[JS IR] Improve stepping test executor

Don't search for box function in the generated code;
instead, stop the execution right before calling it.

This makes stepping tests more accurate.

compiler/testData/debug/stepping/conjunction.kt

@@ -34,4 +34,11 @@ fun getD() = true
 
 // EXPECTATIONS JS_IR
 // test.kt:3 box
-// test.kt:11 box
+// test.kt:13 getA
+// test.kt:4 box
+// test.kt:15 getB
+// test.kt:5 box
+// test.kt:17 getC
+// test.kt:9 box
+// test.kt:3 box
+// test.kt:11 box

compiler/testData/debug/stepping/for.kt

@@ -31,4 +31,5 @@ inline fun foo(n: Int) {}
 // test.kt:3 box
 // test.kt:3 box
 // test.kt:3 box
-// test.kt:6 box
+// test.kt:3 box
+// test.kt:6 box

compiler/testData/debug/stepping/ifWithInlineInCondition.kt

@@ -56,6 +56,7 @@ fun nop() {}
 // test.kt:21 box
 
 // EXPECTATIONS JS_IR
+// test.kt:24 box
 // test.kt:3 box
 // test.kt:4 box
 // test.kt:30 nop
@@ -74,4 +75,4 @@ fun nop() {}
 // test.kt:15 box
 // test.kt:19 box
 // test.kt:30 nop
-// test.kt:21 box
+// test.kt:21 box

compiler/testData/debug/stepping/jsCode.kt

@@ -33,10 +33,10 @@ val jesse1VarDecl = "var jesse1 = _.exclamate(jesse);"
 
 // FILE: test.kt
 
-fun noop() {}
+
 
 fun box() {
-    noop()
+
     exclamateAndConcat(
         "hello",
         "world")
@@ -56,8 +56,6 @@ fun box() {
 }
 
 // EXPECTATIONS
-// test.kt:39 box
-// test.kt:36 noop
 // test.kt:41 box
 // test.kt:42 box
 // a.kt:11 box
@@ -79,4 +77,4 @@ fun box() {
 // a.kt:6 exclamate
 // a.kt:29 box
 // a.kt:22 value
-// test.kt:56 box
+// test.kt:56 box

compiler/testData/debug/stepping/kt42208.kt

@@ -19,6 +19,7 @@ inline fun foo() = {
 // test.kt:5 box
 
 // EXPECTATIONS JS_IR
+// test1.kt:9 box
 // test.kt:4 box
 // test1.kt:6 box$lambda
-// test.kt:5 box
+// test.kt:5 box

compiler/testData/debug/stepping/kt42208b.kt

@@ -25,7 +25,8 @@ inline fun foo() = {
 // test.kt:6 box
 
 // EXPECTATIONS JS_IR
+// test1.kt:10 box
 // test.kt:4 box
 // test.kt:5 box
 // test1.kt:7 box$lambda
-// test.kt:6 box
+// test.kt:6 box

compiler/testData/debug/stepping/kt42208c.kt

@@ -38,6 +38,7 @@ fun baz(v:(() -> Unit)) {
 // test.kt:7 box
 
 // EXPECTATIONS JS_IR
+// test1.kt:11 box
 // test.kt:4 box
 // test3.kt:14 baz
 // test1.kt:8 box$lambda
@@ -48,4 +49,4 @@ fun baz(v:(() -> Unit)) {
 // test3.kt:14 baz
 // test1.kt:8 box$lambda
 // test3.kt:15 baz
-// test.kt:7 box
+// test.kt:7 box

compiler/testData/debug/stepping/nestedInline.kt

@@ -65,5 +65,12 @@ inline fun html(init: () -> Unit) {
 // test.kt:21 box
 
 // EXPECTATIONS JS_IR
+// test.kt:7 box
+// 1.kt:33 box
+// 1.kt:36 box
+// 1.kt:37 box
+// 1.kt:37 box
+// 1.kt:41 box
+// test.kt:15 box
 // test.kt:19 box
 // test.kt:21 box

compiler/testData/debug/stepping/simpleInlineDefaultArg.kt

@@ -38,3 +38,6 @@ fun box(): String {
 // test.kt:10 box
 
 // EXPECTATIONS JS_IR
+// test.kt:3 box
+// test.kt:5 box
+// test.kt:6 box

compiler/testData/debug/stepping/smapInlineAsArgument.kt

@@ -38,6 +38,7 @@ fun fail() : String {
 // test.kt:9 box
 
 // EXPECTATIONS JS_IR
+// test.kt:16 box
 // test.kt:4 box
 // test.kt:20 fail
 // test.kt:4 box
@@ -47,4 +48,4 @@ fun fail() : String {
 // test.kt:16 box
 // test.kt:7 box
 // test.kt:13 checkEquals
-// test.kt:9 box
+// test.kt:9 box

compiler/testData/debug/stepping/smapInlineAsInfixArgument.kt

@@ -36,6 +36,7 @@ fun fail() : String {
 // test.kt:11 box
 
 // EXPECTATIONS JS_IR
+// test.kt:14 box
 // test.kt:6 box
 // test.kt:18 fail
 // test.kt:6 box
@@ -45,4 +46,4 @@ fun fail() : String {
 // test.kt:14 box
 // test.kt:9 box
 // test.kt:3 execute
-// test.kt:11 box
+// test.kt:11 box

compiler/testData/debug/stepping/smapInlineAsInlineArgument.kt

@@ -38,6 +38,7 @@ fun fail() : String {
 // test.kt:9 box
 
 // EXPECTATIONS JS_IR
+// test.kt:16 box
 // test.kt:4 box
 // test.kt:5 box
 // test.kt:20 fail
@@ -47,4 +48,4 @@ fun fail() : String {
 // test.kt:16 box
 // test.kt:8 box
 // test.kt:16 box
-// test.kt:9 box
+// test.kt:9 box

compiler/testData/debug/stepping/smapInlineInIntrinsicArgument.kt

@@ -37,10 +37,11 @@ fun fail() : String {
 // test.kt:9 box
 
 // EXPECTATIONS JS_IR
+// test.kt:12 box
 // test.kt:4 box
 // test.kt:16 fail
 // test.kt:7 box
 // test.kt:16 fail
 // test.kt:12 box
 // test.kt:7 box
-// test.kt:9 box
+// test.kt:9 box

compiler/testData/debug/stepping/suspendFunWithLambdaParameter.kt

@@ -19,7 +19,13 @@ suspend fun box() {
 // test.kt:11 box
 
 // EXPECTATIONS JS_IR
+// test.kt:7 box
+// test.kt:7 <init>
+// test.kt:7 <init>
+// test.kt:7 box
+// test.kt:7 box
+// test.kt:7 box
 // test.kt:8 doResume
 // test.kt:4 foo
 // test.kt:4 foo
-// test.kt:9 box$lambda
+// test.kt:9 box$lambda

js/js.tests/test/org/jetbrains/kotlin/js/test/debugger/stepping_test_executor.js

@@ -14,7 +14,13 @@ const code = fs.readFileSync(testFilePath, 'utf-8');
 
 try {
     vm.runInContext(code, sandbox, testFilePath);
-    vm.runInContext('main.box()', sandbox);
+    // language=JavaScript
+    vm.runInContext(`
+            debugger;
+            main.box();
+        `,
+        sandbox
+    );
 } catch (e) {
     // Ignore any exceptions
 }

js/js.tests/test/org/jetbrains/kotlin/js/test/handlers/JsDebugRunner.kt

@@ -5,16 +5,12 @@
 package org.jetbrains.kotlin.js.test.handlers
 
 import kotlinx.coroutines.withTimeout
-import org.jetbrains.kotlin.KtPsiSourceFileLinesMapping
 import org.jetbrains.kotlin.ir.backend.js.transformers.irToJs.TranslationMode
 import org.jetbrains.kotlin.js.parser.sourcemaps.*
 import org.jetbrains.kotlin.js.test.debugger.*
 import org.jetbrains.kotlin.js.test.utils.getAllFilesForRunner
-import org.jetbrains.kotlin.js.test.utils.getBoxFunction
-import org.jetbrains.kotlin.psi.psiUtil.startOffset
 import org.jetbrains.kotlin.test.TargetBackend
 import org.jetbrains.kotlin.test.directives.JsEnvironmentConfigurationDirectives
-import org.jetbrains.kotlin.test.model.TestFile
 import org.jetbrains.kotlin.test.model.TestModule
 import org.jetbrains.kotlin.test.services.TestServices
 import org.jetbrains.kotlin.test.services.configuration.JsEnvironmentConfigurator
@@ -29,7 +25,7 @@ import java.net.URISyntaxException
 /**
  * This class is an analogue of the [DebugRunner][org.jetbrains.kotlin.test.backend.handlers.DebugRunner] from JVM stepping tests.
  *
- * It runs a generated JavaScript file under a debugger, sets a breakpoint in the beginning of the `box` function
+ * It runs a generated JavaScript file under a debugger, stops right before entering the `box` function,
  * and performs the "step into" action until there is nothing more to step into. On each pause it records the source file name,
  * the source line and the function name of the current call frame, and compares this data with the expectations written in the test file.
  *
@@ -72,47 +68,54 @@ class JsDebugRunner(testServices: TestServices) : AbstractJsArtifactsCollector(t
         sourceMap: SourceMap,
         mainModule: TestModule,
     ) {
-        val (testFileWithBoxFunction, boxFunctionStartLine) = getBoxFunctionStartLocation(mainModule)
+        val originalFile = mainModule.files.first { !it.isAdditional }.originalFile
-        val originalFileWithBoxFunction = testFileWithBoxFunction.originalFile
-
-        val boxFunctionLineInGeneratedFile =
-            sourceMap.breakpointLineInGeneratedFile(originalFileWithBoxFunction, boxFunctionStartLine)
-
-        if (boxFunctionLineInGeneratedFile < 0)
-            error("Could not find the location of the 'box' function in the generated file")
-
         val debuggerFacade = NodeJsDebuggerFacade(jsFilePath)
 
-        val jsFileURI = File(jsFilePath).absoluteFile.toURI().withAuthority("")
+        val jsFile = File(jsFilePath)
+
+        val jsFileURI = jsFile.makeURI()
 
         val loggedItems = mutableListOf<SteppingTestLoggedData>()
+
         debuggerFacade.run {
-            with(debuggerFacade) {
+            debugger.resume()
-                val boxFunctionBreakpoint = debugger.setBreakpointByUrl(boxFunctionLineInGeneratedFile, jsFileURI.toString())
+            waitForResumeEvent()
-                debugger.resume()
+            waitForPauseEvent {
-                waitForResumeEvent()
+                it.reason == Debugger.PauseReason.OTHER // hit the 'debugger' statement
-                waitForPauseEvent {
+            }
-                    it.reason == Debugger.PauseReason.OTHER && it.hitBreakpoints.contains(boxFunctionBreakpoint.breakpointId)
+
-                }
+            suspend fun repeatedlyStepInto(action: suspend (Debugger.CallFrame) -> Boolean) {
                 while (true) {
                     val topMostCallFrame = waitForPauseEvent().callFrames[0]
-                    try {
+                    if (!action(topMostCallFrame)) break
-                        if (URI(scriptUrlByScriptId(topMostCallFrame.location.scriptId)) != jsFileURI) break
-                    } catch (_: URISyntaxException) {
-                        // Probably something like 'evalmachine.<anonymous>' brought us here. Ignore.
-                    }
-                    addCallFrameInfoToLoggedItems(sourceMap, topMostCallFrame, loggedItems)
                     debugger.stepInto()
                     waitForResumeEvent()
                 }
-                debugger.resume()
-                waitForResumeEvent()
             }
+
+            fun Debugger.CallFrame.isInFileUnderTest() = try {
+                URI(scriptUrlByScriptId(location.scriptId)) == jsFileURI
+            } catch (_: URISyntaxException) {
+                false
+            }
+
+            repeatedlyStepInto {
+                !it.isInFileUnderTest()
+            }
+            repeatedlyStepInto { callFrame ->
+                callFrame.isInFileUnderTest().also {
+                    if (it)
+                        addCallFrameInfoToLoggedItems(sourceMap, callFrame, loggedItems)
+                }
+            }
+
+            debugger.resume()
+            waitForResumeEvent()
         }
         checkSteppingTestResult(
             mainModule.frontendKind,
             mainModule.targetBackend ?: TargetBackend.JS_IR,
-            originalFileWithBoxFunction,
+            originalFile,
             loggedItems
         )
     }
@@ -123,82 +126,24 @@ class JsDebugRunner(testServices: TestServices) : AbstractJsArtifactsCollector(t
         loggedItems: MutableList<SteppingTestLoggedData>
     ) {
         val originalFunctionName = topMostCallFrame.functionLocation?.let {
-            sourceMap.getSourceLineForGeneratedLocation(it)?.name
+            sourceMap.segmentForGeneratedLocation(it.lineNumber, it.columnNumber)?.name
         }
-        sourceMap.getSourceLineForGeneratedLocation(topMostCallFrame.location)?.let { (_, sourceFile, sourceLine, _, _) ->
+        sourceMap.segmentForGeneratedLocation(
+            topMostCallFrame.location.lineNumber,
+            topMostCallFrame.location.columnNumber
+        )?.let { (_, sourceFile, sourceLine, _, _) ->
             if (sourceFile == null || sourceLine < 0) return@let
             val testFileName = testFileNameFromMappedLocation(sourceFile, sourceLine) ?: return
-            val expectation =
+            val expectation = formatAsSteppingTestExpectation(
-                formatAsSteppingTestExpectation(testFileName, sourceLine + 1, originalFunctionName ?: topMostCallFrame.functionName, false)
+                testFileName,
+                sourceLine + 1,
+                originalFunctionName ?: topMostCallFrame.functionName,
+                false,
+            )
             loggedItems.add(SteppingTestLoggedData(sourceLine + 1, false, expectation))
         }
     }
 
-    /**
-     * Returns the test file and the line number in that file where the body of the `box` function begins.
-     */
-    private fun getBoxFunctionStartLocation(mainModule: TestModule): Pair<TestFile, Int> {
-        val boxFunction = getBoxFunction(testServices) ?: error("Missing 'box' function")
-        val file = boxFunction.containingKtFile
-        val mapping = KtPsiSourceFileLinesMapping(file)
-        val firstStatementOffset = boxFunction.bodyBlockExpression?.firstStatement?.startOffset
-            ?: boxFunction.bodyExpression?.startOffset
-            ?: boxFunction.startOffset
-        return mainModule.files.single { it.name == file.name } to mapping.getLineByOffset(firstStatementOffset)
-    }
-
-    /**
-     * Maps the location in the source file to the location in the generated file.
-     *
-     * The Node.js debugger is not sourcemap-aware, so we need to set a breakpoint in the `box` function in the generated JS file.
-     *
-     * We don't know where the generated `box` function is located, so we use the source map to figure it out.
-     *
-     * This is basically what Intellij IDEA's built-in JavaScript debugger does when you set a breakpoint in a source file: it tries
-     * to map the location of the breakpoint in the source file to a location in the generated file. Here we use a simplified
-     * algorithm for that.
-     */
-    private fun SourceMap.breakpointLineInGeneratedFile(sourceFile: File, sourceLine: Int): Int {
-        val sourceFileAbsolutePath = sourceFile.absoluteFile.normalize()
-        var candidateSegment: Pair<Int, SourceMapSegment>? = null
-        for ((generatedLineNumber, group) in groups.withIndex()) {
-            for (segment in group.segments) {
-                if (segment.sourceFileName?.let { File(it).absoluteFile.normalize() } != sourceFileAbsolutePath ||
-                    segment.sourceLineNumber != sourceLine)
-                    continue
-                if (candidateSegment == null)
-                    candidateSegment = generatedLineNumber to segment
-                // Find the segment that points to the earliest column in the source file
-                if (segment.sourceColumnNumber < candidateSegment.second.sourceColumnNumber)
-                    candidateSegment = generatedLineNumber to segment
-            }
-        }
-        return candidateSegment?.first ?: -1
-    }
-
-    /**
-     * Maps [location] in the generated JavaScript file to the corresponding location in a source file.
-     * @return The source file path (as specified in the source map) and the line number in that source file.
-     */
-    private fun SourceMap.getSourceLineForGeneratedLocation(location: Debugger.Location): SourceMapSegment? {
-
-        val group = groups.getOrNull(location.lineNumber)?.takeIf { it.segments.isNotEmpty() } ?: return null
-        val columnNumber = location.columnNumber ?: return group.segments[0]
-        return if (columnNumber <= group.segments[0].generatedColumnNumber) {
-            group.segments[0]
-        } else {
-            val candidateIndex = group.segments.indexOfFirst {
-                columnNumber <= it.generatedColumnNumber
-            }
-            if (candidateIndex < 0)
-                null
-            else if (candidateIndex == 0 || group.segments[candidateIndex].generatedColumnNumber == columnNumber)
-                group.segments[candidateIndex]
-            else
-                group.segments[candidateIndex - 1]
-        }
-    }
-
     /**
      * An original test file may represent multiple source files (by using the `// FILE: myFile.kt` comments).
      * Sourcemaps contain paths to original test files. However, in test expectations we write names as in the `// FILE:` comments.
@@ -206,9 +151,10 @@ class JsDebugRunner(testServices: TestServices) : AbstractJsArtifactsCollector(t
      */
     private fun testFileNameFromMappedLocation(originalFilePath: String, originalFileLineNumber: Int): String? {
         val originalFile = File(originalFilePath)
-        return testServices.moduleStructure.modules.flatMap { it.files }.findLast {
+        return testServices.moduleStructure.modules.asSequence().flatMap { module -> module.files.asSequence().filter { !it.isAdditional } }
-            it.originalFile.absolutePath == originalFile.absolutePath && it.startLineNumberInOriginalFile <= originalFileLineNumber
+            .findLast {
-        }?.name
+                it.originalFile.absolutePath == originalFile.absolutePath && it.startLineNumberInOriginalFile <= originalFileLineNumber
+            }?.name
     }
 }
 
@@ -250,26 +196,52 @@ private class NodeJsDebuggerFacade(jsFilePath: String) {
     /**
      * By the time [body] is called, the execution is paused, no code is executed yet.
      */
-    fun <T> run(body: suspend NodeJsInspectorClientContext.() -> T) = inspector.run {
+    fun <T> run(body: suspend Context.() -> T) = inspector.run {
         debugger.enable()
         debugger.setSkipAllPauses(false)
         runtime.runIfWaitingForDebugger()
-        waitForPauseEvent { it.reason == Debugger.PauseReason.BREAK_ON_START }
 
-        withTimeout(30000) {
+        with(Context(this)) {
-            body()
+            waitForPauseEvent { it.reason == Debugger.PauseReason.BREAK_ON_START }
+
+            withTimeout(30000) {
+                body()
+            }
         }
     }
 
-    fun scriptUrlByScriptId(scriptId: Runtime.ScriptId) = scriptUrls[scriptId] ?: error("unknown scriptId")
+    inner class Context(private val underlying: NodeJsInspectorClientContext) : NodeJsInspectorClientContext by underlying {
 
-    suspend fun NodeJsInspectorClientContext.waitForPauseEvent(suchThat: (Debugger.Event.Paused) -> Boolean = { true }) =
+        fun scriptUrlByScriptId(scriptId: Runtime.ScriptId) = scriptUrls[scriptId] ?: error("unknown scriptId $scriptId")
-        waitForValueToBecomeNonNull {
-            pausedEvent?.takeIf(suchThat)
-        }
 
-    suspend fun NodeJsInspectorClientContext.waitForResumeEvent() = waitForConditionToBecomeTrue { pausedEvent == null }
+        suspend fun waitForPauseEvent(suchThat: (Debugger.Event.Paused) -> Boolean = { true }) =
+            waitForValueToBecomeNonNull {
+                pausedEvent?.takeIf(suchThat)
+            }
+
+        suspend fun waitForResumeEvent() = waitForConditionToBecomeTrue { pausedEvent == null }
+    }
 }
 
+private fun File.makeURI(): URI = absoluteFile.toURI().withAuthority("")
+
 private fun URI.withAuthority(newAuthority: String?) =
     URI(scheme, newAuthority, path, query, fragment)
+
+private fun SourceMap.segmentForGeneratedLocation(lineNumber: Int, columnNumber: Int?): SourceMapSegment? {
+
+    val group = groups.getOrNull(lineNumber)?.takeIf { it.segments.isNotEmpty() } ?: return null
+    return if (columnNumber == null || columnNumber <= group.segments[0].generatedColumnNumber) {
+        group.segments[0]
+    } else {
+        val candidateIndex = group.segments.indexOfFirst {
+            columnNumber <= it.generatedColumnNumber
+        }
+        if (candidateIndex < 0)
+            null
+        else if (candidateIndex == 0 || group.segments[candidateIndex].generatedColumnNumber == columnNumber)
+            group.segments[candidateIndex]
+        else
+            group.segments[candidateIndex - 1]
+    }
+}