Don't extract the name of a package from its description.

utils/pub/system_cache.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('system_cache');
 
 #import('io.dart');
 #import('package.dart');
 #import('source.dart');
 #import('source_registry.dart');
@@ skipping 43 matching lines @@
    * Loads all of the package ids in the cache and returns them.
    */
   Future<List<PackageId>> listAll() {
     return listDir(rootDir).chain((paths) {
       final sources = paths.map((path) {
         final source = sources[basename(path)];
         return listDir(path).transform((subpaths) {
           // TODO(rnystrom): Once there are cached packages and this path is
           // being used, figure out how version numbers should be acquired.
           return subpaths.map((subpath) =>
-            new PackageId(source, Version.none, basename(subpath)));
+            new PackageId(
+                basename(subpath), source, Version.none, basename(subpath)));
         });
       });
       return Futures.wait(sources).transform(flatten);
     });
   }
 
   /**
    * Ensures that the package identified by [id] is installed to the cache,
    * loads it, and returns it.
    *
    * It is an error to try installing a package from a source with `shouldCache
    * == false` to the system cache.
    */
   Future<Package> install(PackageId id) {
     if (!id.source.shouldCache) {
       throw new IllegalArgumentException("Package $id is not cacheable.");
     }
 
     var pending = _pendingInstalls[id];
     if (pending != null) return pending;
 
     var future = id.source.installToSystemCache(id);
     always(future, () => _pendingInstalls.remove(id));
     _pendingInstalls[id] = future;
     return future;
   }
 }