[JS] Support the 'names' field in sourcemaps

js/js.parser/src/org/jetbrains/kotlin/js/parser/sourcemaps/SourceMap.kt

@@ -28,7 +28,8 @@ class SourceMap(val sourceContentResolver: (String) -> Reader?) {
         for ((index, group) in groups.withIndex()) {
             writer.print("${index + 1}:")
             for (segment in group.segments) {
-                writer.print(" ${segment.generatedColumnNumber + 1}:${segment.sourceLineNumber + 1},${segment.sourceColumnNumber + 1}")
+                val nameIfPresent = if (segment.name != null) "(${segment.name})" else ""
+                writer.print(" ${segment.generatedColumnNumber + 1}:${segment.sourceLineNumber + 1},${segment.sourceColumnNumber + 1}$nameIfPresent")
             }
             writer.println()
         }
@@ -42,8 +43,9 @@ class SourceMap(val sourceContentResolver: (String) -> Reader?) {
             val generatedLine = generatedLines[index]
             val segmentsByColumn = group.segments.map { it.generatedColumnNumber to it }.toMap()
             for (i in generatedLine.indices) {
-                segmentsByColumn[i]?.let { (_, sourceFile, sourceLine, sourceColumn) ->
-                    writer.print("<$sourceFile:${sourceLine + 1}:${sourceColumn + 1}>")
+                segmentsByColumn[i]?.let { (_, sourceFile, sourceLine, sourceColumn, name) ->
+                    val nameIfPresent = if (name != null) "($name)" else ""
+                    writer.print("<$sourceFile:${sourceLine + 1}:${sourceColumn + 1}$nameIfPresent>")
                 }
                 writer.print(generatedLine[i])
             }
@@ -96,7 +98,8 @@ data class SourceMapSegment(
     val generatedColumnNumber: Int,
     val sourceFileName: String?,
     val sourceLineNumber: Int,
-    val sourceColumnNumber: Int
+    val sourceColumnNumber: Int,
+    val name: String?,
 )
 
 class SourceMapGroup {

js/js.parser/src/org/jetbrains/kotlin/js/parser/sourcemaps/SourceMapLocationRemapper.kt

@@ -70,10 +70,10 @@ class SourceMapLocationRemapper(private val sourceMap: SourceMap, private val so
             val segment = findCorrespondingSegment(node)
             val sourceFileName = segment?.sourceFileName
             node.source = if (sourceFileName != null) {
-                val location = JsLocation(sourceMapPathMapper(sourceFileName), segment.sourceLineNumber, segment.sourceColumnNumber)
+                val location =
+                    JsLocation(sourceMapPathMapper(sourceFileName), segment.sourceLineNumber, segment.sourceColumnNumber, segment.name)
                 JsLocationWithEmbeddedSource(location, null) { sourceMap.sourceContentResolver(segment.sourceFileName) }
-            }
-            else {
+            } else {
                 null
             }
         }

js/js.parser/src/org/jetbrains/kotlin/js/parser/sourcemaps/SourceMapParser.kt

@@ -86,6 +86,17 @@ object SourceMapParser {
             }
         }
 
+        val names = jsonObject.properties["names"].let {
+            if (it != null) {
+                val namesProperty = it as? JsonArray ?: return SourceMapError("'names' property is not of array type")
+                namesProperty.elements.map {
+                    (it as? JsonString ?: return SourceMapError("'names' array must contain strings")).value
+                }
+            } else {
+                emptyList()
+            }
+        }
+
         val sourcePathToContent = sources.zip(sourcesContent).associate { it }
 
         val mappings = jsonObject.properties["mappings"] ?: return SourceMapError("'mappings' property not found")
@@ -95,6 +106,7 @@ object SourceMapParser {
         var sourceLine = 0
         var sourceColumn = 0
         var sourceIndex = 0
+        var nameIndex = 0
         val stream = MappingStream(mappings.value)
         val sourceMap = SourceMap { sourcePathToContent[it]?.let { StringReader(it) } }
         var currentGroup = SourceMapGroup().also { sourceMap.groups += it }
@@ -113,17 +125,20 @@ object SourceMapParser {
                 sourceIndex += stream.readInt() ?: return stream.createError("VLQ-encoded source index expected")
                 sourceLine += stream.readInt() ?: return stream.createError("VLQ-encoded source line expected")
                 sourceColumn += stream.readInt() ?: return stream.createError("VLQ-encoded source column expected")
-                if (stream.isEncodedInt) {
-                    stream.readInt() ?: return stream.createError("VLQ-encoded name index expected")
-                }
+                val name = if (stream.isEncodedInt) {
+                    nameIndex += stream.readInt() ?: return stream.createError("VLQ-encoded name index expected")
+                    if (nameIndex !in names.indices) {
+                        return stream.createError("Name index $nameIndex is out of bounds ${names.indices}")
+                    }
+                    names[nameIndex]
+                } else null
 
                 if (sourceIndex !in sources.indices) {
                     return stream.createError("Source index $sourceIndex is out of bounds ${sources.indices}")
                 }
-                currentGroup.segments += SourceMapSegment(jsColumn, sourceRoot + sources[sourceIndex], sourceLine, sourceColumn)
-            }
-            else {
-                currentGroup.segments += SourceMapSegment(jsColumn, null, -1, -1)
+                currentGroup.segments += SourceMapSegment(jsColumn, sourceRoot + sources[sourceIndex], sourceLine, sourceColumn, name)
+            } else {
+                currentGroup.segments += SourceMapSegment(jsColumn, null, -1, -1, null)
             }
 
             when {