anchor.diff:  
           if (entry.isDirectory) {
             return walkFiles(entry, store).then((String sha) {
  -            if (sha != null) {return;
  +            if (sha != null) {
                 treeEntries.add(new TreeEntry(entry.name, shaToBytes(sha),
                     false));
               }
  
positive.code:           }
          }
  
          commitParts.add('author ${name} ');
          commitParts.add(' <$email> ');
          commitParts.add(dateString);
          commitParts.add('\n');
          commitParts.add('committer ${name}');
          commitParts.add(' <${email}>');
          commitParts.add(dateString);
          commitParts.add('\n\n${commitMsg}\n');
  
negative.code:       String refName) {
      chrome.DirectoryEntry dir = options.root;
      ObjectStore store = options.store;
      String username = options.username;
      String email = options.email;
      String commitMsg = options.commitMessage;
  
  