Change to dart command line analyzer- Remove the rich toString in AnalyzerError to prevent .content…

pkg/analyzer/lib/src/error.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 library error;
 
 import 'dart:collection';
 import 'dart:math' as math;
 
 import 'generated/error.dart';
 import 'generated/source.dart';
@@ skipping 26 matching lines @@
 /// representation.
 class AnalyzerError implements Exception {
   final AnalysisError error;
 
   AnalyzerError(this.error);
 
   String get message => toString();
 
   String toString() {
     var builder = new StringBuffer();
-    var content = error.source.contents.data;
-    var beforeError = content.substring(0, error.offset);
-    var lineNumber = "\n".allMatches(beforeError).length + 1;
-    builder.writeln("Error on line $lineNumber of ${error.source.fullName}: "
-        "${error.message}");
 
-    var errorLineIndex = beforeError.lastIndexOf("\n") + 1;
-    var errorEndOfLineIndex = content.indexOf("\n", error.offset);
-    if (errorEndOfLineIndex == -1) errorEndOfLineIndex = content.length;
-    var errorLine = content.substring(
-        errorLineIndex, errorEndOfLineIndex);
-    var errorColumn = error.offset - errorLineIndex;
-    var errorLength = error.length;
+    // Print a less friendly string representation to ensure that
+    // error.source.contents is not executed, as .contents it isn't async
+    builder.writeln("Error in ${error.source.fullName}: ${error.message}");
 
-    // Ensure that the error line we display isn't too long.
-    if (errorLine.length > _MAX_ERROR_LINE_LENGTH) {
-      var leftLength = errorColumn;
-      var rightLength = errorLine.length - leftLength;
-      if (leftLength > _MAX_ERROR_LINE_LENGTH ~/ 2 &&
-          rightLength > _MAX_ERROR_LINE_LENGTH ~/ 2) {
-        errorLine = "..." + errorLine.substring(
-            errorColumn - _MAX_ERROR_LINE_LENGTH ~/ 2 + 3,
-            errorColumn + _MAX_ERROR_LINE_LENGTH ~/ 2 - 3)
-            + "...";
-        errorColumn = _MAX_ERROR_LINE_LENGTH ~/ 2;
-      } else if (rightLength > _MAX_ERROR_LINE_LENGTH ~/ 2) {
-        errorLine = errorLine.substring(0, _MAX_ERROR_LINE_LENGTH - 3) + "...";
-      } else {
-        assert(leftLength > _MAX_ERROR_LINE_LENGTH ~/ 2);
-        errorColumn -= errorLine.length - _MAX_ERROR_LINE_LENGTH;
-        errorLine = "..." + errorLine.substring(
-            errorLine.length - _MAX_ERROR_LINE_LENGTH + 3, errorLine.length);
-      }
-      errorLength = math.min(errorLength, _MAX_ERROR_LINE_LENGTH - errorColumn);
-    }
-    builder.writeln(errorLine);
+//    var content = error.source.contents.data;
+//    var beforeError = content.substring(0, error.offset);
+//    var lineNumber = "\n".allMatches(beforeError).length + 1;
+//    builder.writeln("Error on line $lineNumber of ${error.source.fullName}: "
+//        "${error.message}");
 
-    for (var i = 0; i < errorColumn; i++) builder.write(" ");
-    for (var i = 0; i < errorLength; i++) builder.write("^");
+//    var errorLineIndex = beforeError.lastIndexOf("\n") + 1;
+//    var errorEndOfLineIndex = content.indexOf("\n", error.offset);
+//    if (errorEndOfLineIndex == -1) errorEndOfLineIndex = content.length;
+//    var errorLine = content.substring(
+//        errorLineIndex, errorEndOfLineIndex);
+//    var errorColumn = error.offset - errorLineIndex;
+//    var errorLength = error.length;
+//
+//    // Ensure that the error line we display isn't too long.
+//    if (errorLine.length > _MAX_ERROR_LINE_LENGTH) {
+//      var leftLength = errorColumn;
+//      var rightLength = errorLine.length - leftLength;
+//      if (leftLength > _MAX_ERROR_LINE_LENGTH ~/ 2 &&
+//          rightLength > _MAX_ERROR_LINE_LENGTH ~/ 2) {
+//        errorLine = "..." + errorLine.substring(
+//            errorColumn - _MAX_ERROR_LINE_LENGTH ~/ 2 + 3,
+//            errorColumn + _MAX_ERROR_LINE_LENGTH ~/ 2 - 3)
+//            + "...";
+//        errorColumn = _MAX_ERROR_LINE_LENGTH ~/ 2;
+//      } else if (rightLength > _MAX_ERROR_LINE_LENGTH ~/ 2) {
+//        errorLine = errorLine.substring(0, _MAX_ERROR_LINE_LENGTH - 3) + "...";
+//      } else {
+//        assert(leftLength > _MAX_ERROR_LINE_LENGTH ~/ 2);
+//        errorColumn -= errorLine.length - _MAX_ERROR_LINE_LENGTH;
+//        errorLine = "..." + errorLine.substring(
+//            errorLine.length - _MAX_ERROR_LINE_LENGTH + 3, errorLine.length);
+//      }
+//      errorLength = math.min(errorLength, _MAX_ERROR_LINE_LENGTH - errorColumn);
+//    }
+//    builder.writeln(errorLine);
+//
+//    for (var i = 0; i < errorColumn; i++) builder.write(" ");
+//    for (var i = 0; i < errorLength; i++) builder.write("^");
     builder.writeln();
 
     return builder.toString();
   }
 }
 
 // A content receiver that collects all the content into a string.
 class _ContentReceiver implements Source_ContentReceiver {
   final _buffer = new StringBuffer();
 
   String get result => _buffer.toString();
 
   void accept(String contents, _) =>
     _buffer.write(contents.substring(0, contents.length));
 }