Remove AsyncError with Expando.

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 'dart:io';
 import 'dart:math';
@@ skipping 218 matching lines @@
     globalOptions = globalOptions_;
 
     try {
       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) {
+    handleError(error) {
+      var trace = getAttachedStackTrace(error);
+
       // This is basically the top-level exception handler so that we don't
       // spew a stack trace on our users.
       var message;
 
       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.
@@ skipping 20 matching lines @@
         // TODO(rnystrom): Will eventually need better logic to walk up
         // subdirectories until we hit one that looks package-like. For now,
         // just assume the cwd is it.
         entrypoint = new Entrypoint(path.current, cache);
       }
 
       var commandFuture = onRun();
       if (commandFuture == null) return true;
 
       return commandFuture;
-    }).whenComplete(() => cache_.deleteTempDir()).catchError((asyncError) {
-      var e = asyncError.error;
+    }).whenComplete(() => cache_.deleteTempDir()).catchError((e) {
       if (e is PubspecNotFoundException && e.name == null) {
         e = 'Could not find a file named "pubspec.yaml" in the directory '
           '${path.current}.';
       } else if (e is PubspecHasNoNameException && e.name == null) {
         e = 'pubspec.yaml is missing the required "name" field (e.g. "name: '
           '${path.basename(path.current)}").';
       }
 
-      handleError(e, asyncError.stackTrace);
+      handleError(e);
     }).then((_) {
       // Explicitly exit on success to ensure that any dangling dart:io handles
       // don't cause the process to never terminate.
       exit(0);
     });
   }
 
   /// Override this to perform the specific command. Return a future that
   /// completes when the command is done or fails if the command fails. If the
   /// command is synchronous, it may return `null`.
@@ skipping 21 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;
     }
   }
 }