Properly parse V8 stack traces that contain the exception description.

pkg/stack_trace/lib/src/trace.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 trace;
 
 import 'dart:collection';
 import 'dart:math' as math;
 
 import 'frame.dart';
 import 'lazy_trace.dart';
 import 'utils.dart';
 import 'vm_trace.dart';
 
 final _terseRegExp = new RegExp(r"(-patch)?(/.*)?$");
 
+/// A RegExp to match V8's stack traces.
+///
+/// V8's traces start with a line that's either just "Error" or else is a
+/// description of the exception that occurred. That description can be multiple
+/// lines, so we just look for any line other than the first that begins with
+/// four spaces and "at".
+final _v8Trace = new RegExp(r"\n    at ");
+
 /// A RegExp to match Firefox's stack traces.
 ///
 /// Firefox's trace frames start with the name of the function in which the
 /// error occurred, possibly including its parameters inside `()`. For example,
 /// `.VW.call$0("arg")@http://pub.dartlang.org/stuff.dart.js:560`.
 final _firefoxTrace = new RegExp(r"^([.0-9A-Za-z_$/<]|\(.*\))*@");
 
 /// A RegExp to match this package's stack traces.
 final _friendlyTrace = new RegExp(r"^[^\s]+( \d+:\d+)?\s+[^\s]+($|\n)");
 
@@ skipping 40 matching lines @@
     return new LazyTrace(() => new Trace.parse(trace.toString()));
   }
 
   /// Parses a string representation of a stack trace.
   ///
   /// [trace] should be formatted in the same way as a Dart VM or browser stack
   /// trace.
   factory Trace.parse(String trace) {
     try {
       if (trace.isEmpty) return new Trace(<Frame>[]);
-      if (trace.startsWith("Error\n")) return new Trace.parseV8(trace);
+      if (trace.contains(_v8Trace)) return new Trace.parseV8(trace);
       if (trace.contains(_firefoxTrace)) return new Trace.parseFirefox(trace);
       if (trace.contains(_friendlyTrace)) return new Trace.parseFriendly(trace);
 
       // Default to parsing the stack trace as a VM trace. This is also hit on
       // IE and Safari, where the stack trace is just an empty string (issue
       // 11257).
       return new Trace.parseVM(trace);
     } on FormatException catch (error) {
       throw new FormatException('${error.message}\nStack trace:\n$trace');
     }
   }
 
   /// Parses a string representation of a Dart VM stack trace.
   Trace.parseVM(String trace)
       : this(trace.trim().split("\n").map((line) => new Frame.parseVM(line)));
 
   /// Parses a string representation of a Chrome/V8 stack trace.
   Trace.parseV8(String trace)
-      : this(trace.split("\n").skip(1).map((line) => new Frame.parseV8(line)));
+      : this(trace.split("\n").skip(1)
+          // It's possible that an Exception's description contains a line that
+          // looks like a V8 trace line, which will screw this up.
+          // Unfortunately, that's impossible to detect.
+          .skipWhile((line) => !line.startsWith("    at "))
+          .map((line) => new Frame.parseV8(line)));
 
   /// Parses a string representation of a Firefox stack trace.
   Trace.parseFirefox(String trace)
       : this(trace.trim().split("\n")
           .map((line) => new Frame.parseFirefox(line)));
 
   /// Parses this package's a string representation of a stack trace.
   Trace.parseFriendly(String trace)
       : this(trace.trim().split("\n")
           .map((line) => new Frame.parseFriendly(line)));
@@ skipping 48 matching lines @@
     // Figure out the longest path so we know how much to pad.
     var longest = frames.map((frame) => frame.location.length)
         .fold(0, math.max);
 
     // Print out the stack trace nicely formatted.
     return frames.map((frame) {
       return '${padRight(frame.location, longest)}  ${frame.member}\n';
     }).join();
   }
 }