anchor.diff:                     lager:info("no metrics found in data directory '~s'", [Dir]);
                  true -> ok
               end,
  -            {[], 0}
  +            {?EMPTY_METRIC_DIR, 0}
       end.
   
   spawn_update_metrics(#state{status=pending}=State) ->
  
positive.code:          }).
  
  -record(metric_dir, {
            name :: nonempty_string(),
            metrics :: orddict:orddict(),
            dirs :: orddict:orddict()
           }).
  
  %%%===================================================================
  %%% API
  
negative.code: 
  new_metric_dir([Path], NewMetric) ->
      Name = NewMetric#metric_file.name,
      #metric_dir{name=Path,
                  metrics=orddict:from_list([{Name, NewMetric}]),
                  dirs=orddict:new()};
  
  new_metric_dir([Path | Paths], NewMetric) ->
      NewDir = new_metric_dir(Paths, NewMetric),
      Insert = [{NewDir#metric_dir.name, NewDir}],
      #metric_dir{name=Path,
                  metrics=orddict:new(),
                  dirs=orddict:from_list(Insert)}.
  
  
  find_metrics(Paths, Dir) ->
  