@Override
  protected Map<String, Void> performIndexing(IdeaPlugin plugin) {
    List<String> ids = new ArrayList<>();
    ids.add(StringUtil.notNullize(plugin.getPluginId()));
    for (DomElement module : getChildrenWithoutIncludes(plugin, "module")) {
      ContainerUtil.addIfNotNull(ids, ((PluginModule)module).getValue().getStringValue());
    }
    return ContainerUtil.newHashMap(ids, Collections.nCopies(ids.size(), null));
  }
@Override
  protected Map<String, Void> performIndexing(IdeaPlugin plugin)