Unwrap AsyncErrors to find real error.

utils/pub/hosted_source.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.
 
 library hosted_source;
 
 import 'dart:async';
 import 'dart:io' as io;
 import 'dart:json' as json;
 import 'dart:uri';
@@ skipping 101 matching lines @@
   /// given name from the default host, while a map with keys "name" and "url"
   /// refers to a package with the given name from the host at the given URL.
   void validateDescription(description, {bool fromLockFile: false}) {
     _parseDescription(description);
   }
 
   /// When an error occurs trying to read something about [package] from [url],
   /// this tries to translate into a more user friendly error message. Always
   /// throws an error, either the original one or a better one.
   void _throwFriendlyError(ex, package, url) {
+    ex = getRealError(ex);
+
     if (ex is PubHttpException && ex.response.statusCode == 404) {
       throw 'Could not find package "$package" at $url.';
     }
 
     if (ex is TimeoutException) {
       throw 'Timed out trying to find package "$package" at $url.';
     }
 
     if (ex is io.SocketIOException) {
       throw 'Got socket error trying to find package "$package" at $url.\n'
@@ skipping 25 matching lines @@
 
     var name = description["name"];
     if (name is! String) {
       throw new FormatException("The 'name' key must have a string value.");
     }
 
     var url = description.containsKey("url") ? description["url"] : defaultUrl;
     return new Pair<String, String>(name, url);
   }
 }