pkg/sourcemap_testing/lib/src/stepping_helper.dart - sdk.git - Git at Google

 import 'dart:convert' show jsonDecode;
 import 'dart:io';

 import 'package:_fe_analyzer_shared/src/testing/annotated_code_helper.dart';
 import 'package:collection/collection.dart' show IterableNullableExtension;
 import 'package:dart2js_tools/src/util.dart';
 import 'package:expect/minitest.dart';
 import 'package:path/path.dart' as path;
 import 'package:source_maps/source_maps.dart';

 /// Runs D8 and steps as the AnnotatedCode dictates.
 ///
 /// Note that the compiled javascript is expected to be called "js.js" inside
 /// the outputPath directory. It is also expected that there is a "js.js.map"
 /// file. It is furthermore expected that the js has been compiled from a file
 /// in the same folder called test.dart.
 ProcessResult runD8AndStep(String outputPath, String testFileName,
     AnnotatedCode code, List<String> scriptD8Command) {
   var outputFile = path.join(outputPath, 'js.js');
   var sourcemapText = File('$outputFile.map').readAsStringSync();
   SingleMapping sourceMap = parseSingleMapping(jsonDecode(sourcemapText));

   Set<int?> mappedToLines = sourceMap.lines
       .map((entry) => entry.entries.map((entry) => entry.sourceLine).toSet())
       .fold(<int?>{}, (prev, e) => prev..addAll(e));

   for (Annotation annotation
       in code.annotations.where((a) => a.text.trim() == 'nm')) {
     if (mappedToLines.contains(annotation.lineNo - 1)) {
       fail('Was not allowed to have a mapping to line '
           '${annotation.lineNo}, but did.\n'
           'Sourcemap looks like this (note 0-indexed):\n'
           '${sourceMap.debugString}');
     }
   }

   List<String?> breakpoints = [];
   // Annotations are 1-based, js breakpoints are 0-based.
   for (Annotation breakAt
       in code.annotations.where((a) => a.text.trim() == 'bl')) {
     breakpoints
         .add(_getJsBreakpointLine(testFileName, sourceMap, breakAt.lineNo - 1));
   }
   for (Annotation breakAt
       in code.annotations.where((a) => a.text.trim().startsWith('bc:'))) {
     breakpoints.add(_getJsBreakpointLineAndColumn(
         testFileName, sourceMap, breakAt.lineNo - 1, breakAt.columnNo - 1));
   }

   File inspectorFile = File.fromUri(
       sdkRoot!.uri.resolve('pkg/sourcemap_testing/lib/src/js/inspector.js'));
   if (!inspectorFile.existsSync()) throw "Couldn't find 'inspector.js'";
   var outInspectorPath = path.join(outputPath, 'inspector.js');
   inspectorFile.copySync(outInspectorPath);
   String debugAction = 'Debugger.stepInto';
   if (code.annotations.any((a) => a.text.trim() == 'Debugger:stepOver')) {
     debugAction = 'Debugger.stepOver';
   }
   return _runD8(outInspectorPath, scriptD8Command, debugAction, breakpoints);
 }

 /// Translates the D8 js steps and checks against expectations.
 ///
 /// Note that the compiled javascript is expected to be called "js.js" inside
 /// the outputPath directory. It is also expected that there is a "js.js.map"
 /// file. It is furthermore expected that the js has been compiled from a file
 /// in the same folder called test.dart.
 void checkD8Steps(String outputPath, List<String> d8Output, AnnotatedCode code,
     {bool debug = false}) {
   var outputFilename = 'js.js';
   var outputFile = path.join(outputPath, outputFilename);
   var sourcemapText = File('$outputFile.map').readAsStringSync();
   SingleMapping sourceMap = parseSingleMapping(jsonDecode(sourcemapText));

   List<List<_DartStackTraceDataEntry>> result =
       _extractStackTraces(d8Output, sourceMap, outputFilename);

   List<_DartStackTraceDataEntry> trace =
       result.map((entry) => entry.first).toList();
   if (debug) _debugPrint(trace, outputPath);

   List<String> recordStops =
       trace.where((entry) => !entry.isError).map((entry) => '$entry').toList();

   Set<int> recordStopLines =
       trace.where((entry) => !entry.isError).map((entry) => entry.line).toSet();
   Set<String> recordStopLineColumns = trace
       .where((entry) => !entry.isError)
       .map((entry) => '${entry.line}:${entry.column}')
       .toSet();

   List<String?> expectedStops = [];
   for (Annotation annotation in code.annotations.where((annotation) =>
       annotation.text.trim().startsWith('s:') ||
       annotation.text.trim().startsWith('sl:') ||
       annotation.text.trim().startsWith('bc:'))) {
     String text = annotation.text.trim();
     int stopNum = int.parse(text.substring(text.indexOf(':') + 1));
     if (expectedStops.length < stopNum) expectedStops.length = stopNum;
     if (text.startsWith('sl:')) {
       expectedStops[stopNum - 1] = 'test.dart:${annotation.lineNo}:';
     } else {
       expectedStops[stopNum - 1] =
           'test.dart:${annotation.lineNo}:${annotation.columnNo}:';
     }
   }

   List<List<String>?> noBreaksStart = [];
   List<List<String>?> noBreaksEnd = [];
   for (Annotation annotation in code.annotations
       .where((annotation) => annotation.text.trim().startsWith('nbb:'))) {
     String text = annotation.text.trim();
     var split = text.split(':');
     int stopNum1 = int.parse(split[1]);
     int stopNum2 = int.parse(split[2]);
     if (noBreaksStart.length <= stopNum1) noBreaksStart.length = stopNum1 + 1;
     (noBreaksStart[stopNum1] ??= []).add('test.dart:${annotation.lineNo}:');
     if (noBreaksEnd.length <= stopNum2) noBreaksEnd.length = stopNum2 + 1;
     (noBreaksEnd[stopNum2] ??= []).add('test.dart:${annotation.lineNo}:');
   }

   _checkRecordedStops(
       recordStops, expectedStops, noBreaksStart, noBreaksEnd, debug);

   for (Annotation annotation in code.annotations
       .where((annotation) => annotation.text.trim() == 'nb')) {
     // Check that we didn't break where we're not allowed to.
     if (recordStopLines.contains(annotation.lineNo)) {
       fail('Was not allowed to stop on line ${annotation.lineNo}, but did!'
           '  Actual line stops: $recordStopLines${_debugHint(debug)}');
     }
   }
   for (Annotation annotation in code.annotations
       .where((annotation) => annotation.text.trim() == 'nbc')) {
     // Check that we didn't break where we're not allowed to.
     if (recordStopLineColumns
         .contains('${annotation.lineNo}:${annotation.columnNo}')) {
       fail('Was not allowed to stop on line ${annotation.lineNo} '
           'column ${annotation.columnNo}, but did!'
           '  Actual line stops: $recordStopLineColumns${_debugHint(debug)}');
     }
   }

   if (code.annotations.any((a) => a.text.trim() == 'fail')) {
     fail("Test contains 'fail' annotation.");
   }
 }

 void _checkRecordedStops(
     List<String> recordStops,
     List<String?> expectedStops,
     List<List<String>?> noBreaksStart,
     List<List<String>?> noBreaksEnd,
     bool debug) {
   // We want to find all expected lines in recorded lines in order, but allow
   // more in between in the recorded lines.
   // noBreaksStart and noBreaksStart gives instructions on what's *NOT* allowed
   // to be between those points though.

   int expectedIndex = 0;
   Set<String> aliveNoBreaks = {};
   if (noBreaksStart.isNotEmpty && noBreaksStart[0] != null) {
     aliveNoBreaks.addAll(noBreaksStart[0]!);
   }
   int stopNumber = 0;
   for (String recorded in recordStops) {
     stopNumber++;
     if (expectedIndex == expectedStops.length) break;
     var expectedStop = expectedStops[expectedIndex];
     if (expectedStop != null && '$recorded:'.contains(expectedStop)) {
       ++expectedIndex;
       if (noBreaksStart.length > expectedIndex &&
           noBreaksStart[expectedIndex] != null) {
         aliveNoBreaks.addAll(noBreaksStart[expectedIndex]!);
       }
       if (noBreaksEnd.length > expectedIndex &&
           noBreaksEnd[expectedIndex] != null) {
         aliveNoBreaks.removeAll(noBreaksEnd[expectedIndex]!);
       }
     } else {
       if (debug) {
         // One of the most helpful debugging tools is to see stops that weren't
         // matched. The most common failure is we didn't match one particular
         // stop location (e.g. because of the column). This gets reported
         // as an aliveNoBreaks failure (if the test is using no-breaks like
         // `nbb`) or it's reported as "stops don't match" message.
         //
         // Both failures are difficult to debug without seeing the stops that
         // didn't match. No breaks failures are misleading (the problem isn't
         // an incorrect break, but we missed a stop, so the aliveNoBreaks is
         // wrong), and the normal failure list dumps the entire stop list,
         // making it difficult to see where the mismatch was.
         //
         // Also we add 1 to expectedIndex, because the stop annotations are
         // 1-based in the source files (e.g. `/*s:1*/` is expectedIndex 0)
         print("Skipping stop `$recorded` that didn't match expected stop "
             '${expectedIndex + 1} `${expectedStops[expectedIndex]}`');
       }
       if (aliveNoBreaks
           .contains("${(recorded.split(":")..removeLast()).join(":")}:")) {
         fail("Break '$recorded' was found when it wasn't allowed "
             '(js step $stopNumber, after stop ${expectedIndex + 1}). '
             'This can happen when an expected stop was not matched'
             '${_debugHint(debug)}.');
       }
     }
   }
   if (expectedIndex != expectedStops.length) {
     // Didn't find everything.
     fail('Expected to find $expectedStops but found $recordStops'
         '${_debugHint(debug)}');
   }
 }

 /// If we're not in debug mode, this returns a message string with information
 /// about how to enable debug mode in the test runner.
 String _debugHint(bool debug) {
   if (debug) return ''; // already in debug mode
   return ' (pass -Ddebug=1 to the test runner to see debug information)';
 }

 void _debugPrint(List<_DartStackTraceDataEntry> trace, String outputPath) {
   StringBuffer sb = StringBuffer();
   var jsFile =
       File(path.join(outputPath, 'js.js')).readAsStringSync().split('\n');
   var dartFile =
       File(path.join(outputPath, 'test.dart')).readAsStringSync().split('\n');

   List<String> getSnippet(List<String> data, int line, int column) {
     List<String> result = List<String>.filled(5, '');
     if (line < 0 || column < 0) return result;

     for (int i = 0; i < 5; ++i) {
       int j = line - 2 + i;
       if (j < 0 || j >= data.length) continue;
       result[i] = data[j];
     }
     if (result[2].length >= column) {
       var before = result[2].substring(0, column);
       var after = result[2].substring(column);
       result[2] = '$before/*STOP*/$after';
     }
     return result;
   }

   List<String> sideBySide(List<String> a, List<String> b, int columns) {
     List<String> result = List<String>.filled(a.length, '');
     for (int i = 0; i < a.length; ++i) {
       String left = a[i].padRight(columns).substring(0, columns);
       String right = b[i].padRight(columns).substring(0, columns);
       result[i] = '$left  |  $right';
     }
     return result;
   }

   for (int i = 0; i < trace.length; ++i) {
     sb.write('\n\nStop #${i + 1}\n\n');
     if (trace[i].isError && trace[i].jsLine < 0) {
       sb.write('${trace[i].errorString}\n');
       continue;
     }
     var jsSnippet = getSnippet(jsFile, trace[i].jsLine, trace[i].jsColumn);
     var dartSnippet =
         getSnippet(dartFile, trace[i].line - 1, trace[i].column - 1);
     var view = sideBySide(jsSnippet, dartSnippet, 50);
     sb.writeAll(view, '\n');
   }

   print(sb.toString());
 }

 List<List<_DartStackTraceDataEntry>> _extractStackTraces(
     List<String> lines, SingleMapping sourceMap, String outputFilename) {
   List<List<_DartStackTraceDataEntry>> result = [];
   bool inStackTrace = false;
   List<String> currentStackTrace = <String>[];
   for (var line in lines) {
     if (line.trim() == '--- Debugger stacktrace start ---') {
       inStackTrace = true;
     } else if (line.trim() == '--- Debugger stacktrace end ---') {
       result.add(
           _extractStackTrace(currentStackTrace, sourceMap, outputFilename));
       currentStackTrace.clear();
       inStackTrace = false;
     } else if (inStackTrace) {
       currentStackTrace.add(line.trim());
     }
   }
   return result;
 }

 List<_DartStackTraceDataEntry> _extractStackTrace(
     List<String> js, SingleMapping sourceMap, String wantedFile) {
   List<_DartStackTraceDataEntry> result = [];
   for (String line in js) {
     if (!line.contains('$wantedFile:')) {
       result.add(_DartStackTraceDataEntry.error("Not correct file @ '$line'"));
       continue;
     }
     Iterable<Match> ms = RegExp(r'(\d+):(\d+)').allMatches(line);
     if (ms.isEmpty) {
       result.add(_DartStackTraceDataEntry.error(
           "Line and column not found for '$line'"));
       continue;
     }
     Match m = ms.first;
     int l = int.parse(m.group(1)!);
     int c = int.parse(m.group(2)!);
     SourceMapSpan? span = _getColumnOrPredecessor(sourceMap, l, c);
     if (span?.start == null) {
       result.add(_DartStackTraceDataEntry.errorWithJsPosition(
           "Source map not found for '$line'", l, c));
       continue;
     }
     var file = span!.sourceUrl?.pathSegments.last ?? '(unknown file)';
     result.add(_DartStackTraceDataEntry(
         file, span.start.line + 1, span.start.column + 1, l, c));
   }
   return result;
 }

 SourceMapSpan? _getColumnOrPredecessor(
     SingleMapping sourceMap, int line, int column) {
   SourceMapSpan? span = sourceMap.spanFor(line, column);
   if (span == null && line > 0) {
     span = sourceMap.spanFor(line - 1, 999999);
   }
   return span;
 }

 class _DartStackTraceDataEntry {
   final String? file;
   final int line;
   final int column;
   final String? errorString;
   final int jsLine;
   final int jsColumn;

   _DartStackTraceDataEntry(
       this.file, this.line, this.column, this.jsLine, this.jsColumn)
       : errorString = null;
   _DartStackTraceDataEntry.error(this.errorString)
       : file = null,
         line = -1,
         column = -1,
         jsLine = -1,
         jsColumn = -1;
   _DartStackTraceDataEntry.errorWithJsPosition(
       this.errorString, this.jsLine, this.jsColumn)
       : file = null,
         line = -1,
         column = -1;

   bool get isError => errorString != null;

   @override
   String toString() => isError ? errorString! : '$file:$line:$column';
 }

 class _PointMapping {
   final int fromLine;
   final int fromColumn;
   final int toLine;
   final int toColumn;

   _PointMapping(this.fromLine, this.fromColumn, this.toLine, this.toColumn);
 }

 /// Input and output is expected to be 0-based.
 ///
 /// The "magic 4" below is taken from
 /// https://github.com/ChromeDevTools/devtools-frontend/blob/fa18d70a995f06cb73365b2e5b8ae974cf60bd3a/front_end/sources/JavaScriptSourceFrame.js#L1520-L1523
 String? _getJsBreakpointLine(
     String testFileName, SingleMapping sourceMap, int breakOnLine) {
   List<_PointMapping> mappingsOnLines = [];
   for (var line in sourceMap.lines) {
     for (var entry in line.entries) {
       final sourceLine = entry.sourceLine;
       if (sourceLine == null) continue;
       final sourceColumn = entry.sourceColumn!;
       final sourceUrlId = entry.sourceUrlId;
       if (sourceLine >= breakOnLine &&
           sourceLine < breakOnLine + 4 &&
           sourceUrlId != null &&
           sourceMap.urls[sourceUrlId] == testFileName) {
         mappingsOnLines.add(
             _PointMapping(sourceLine, sourceColumn, line.line, entry.column));
       }
     }
   }

   if (mappingsOnLines.isEmpty) return null;

   mappingsOnLines.sort((a, b) {
     if (a.fromLine != b.fromLine) return a.fromLine - b.fromLine;
     if (a.fromColumn != b.fromColumn) return a.fromColumn - b.fromColumn;
     if (a.toLine != b.toLine) return a.toLine - b.toLine;
     return a.toColumn - b.toColumn;
   });
   _PointMapping first = mappingsOnLines.first;
   mappingsOnLines.retainWhere((p) => p.toLine >= first.toLine);

   _PointMapping last = mappingsOnLines.last;
   return '${first.toLine}:${first.toColumn}:${last.toLine}:${first.toColumn}';
 }

 /// Input and output is expected to be 0-based.
 String? _getJsBreakpointLineAndColumn(String testFileName,
     SingleMapping sourceMap, int breakOnLine, int breakOnColumn) {
   for (var line in sourceMap.lines) {
     for (var entry in line.entries) {
       if (entry.sourceLine == breakOnLine &&
           entry.sourceColumn == breakOnColumn &&
           entry.sourceUrlId != null &&
           sourceMap.urls[entry.sourceUrlId!] == testFileName) {
         return '${line.line}:${entry.column}';
       }
     }
   }
   return null;
 }

 ProcessResult _runD8(String outInspectorPath, List<String> scriptD8Command,
     String debugAction, List<String?> breakpoints) {
   var outInspectorPathRelative = path.relative(outInspectorPath);
   ProcessResult runResult = Process.runSync(d8Executable, [
     '--enable-inspector',
     outInspectorPathRelative,
     ...scriptD8Command,
     '--',
     debugAction,
     ...breakpoints.whereNotNull()
   ]);
   if (runResult.exitCode != 0) {
     print(runResult.stderr);
     print(runResult.stdout);
     throw 'Exit code: ${runResult.exitCode} from d8';
   }
   return runResult;
 }

 File? _cachedD8File;
 Directory? _cachedSdkRoot;
 File getD8File() {
   File attemptFileFromDir(Directory dir) {
     if (Platform.isWindows) {
       return File('${dir.path}${Platform.pathSeparator}d8/windows/d8.exe');
     } else if (Platform.isLinux) {
       return File('${dir.path}${Platform.pathSeparator}d8/linux/d8');
     } else if (Platform.isMacOS) {
       return File('${dir.path}${Platform.pathSeparator}d8/macos/d8');
     }
     throw UnsupportedError('Unsupported platform.');
   }

   File search() {
     Directory dir = File.fromUri(Platform.script).parent;
     while (dir.path.length > 1) {
       for (var entry in dir.listSync()) {
         if (entry is! Directory) continue;
         if (entry.path.endsWith('third_party')) {
           List<String> segments = entry.uri.pathSegments;
           if (segments[segments.length - 2] == 'third_party') {
             File possibleD8 = attemptFileFromDir(entry);
             if (possibleD8.existsSync()) {
               _cachedSdkRoot = dir;
               return possibleD8;
             }
           }
         }
       }
       dir = dir.parent;
     }

     throw 'Cannot find D8 directory.';
   }

   return _cachedD8File ??= search();
 }

 Directory? get sdkRoot {
   getD8File();
   return _cachedSdkRoot;
 }

 String get d8Executable {
   return getD8File().path;
 }
	import 'dart:convert' show jsonDecode;
	import 'dart:io';

	import 'package:_fe_analyzer_shared/src/testing/annotated_code_helper.dart';
	import 'package:collection/collection.dart' show IterableNullableExtension;
	import 'package:dart2js_tools/src/util.dart';
	import 'package:expect/minitest.dart';
	import 'package:path/path.dart' as path;
	import 'package:source_maps/source_maps.dart';

	/// Runs D8 and steps as the AnnotatedCode dictates.
	///
	/// Note that the compiled javascript is expected to be called "js.js" inside
	/// the outputPath directory. It is also expected that there is a "js.js.map"
	/// file. It is furthermore expected that the js has been compiled from a file
	/// in the same folder called test.dart.
	ProcessResult runD8AndStep(String outputPath, String testFileName,
	AnnotatedCode code, List<String> scriptD8Command) {
	var outputFile = path.join(outputPath, 'js.js');
	var sourcemapText = File('$outputFile.map').readAsStringSync();
	SingleMapping sourceMap = parseSingleMapping(jsonDecode(sourcemapText));

	Set<int?> mappedToLines = sourceMap.lines
	.map((entry) => entry.entries.map((entry) => entry.sourceLine).toSet())
	.fold(<int?>{}, (prev, e) => prev..addAll(e));

	for (Annotation annotation
	in code.annotations.where((a) => a.text.trim() == 'nm')) {
	if (mappedToLines.contains(annotation.lineNo - 1)) {
	fail('Was not allowed to have a mapping to line '
	'${annotation.lineNo}, but did.\n'
	'Sourcemap looks like this (note 0-indexed):\n'
	'${sourceMap.debugString}');
	}
	}

	List<String?> breakpoints = [];
	// Annotations are 1-based, js breakpoints are 0-based.
	for (Annotation breakAt
	in code.annotations.where((a) => a.text.trim() == 'bl')) {
	breakpoints
	.add(_getJsBreakpointLine(testFileName, sourceMap, breakAt.lineNo - 1));
	}
	for (Annotation breakAt
	in code.annotations.where((a) => a.text.trim().startsWith('bc:'))) {
	breakpoints.add(_getJsBreakpointLineAndColumn(
	testFileName, sourceMap, breakAt.lineNo - 1, breakAt.columnNo - 1));
	}

	File inspectorFile = File.fromUri(
	sdkRoot!.uri.resolve('pkg/sourcemap_testing/lib/src/js/inspector.js'));
	if (!inspectorFile.existsSync()) throw "Couldn't find 'inspector.js'";
	var outInspectorPath = path.join(outputPath, 'inspector.js');
	inspectorFile.copySync(outInspectorPath);
	String debugAction = 'Debugger.stepInto';
	if (code.annotations.any((a) => a.text.trim() == 'Debugger:stepOver')) {
	debugAction = 'Debugger.stepOver';
	}
	return _runD8(outInspectorPath, scriptD8Command, debugAction, breakpoints);
	}

	/// Translates the D8 js steps and checks against expectations.
	///
	/// Note that the compiled javascript is expected to be called "js.js" inside
	/// the outputPath directory. It is also expected that there is a "js.js.map"
	/// file. It is furthermore expected that the js has been compiled from a file
	/// in the same folder called test.dart.
	void checkD8Steps(String outputPath, List<String> d8Output, AnnotatedCode code,
	{bool debug = false}) {
	var outputFilename = 'js.js';
	var outputFile = path.join(outputPath, outputFilename);
	var sourcemapText = File('$outputFile.map').readAsStringSync();
	SingleMapping sourceMap = parseSingleMapping(jsonDecode(sourcemapText));

	List<List<_DartStackTraceDataEntry>> result =
	_extractStackTraces(d8Output, sourceMap, outputFilename);

	List<_DartStackTraceDataEntry> trace =
	result.map((entry) => entry.first).toList();
	if (debug) _debugPrint(trace, outputPath);

	List<String> recordStops =
	trace.where((entry) => !entry.isError).map((entry) => '$entry').toList();

	Set<int> recordStopLines =
	trace.where((entry) => !entry.isError).map((entry) => entry.line).toSet();
	Set<String> recordStopLineColumns = trace
	.where((entry) => !entry.isError)
	.map((entry) => '${entry.line}:${entry.column}')
	.toSet();

	List<String?> expectedStops = [];
	for (Annotation annotation in code.annotations.where((annotation) =>
	annotation.text.trim().startsWith('s:') \|\|
	annotation.text.trim().startsWith('sl:') \|\|
	annotation.text.trim().startsWith('bc:'))) {
	String text = annotation.text.trim();
	int stopNum = int.parse(text.substring(text.indexOf(':') + 1));
	if (expectedStops.length < stopNum) expectedStops.length = stopNum;
	if (text.startsWith('sl:')) {
	expectedStops[stopNum - 1] = 'test.dart:${annotation.lineNo}:';
	} else {
	expectedStops[stopNum - 1] =
	'test.dart:${annotation.lineNo}:${annotation.columnNo}:';
	}
	}

	List<List<String>?> noBreaksStart = [];
	List<List<String>?> noBreaksEnd = [];
	for (Annotation annotation in code.annotations
	.where((annotation) => annotation.text.trim().startsWith('nbb:'))) {
	String text = annotation.text.trim();
	var split = text.split(':');
	int stopNum1 = int.parse(split[1]);
	int stopNum2 = int.parse(split[2]);
	if (noBreaksStart.length <= stopNum1) noBreaksStart.length = stopNum1 + 1;
	(noBreaksStart[stopNum1] ??= []).add('test.dart:${annotation.lineNo}:');
	if (noBreaksEnd.length <= stopNum2) noBreaksEnd.length = stopNum2 + 1;
	(noBreaksEnd[stopNum2] ??= []).add('test.dart:${annotation.lineNo}:');
	}

	_checkRecordedStops(
	recordStops, expectedStops, noBreaksStart, noBreaksEnd, debug);

	for (Annotation annotation in code.annotations
	.where((annotation) => annotation.text.trim() == 'nb')) {
	// Check that we didn't break where we're not allowed to.
	if (recordStopLines.contains(annotation.lineNo)) {
	fail('Was not allowed to stop on line ${annotation.lineNo}, but did!'
	' Actual line stops: $recordStopLines${_debugHint(debug)}');
	}
	}
	for (Annotation annotation in code.annotations
	.where((annotation) => annotation.text.trim() == 'nbc')) {
	// Check that we didn't break where we're not allowed to.
	if (recordStopLineColumns
	.contains('${annotation.lineNo}:${annotation.columnNo}')) {
	fail('Was not allowed to stop on line ${annotation.lineNo} '
	'column ${annotation.columnNo}, but did!'
	' Actual line stops: $recordStopLineColumns${_debugHint(debug)}');
	}
	}

	if (code.annotations.any((a) => a.text.trim() == 'fail')) {
	fail("Test contains 'fail' annotation.");
	}
	}

	void _checkRecordedStops(
	List<String> recordStops,
	List<String?> expectedStops,
	List<List<String>?> noBreaksStart,
	List<List<String>?> noBreaksEnd,
	bool debug) {
	// We want to find all expected lines in recorded lines in order, but allow
	// more in between in the recorded lines.
	// noBreaksStart and noBreaksStart gives instructions on what's NOT allowed
	// to be between those points though.

	int expectedIndex = 0;
	Set<String> aliveNoBreaks = {};
	if (noBreaksStart.isNotEmpty && noBreaksStart[0] != null) {
	aliveNoBreaks.addAll(noBreaksStart[0]!);
	}
	int stopNumber = 0;
	for (String recorded in recordStops) {
	stopNumber++;
	if (expectedIndex == expectedStops.length) break;
	var expectedStop = expectedStops[expectedIndex];
	if (expectedStop != null && '$recorded:'.contains(expectedStop)) {
	++expectedIndex;
	if (noBreaksStart.length > expectedIndex &&
	noBreaksStart[expectedIndex] != null) {
	aliveNoBreaks.addAll(noBreaksStart[expectedIndex]!);
	}
	if (noBreaksEnd.length > expectedIndex &&
	noBreaksEnd[expectedIndex] != null) {
	aliveNoBreaks.removeAll(noBreaksEnd[expectedIndex]!);
	}
	} else {
	if (debug) {
	// One of the most helpful debugging tools is to see stops that weren't
	// matched. The most common failure is we didn't match one particular
	// stop location (e.g. because of the column). This gets reported
	// as an aliveNoBreaks failure (if the test is using no-breaks like
	// `nbb`) or it's reported as "stops don't match" message.
	//
	// Both failures are difficult to debug without seeing the stops that
	// didn't match. No breaks failures are misleading (the problem isn't
	// an incorrect break, but we missed a stop, so the aliveNoBreaks is
	// wrong), and the normal failure list dumps the entire stop list,
	// making it difficult to see where the mismatch was.
	//
	// Also we add 1 to expectedIndex, because the stop annotations are
	// 1-based in the source files (e.g. `/s:1/` is expectedIndex 0)
	print("Skipping stop `$recorded` that didn't match expected stop "
	'${expectedIndex + 1} `${expectedStops[expectedIndex]}`');
	}
	if (aliveNoBreaks
	.contains("${(recorded.split(":")..removeLast()).join(":")}:")) {
	fail("Break '$recorded' was found when it wasn't allowed "
	'(js step $stopNumber, after stop ${expectedIndex + 1}). '
	'This can happen when an expected stop was not matched'
	'${_debugHint(debug)}.');
	}
	}
	}
	if (expectedIndex != expectedStops.length) {
	// Didn't find everything.
	fail('Expected to find $expectedStops but found $recordStops'
	'${_debugHint(debug)}');
	}
	}

	/// If we're not in debug mode, this returns a message string with information
	/// about how to enable debug mode in the test runner.
	String _debugHint(bool debug) {
	if (debug) return ''; // already in debug mode
	return ' (pass -Ddebug=1 to the test runner to see debug information)';
	}

	void _debugPrint(List<_DartStackTraceDataEntry> trace, String outputPath) {
	StringBuffer sb = StringBuffer();
	var jsFile =
	File(path.join(outputPath, 'js.js')).readAsStringSync().split('\n');
	var dartFile =
	File(path.join(outputPath, 'test.dart')).readAsStringSync().split('\n');

	List<String> getSnippet(List<String> data, int line, int column) {
	List<String> result = List<String>.filled(5, '');
	if (line < 0 \|\| column < 0) return result;

	for (int i = 0; i < 5; ++i) {
	int j = line - 2 + i;
	if (j < 0 \|\| j >= data.length) continue;
	result[i] = data[j];
	}
	if (result[2].length >= column) {
	var before = result[2].substring(0, column);
	var after = result[2].substring(column);
	result[2] = '$before/STOP/$after';
	}
	return result;
	}

	List<String> sideBySide(List<String> a, List<String> b, int columns) {
	List<String> result = List<String>.filled(a.length, '');
	for (int i = 0; i < a.length; ++i) {
	String left = a[i].padRight(columns).substring(0, columns);
	String right = b[i].padRight(columns).substring(0, columns);
	result[i] = '$left \| $right';
	}
	return result;
	}

	for (int i = 0; i < trace.length; ++i) {
	sb.write('\n\nStop #${i + 1}\n\n');
	if (trace[i].isError && trace[i].jsLine < 0) {
	sb.write('${trace[i].errorString}\n');
	continue;
	}
	var jsSnippet = getSnippet(jsFile, trace[i].jsLine, trace[i].jsColumn);
	var dartSnippet =
	getSnippet(dartFile, trace[i].line - 1, trace[i].column - 1);
	var view = sideBySide(jsSnippet, dartSnippet, 50);
	sb.writeAll(view, '\n');
	}

	print(sb.toString());
	}

	List<List<_DartStackTraceDataEntry>> _extractStackTraces(
	List<String> lines, SingleMapping sourceMap, String outputFilename) {
	List<List<_DartStackTraceDataEntry>> result = [];
	bool inStackTrace = false;
	List<String> currentStackTrace = <String>[];
	for (var line in lines) {
	if (line.trim() == '--- Debugger stacktrace start ---') {
	inStackTrace = true;
	} else if (line.trim() == '--- Debugger stacktrace end ---') {
	result.add(
	_extractStackTrace(currentStackTrace, sourceMap, outputFilename));
	currentStackTrace.clear();
	inStackTrace = false;
	} else if (inStackTrace) {
	currentStackTrace.add(line.trim());
	}
	}
	return result;
	}

	List<_DartStackTraceDataEntry> _extractStackTrace(
	List<String> js, SingleMapping sourceMap, String wantedFile) {
	List<_DartStackTraceDataEntry> result = [];
	for (String line in js) {
	if (!line.contains('$wantedFile:')) {
	result.add(_DartStackTraceDataEntry.error("Not correct file @ '$line'"));
	continue;
	}
	Iterable<Match> ms = RegExp(r'(\d+):(\d+)').allMatches(line);
	if (ms.isEmpty) {
	result.add(_DartStackTraceDataEntry.error(
	"Line and column not found for '$line'"));
	continue;
	}
	Match m = ms.first;
	int l = int.parse(m.group(1)!);
	int c = int.parse(m.group(2)!);
	SourceMapSpan? span = _getColumnOrPredecessor(sourceMap, l, c);
	if (span?.start == null) {
	result.add(_DartStackTraceDataEntry.errorWithJsPosition(
	"Source map not found for '$line'", l, c));
	continue;
	}
	var file = span!.sourceUrl?.pathSegments.last ?? '(unknown file)';
	result.add(_DartStackTraceDataEntry(
	file, span.start.line + 1, span.start.column + 1, l, c));
	}
	return result;
	}

	SourceMapSpan? _getColumnOrPredecessor(
	SingleMapping sourceMap, int line, int column) {
	SourceMapSpan? span = sourceMap.spanFor(line, column);
	if (span == null && line > 0) {
	span = sourceMap.spanFor(line - 1, 999999);
	}
	return span;
	}

	class _DartStackTraceDataEntry {
	final String? file;
	final int line;
	final int column;
	final String? errorString;
	final int jsLine;
	final int jsColumn;

	_DartStackTraceDataEntry(
	this.file, this.line, this.column, this.jsLine, this.jsColumn)
	: errorString = null;
	_DartStackTraceDataEntry.error(this.errorString)
	: file = null,
	line = -1,
	column = -1,
	jsLine = -1,
	jsColumn = -1;
	_DartStackTraceDataEntry.errorWithJsPosition(
	this.errorString, this.jsLine, this.jsColumn)
	: file = null,
	line = -1,
	column = -1;

	bool get isError => errorString != null;

	@override
	String toString() => isError ? errorString! : '$file:$line:$column';
	}

	class _PointMapping {
	final int fromLine;
	final int fromColumn;
	final int toLine;
	final int toColumn;

	_PointMapping(this.fromLine, this.fromColumn, this.toLine, this.toColumn);
	}

	/// Input and output is expected to be 0-based.
	///
	/// The "magic 4" below is taken from
	/// https://github.com/ChromeDevTools/devtools-frontend/blob/fa18d70a995f06cb73365b2e5b8ae974cf60bd3a/front_end/sources/JavaScriptSourceFrame.js#L1520-L1523
	String? _getJsBreakpointLine(
	String testFileName, SingleMapping sourceMap, int breakOnLine) {
	List<_PointMapping> mappingsOnLines = [];
	for (var line in sourceMap.lines) {
	for (var entry in line.entries) {
	final sourceLine = entry.sourceLine;
	if (sourceLine == null) continue;
	final sourceColumn = entry.sourceColumn!;
	final sourceUrlId = entry.sourceUrlId;
	if (sourceLine >= breakOnLine &&
	sourceLine < breakOnLine + 4 &&
	sourceUrlId != null &&
	sourceMap.urls[sourceUrlId] == testFileName) {
	mappingsOnLines.add(
	_PointMapping(sourceLine, sourceColumn, line.line, entry.column));
	}
	}
	}

	if (mappingsOnLines.isEmpty) return null;

	mappingsOnLines.sort((a, b) {
	if (a.fromLine != b.fromLine) return a.fromLine - b.fromLine;
	if (a.fromColumn != b.fromColumn) return a.fromColumn - b.fromColumn;
	if (a.toLine != b.toLine) return a.toLine - b.toLine;
	return a.toColumn - b.toColumn;
	});
	_PointMapping first = mappingsOnLines.first;
	mappingsOnLines.retainWhere((p) => p.toLine >= first.toLine);

	_PointMapping last = mappingsOnLines.last;
	return '${first.toLine}:${first.toColumn}:${last.toLine}:${first.toColumn}';
	}

	/// Input and output is expected to be 0-based.
	String? _getJsBreakpointLineAndColumn(String testFileName,
	SingleMapping sourceMap, int breakOnLine, int breakOnColumn) {
	for (var line in sourceMap.lines) {
	for (var entry in line.entries) {
	if (entry.sourceLine == breakOnLine &&
	entry.sourceColumn == breakOnColumn &&
	entry.sourceUrlId != null &&
	sourceMap.urls[entry.sourceUrlId!] == testFileName) {
	return '${line.line}:${entry.column}';
	}
	}
	}
	return null;
	}

	ProcessResult _runD8(String outInspectorPath, List<String> scriptD8Command,
	String debugAction, List<String?> breakpoints) {
	var outInspectorPathRelative = path.relative(outInspectorPath);
	ProcessResult runResult = Process.runSync(d8Executable, [
	'--enable-inspector',
	outInspectorPathRelative,
	...scriptD8Command,
	'--',
	debugAction,
	...breakpoints.whereNotNull()
	]);
	if (runResult.exitCode != 0) {
	print(runResult.stderr);
	print(runResult.stdout);
	throw 'Exit code: ${runResult.exitCode} from d8';
	}
	return runResult;
	}

	File? _cachedD8File;
	Directory? _cachedSdkRoot;
	File getD8File() {
	File attemptFileFromDir(Directory dir) {
	if (Platform.isWindows) {
	return File('${dir.path}${Platform.pathSeparator}d8/windows/d8.exe');
	} else if (Platform.isLinux) {
	return File('${dir.path}${Platform.pathSeparator}d8/linux/d8');
	} else if (Platform.isMacOS) {
	return File('${dir.path}${Platform.pathSeparator}d8/macos/d8');
	}
	throw UnsupportedError('Unsupported platform.');
	}

	File search() {
	Directory dir = File.fromUri(Platform.script).parent;
	while (dir.path.length > 1) {
	for (var entry in dir.listSync()) {
	if (entry is! Directory) continue;
	if (entry.path.endsWith('third_party')) {
	List<String> segments = entry.uri.pathSegments;
	if (segments[segments.length - 2] == 'third_party') {
	File possibleD8 = attemptFileFromDir(entry);
	if (possibleD8.existsSync()) {
	_cachedSdkRoot = dir;
	return possibleD8;
	}
	}
	}
	}
	dir = dir.parent;
	}

	throw 'Cannot find D8 directory.';
	}

	return _cachedD8File ??= search();
	}

	Directory? get sdkRoot {
	getD8File();
	return _cachedSdkRoot;
	}

	String get d8Executable {
	return getD8File().path;
	}