Fix path tests on windows.

utils/pub/pub.dart

 // Copyright (c) 2012, 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.
 
 /// The main entrypoint for the pub command line application.
 library pub;
 
 import 'dart:async';
 import '../../pkg/args/lib/args.dart';
 import '../../pkg/path/lib/path.dart' as path;
@@ skipping 217 matching lines @@
      commandOptions = commandParser.parse(commandArgs);
     } on FormatException catch (e) {
       log.error(e.message);
       log.error('Use "pub help" for more information.');
       exit(exit_codes.USAGE);
     }
 
     handleError(error, trace) {
       // This is basically the top-level exception handler so that we don't
       // spew a stack trace on our users.
-      var message = error.toString();
+      var message;
 
-      // TODO(rnystrom): The default exception implementation class puts
-      // "Exception:" in the output, so strip that off.
-      if (message.startsWith("Exception: ")) {
-        message = message.substring("Exception: ".length);
+      try {
+        // Most exception types have a "message" property. We prefer this since
+        // it skips the "Exception:", "HttpException:", etc. prefix that calling
+        // toString() adds. But, alas, "message" isn't actually defined in the
+        // base Exception type so there's no easy way to know if it's available
+        // short of a giant pile of type tests for each known exception type.
+        //
+        // So just try it. If it throws, default to toString().
+        message = error.message;
+      } on NoSuchMethodError catch (_) {
+        message = error.toString();
       }
 
       log.error(message);
       if (globalOptions['trace'] && trace != null) {
         log.error(trace);
         log.dumpTranscript();
       }
 
       exit(_chooseExitCode(error));
     }
@@ skipping 55 matching lines @@
     if (exception is HttpException || exception is HttpParserException ||
         exception is SocketIOException || exception is PubHttpException) {
       return exit_codes.UNAVAILABLE;
     } else if (exception is FormatException) {
       return exit_codes.DATA;
     } else {
       return 1;
     }
   }
 }