("build/js/packages/$projectName-app/kotlin/$projectName-app.js.map"),
                     "\"../../../../../app/src/main/kotlin/main.kt\"",
                     "\"../../../../../lib/src/main/kotlin/foo.kt\"",
                     "\"sourcesContent\":[null",
@@ -669,10 +689,6 @@ abstract class AbstractKotlin2JsGradlePluginIT(protected val irBackend: Boolean)
     }
 
     @DisplayName("path in source maps are remapped for custom outputFile")
-    @DisabledIf(
-        "org.jetbrains.kotlin.gradle.AbstractKotlin2JsGradlePluginIT#getIrBackend",
-        disabledReason = "Source maps are not supported in IR backend"
-    )
     @GradleTest
     fun testKotlinJsSourceMapCustomOutputFile(gradleVersion: GradleVersion) {
         project("kotlin2JsProjectWithSourceMap", gradleVersion) {
@@ -693,11 +709,14 @@ abstract class AbstractKotlin2JsGradlePluginIT(protected val irBackend: Boolean)
             build(if (irBackend) "compileDevelopmentExecutableKotlinJs" else "compileKotlinJs") {
                 val mapFilePath = subProject("app").projectPath
                     .resolve("build/kotlin2js/app.js.map")
-                assertFileContains(
-                    mapFilePath,
-                    "\"../../src/main/kotlin/main.kt\"",
-                    "\"../../../../../lib/src/main/kotlin/foo.kt\"",
-                )
+                assertFileContains(mapFilePath,"\"../../src/main/kotlin/main.kt\"")
+                if (irBackend) {
+                    // The IR BE generates correct paths for dependencies
+                    assertFileContains(mapFilePath, "\"../../../lib/src/main/kotlin/foo.kt\"")
+                } else {
+                    // The legacy BE doesn't.
+                    assertFileContains(mapFilePath, "\"../../../../../lib/src/main/kotlin/foo.kt\"")
+                }
             }
         }
     }

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/internal/RewriteSourceMapFilterReader.kt

@@ -141,12 +141,20 @@ open class RewriteSourceMapFilterReader(
         log.warn("Cannot rewrite paths in JavaScript source maps: $reason")
     }
 
-    protected open fun transformString(value: String): String =
-        File(srcSourceRoot)
+    protected open fun transformString(value: String): String {
+        val sourceFileResolved = File(srcSourceRoot)
             .resolve(value)
             .canonicalFile
-            .relativeToOrSelf(File(targetSourceRoot))
-            .path
+
+        val transformedPath = sourceFileResolved.relativeToOrNull(File(targetSourceRoot))?.path ?: return sourceFileResolved.path
+
+        return if (File.separatorChar == '\\') {
+            transformedPath.replace('\\', '/')
+        } else {
+            transformedPath
+        }
+    }
+
 
     override fun read(): Int {
         maybeReadFirst()

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/ir/KotlinJsIrTarget.kt

@@ -21,6 +21,7 @@ import org.jetbrains.kotlin.gradle.targets.js.KotlinJsReportAggregatingTestRun
 import org.jetbrains.kotlin.gradle.targets.js.KotlinJsTarget
 import org.jetbrains.kotlin.gradle.targets.js.binaryen.BinaryenExec
 import org.jetbrains.kotlin.gradle.targets.js.dsl.*
+import org.jetbrains.kotlin.gradle.targets.js.internal.RewriteSourceMapFilterReader
 import org.jetbrains.kotlin.gradle.targets.js.npm.npmProject
 import org.jetbrains.kotlin.gradle.tasks.locateOrRegisterTask
 import org.jetbrains.kotlin.gradle.tasks.registerTask
@@ -145,6 +146,19 @@ constructor(
 
             task.from(project.tasks.named(compilation.processResourcesTaskName))
 
+            // Rewrite relative paths in sourcemaps in the target directory
+            task.eachFile {
+                if (it.name.endsWith(".js.map")) {
+                    it.filter(
+                        mapOf(
+                            "srcSourceRoot" to it.file.parentFile,
+                            "targetSourceRoot" to npmProject.dist
+                        ),
+                        RewriteSourceMapFilterReader::class.java
+                    )
+                }
+            }
+
             task.into(npmProject.dist)
         }
     }

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/ir/KotlinJsIrTargetConfigurator.kt

@@ -128,17 +128,6 @@ open class KotlinJsIrTargetConfigurator() :
                 .all { binary ->
                     binary.linkTask.configure { linkTask ->
                         linkTask.kotlinOptions.configureOptions()
-
-                        val rootDir = binary.project.rootDir
-                        linkTask.kotlinOptions.freeCompilerArgs += listOf(
-                            "-source-map-base-dirs",
-                            rootDir.absolutePath
-                        )
-
-                        linkTask.kotlinOptions.freeCompilerArgs += listOf(
-                            "-source-map-prefix",
-                            rootDir.toRelativeString(binary.compilation.npmProject.dist) + File.separator
-                        )
                     }
                 }
         }