anchor.diff:      return objectStore.then((store) {
         GitOptions options = new GitOptions(root: entry, store: store);
         Fetch fetch = new Fetch(new GitOptions(root: entry, store: store));
  -      return fetch.fetch();
  +      return fetch.fetch().catchError((e) => SparkException.fromException(e));
       });
     }
   
  
positive.code:           name: userName, email: userEmail);
        return Commit.commit(options).then((_) {
          _refreshStatus(project: project);
        });
      });
    }
  
  
negative.code:     return objectStore.then((store) {
        GitOptions options = new GitOptions(root: entry, store: store,
            username: username, password: password);
        return Push.push(options).catchError(
            (e) => SparkException.fromException(e));
      });
    }
  
  