Compare JS source maps in readable way in IC tests

build-common/test/org/jetbrains/kotlin/incremental/testingUtils/classFilesComparison.kt

@@ -17,7 +17,11 @@
 package org.jetbrains.kotlin.incremental.testingUtils
 
 import com.intellij.openapi.util.io.FileUtil
+import com.sun.xml.internal.messaging.saaj.util.ByteOutputStream
 import org.jetbrains.kotlin.incremental.LocalFileKotlinClass
+import org.jetbrains.kotlin.js.parser.sourcemaps.SourceMapError
+import org.jetbrains.kotlin.js.parser.sourcemaps.SourceMapParser
+import org.jetbrains.kotlin.js.parser.sourcemaps.SourceMapSuccess
 import org.jetbrains.kotlin.load.kotlin.header.KotlinClassHeader
 import org.jetbrains.kotlin.metadata.DebugProtoBuf
 import org.jetbrains.kotlin.metadata.js.DebugJsProtoBuf
@@ -32,10 +36,7 @@ import org.jetbrains.org.objectweb.asm.ClassReader
 import org.jetbrains.org.objectweb.asm.util.TraceClassVisitor
 import org.junit.Assert
 import org.junit.Assert.assertNotNull
-import java.io.ByteArrayInputStream
-import java.io.File
-import java.io.PrintWriter
-import java.io.StringWriter
+import java.io.*
 import java.util.*
 import java.util.zip.CRC32
 import java.util.zip.GZIPInputStream
@@ -186,6 +187,22 @@ private fun metaJsToString(metaJsFile: File): String {
     return out.toString()
 }
 
+private fun sourceMapFileToString(sourceMapFile: File, generatedJsFile: File): String {
+    val sourceMapParseResult = SourceMapParser.parse(StringReader(sourceMapFile.readText()))
+    return when (sourceMapParseResult) {
+        is SourceMapSuccess -> {
+            val bytesOut = ByteArrayOutputStream()
+            PrintStream(bytesOut).use { printStream ->
+                sourceMapParseResult.value.debugVerbose(printStream, generatedJsFile)
+            }
+            bytesOut.toString()
+        }
+        is SourceMapError -> {
+            sourceMapParseResult.message
+        }
+    }
+}
+
 private fun getExtensionRegistry(): ExtensionRegistry {
     val registry = ExtensionRegistry.newInstance()!!
     DebugJvmProtoBuf.registerAllExtensions(registry)
@@ -200,6 +217,10 @@ private fun fileToStringRepresentation(file: File): String {
         file.name.endsWith(KotlinJavascriptMetadataUtils.META_JS_SUFFIX) -> {
             metaJsToString(file)
         }
+        file.name.endsWith(".js.map") -> {
+            val generatedJsPath = file.canonicalPath.removeSuffix(".map")
+            sourceMapFileToString(file, File(generatedJsPath))
+        }
         else -> {
             file.readText()
         }