Merge pull request microsoft#1535 from Microsoft/mergeMarkers1

Provide better error recovery when we encounter merge markers in the source.

Author: CyrusNajmabadi

src/compiler/core.ts

@@ -23,10 +23,10 @@ module ts {
 
  export interface StringSet extends Map<any> { }
 
- export function forEach<T, U>(array: T[], callback: (element: T) => U): U {
+ export function forEach<T, U>(array: T[], callback: (element: T, index: number) => U): U {
  if (array) {
  for (var i = 0, len = array.length; i < len; i++) {
- var result = callback(array[i]);
+ var result = callback(array[i], i);
  if (result) {
  return result;
  }

src/compiler/scanner.ts

@@ -7,10 +7,6 @@ module ts {
  (message: DiagnosticMessage, length: number): void;
  }
 
- export interface CommentCallback {
- (pos: number, end: number): void;
- }
-
  export interface Scanner {
  getStartPos(): number;
  getToken(): SyntaxKind;
@@ -396,8 +392,10 @@ module ts {
  var mergeConflictMarkerLength = "<<<<<<<".length;
 
  function isConflictMarkerTrivia(text: string, pos: number) {
+ Debug.assert(pos >= 0);
+
  // Conflict markers must be at the start of a line.
- if (pos > 0 && isLineBreak(text.charCodeAt(pos - 1))) {
+ if (pos === 0 || isLineBreak(text.charCodeAt(pos - 1))) {
  var ch = text.charCodeAt(pos);
 
  if ((pos + mergeConflictMarkerLength) < text.length) {
@@ -415,10 +413,31 @@ module ts {
  return false;
  }
 
- function scanConflictMarkerTrivia(text: string, pos: number) {
+ function scanConflictMarkerTrivia(text: string, pos: number, error?: ErrorCallback) {
+ if (error) {
+ error(Diagnostics.Merge_conflict_marker_encountered, mergeConflictMarkerLength);
+ }
+
+ var ch = text.charCodeAt(pos);
  var len = text.length;
- while (pos < len && !isLineBreak(text.charCodeAt(pos))) {
- pos++;
+
+ if (ch === CharacterCodes.lessThan || ch === CharacterCodes.greaterThan) {
+ while (pos < len && !isLineBreak(text.charCodeAt(pos))) {
+ pos++;
+ }
+ }
+ else {
+ Debug.assert(ch === CharacterCodes.equals);
+ // Consume everything from the start of the mid-conlict marker to the start of the next
+ // end-conflict marker.
+ while (pos < len) {
+ var ch = text.charCodeAt(pos);
+ if (ch === CharacterCodes.greaterThan && isConflictMarkerTrivia(text, pos)) {
+ break;
+ }
+
+ pos++;
+ }
  }
 
  return pos;
@@ -1057,8 +1076,7 @@ module ts {
  return pos++, token = SyntaxKind.SemicolonToken;
  case CharacterCodes.lessThan:
  if (isConflictMarkerTrivia(text, pos)) {
- mergeConflictError();
- pos = scanConflictMarkerTrivia(text, pos);
+ pos = scanConflictMarkerTrivia(text, pos, error);
  if (skipTrivia) {
  continue;
  }
@@ -1079,8 +1097,7 @@ module ts {
  return pos++, token = SyntaxKind.LessThanToken;
  case CharacterCodes.equals:
  if (isConflictMarkerTrivia(text, pos)) {
- mergeConflictError();
- pos = scanConflictMarkerTrivia(text, pos);
+ pos = scanConflictMarkerTrivia(text, pos, error);
  if (skipTrivia) {
  continue;
  }
@@ -1101,8 +1118,7 @@ module ts {
  return pos++, token = SyntaxKind.EqualsToken;
  case CharacterCodes.greaterThan:
  if (isConflictMarkerTrivia(text, pos)) {
- mergeConflictError();
- pos = scanConflictMarkerTrivia(text, pos);
+ pos = scanConflictMarkerTrivia(text, pos, error);
  if (skipTrivia) {
  continue;
  }
@@ -1171,10 +1187,6 @@ module ts {
  }
  }
 
- function mergeConflictError() {
- error(Diagnostics.Merge_conflict_marker_encountered, mergeConflictMarkerLength);
- }
-
  function reScanGreaterToken(): SyntaxKind {
  if (token === SyntaxKind.GreaterThanToken) {
  if (text.charCodeAt(pos) === CharacterCodes.greaterThan) {

src/compiler/types.ts

@@ -16,6 +16,8 @@ module ts {
  MultiLineCommentTrivia,
  NewLineTrivia,
  WhitespaceTrivia,
+ // We detect and provide better error recovery when we encounter a git merge marker. This
+ // allows us to edit files with git-conflict markers in them in a much more pleasant manner.
  ConflictMarkerTrivia,
  // Literals
  NumericLiteral,
@@ -272,8 +274,6 @@ module ts {
  LastLiteralToken = NoSubstitutionTemplateLiteral,
  FirstTemplateToken = NoSubstitutionTemplateLiteral,
  LastTemplateToken = TemplateTail,
- FirstOperator = SemicolonToken,
- LastOperator = CaretEqualsToken,
  FirstBinaryOperator = LessThanToken,
  LastBinaryOperator = CaretEqualsToken,
  FirstNode = QualifiedName,

src/services/formatting/tokenRange.ts

@@ -125,10 +125,8 @@ module ts.formatting {
  static Any: TokenRange = TokenRange.AllTokens();
  static AnyIncludingMultilineComments = TokenRange.FromTokens(TokenRange.Any.GetTokens().concat([SyntaxKind.MultiLineCommentTrivia]));
  static Keywords = TokenRange.FromRange(SyntaxKind.FirstKeyword, SyntaxKind.LastKeyword);
- static Operators = TokenRange.FromRange(SyntaxKind.FirstOperator, SyntaxKind.LastOperator);
  static BinaryOperators = TokenRange.FromRange(SyntaxKind.FirstBinaryOperator, SyntaxKind.LastBinaryOperator);
  static BinaryKeywordOperators = TokenRange.FromTokens([SyntaxKind.InKeyword, SyntaxKind.InstanceOfKeyword]);
- static ReservedKeywords = TokenRange.FromRange(SyntaxKind.FirstFutureReservedWord, SyntaxKind.LastFutureReservedWord);
  static UnaryPrefixOperators = TokenRange.FromTokens([SyntaxKind.PlusPlusToken, SyntaxKind.MinusMinusToken, SyntaxKind.TildeToken, SyntaxKind.ExclamationToken]);
  static UnaryPrefixExpressions = TokenRange.FromTokens([SyntaxKind.NumericLiteral, SyntaxKind.Identifier, SyntaxKind.OpenParenToken, SyntaxKind.OpenBracketToken, SyntaxKind.OpenBraceToken, SyntaxKind.ThisKeyword, SyntaxKind.NewKeyword]);
  static UnaryPreincrementExpressions = TokenRange.FromTokens([SyntaxKind.Identifier, SyntaxKind.OpenParenToken, SyntaxKind.ThisKeyword, SyntaxKind.NewKeyword]);