Removing the mutation in the factories for getting dep repositories

appengine/findit/util_scripts/crash_queries/delta_test/delta_util.py

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Util functions for git repository processing for delta test."""
 
 import base64
 import hashlib
 import json
 import logging
@@ skipping 38 matching lines @@
         ['git', 'rev-parse', revision]).replace('\n', '')
   except: # pylint: disable=W
     logging.error('Failed to parse git hash for %s\nStacktrace:\n%s',
                   revision, traceback.format_exc())
     return None
 
 
 # TODO(crbug.com/662540): Add unittests.
 def EnsureDirExists(path):  # pragma: no cover
   directory = os.path.dirname(path)
+  # TODO: this has a race condition. Should ``try: os.makedirs`` instead,
+  # discarding the error and returning if the directory already exists.
   if os.path.exists(directory):
     return
 
   os.makedirs(directory)
 
 
 # TODO(crbug.com/662540): Add unittests.
 def FlushResult(result, result_path, serializer=pickle):  # pragma: no cover
   print '\nFlushing results to', result_path
   EnsureDirExists(result_path)
@@ skipping 31 matching lines @@
     for crash_id, delta in deltas.iteritems():
       delta_str_dict = delta.delta_str_dict
       feedback_url = _FRACAS_FEEDBACK_URL_TEMPLATE % (app_id, crash_id)
       f.write('%s, "%s", "%s", "%s", "%s"\n' % (
           feedback_url,
           _EncodeStr(delta_str_dict.get('suspected_project', '')),
           _EncodeStr(delta_str_dict.get('suspected_components', '')),
           _EncodeStr(delta_str_dict.get('suspected_cls', '')),
           _EncodeStr(delta_str_dict.get('regression_range', ''))
       ))