Removing the mutation in the factories for getting dep repositories

appengine/findit/common/chrome_dependency_fetcher.py

 # Copyright 2014 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.
 
 import re
 
 from common import dependency
 from common import deps_parser
 
 _CHROMIUM_ROOT_DIR = 'src/'
 _CHROMIUM_REPO_MASTER = 'https://chromium.googlesource.com/chromium/src.git'
 
 _CHROME_VERSION_PATTERN = re.compile(r'^\d+\.\d+\.\d+\.\d+$')
 
 _BUILDSPEC_REPO = ('https://chrome-internal.googlesource.com/chrome/tools/'
                    'buildspec.git/')
 
 
 def IsChromeVersion(revision):
   """Determines if a revision is a chrome version."""
-  if _CHROME_VERSION_PATTERN.match(revision):
-    return True
-
-  return False
+  return bool(_CHROME_VERSION_PATTERN.match(revision))
 
 
 class DEPSDownloader(deps_parser.DEPSLoader):
   """Downloads DEPS from remote Git repo."""
 
-  def __init__(self, repository):
-    self.repository = repository
+  def __init__(self, get_repository):
+    assert callable(get_repository), (
+        'The ``get_repository`` argument must be callable.')
+    self._get_repository = get_repository
 
   def Load(self, repo_url, revision, deps_file):
-    self.repository.repo_url = repo_url
+    repository = self._get_repository(repo_url)
     content = None
     if deps_file == 'DEPS' and repo_url == _CHROMIUM_REPO_MASTER:
       # Try .DEPS.git instead of DEPS first, for commits during the Git chaos.
-      content = self.repository.GetSource('.DEPS.git', revision)
+      content = repository.GetSource('.DEPS.git', revision)
 
     if content is None:
-      content = self.repository.GetSource(deps_file, revision)
+      content = repository.GetSource(deps_file, revision)
 
     if content is None and deps_file != 'DEPS':
       # Like gclient, fall back to raw 'DEPS' when all else fails.
-      content = self.repository.GetSource('DEPS', revision)
+      content = repository.GetSource('DEPS', revision)
 
     if content is None:
       raise Exception(
           'Failed to pull %s file from %s, at revision %s.' % (
               deps_file, repo_url, revision))
 
     return content
 
 
 class ChromeDependencyFetcher(object):
 
-  def __init__(self, repository):
-    self.repository = repository
+  def __init__(self, get_repository):
+    assert callable(get_repository), (
+        'The ``get_repository`` argument must be callable.')
+    self._get_repository = get_repository
 
   def GetDependency(self, revision, platform):
     """Returns all dependencies of Chrome as a dict for given revision and OS.
 
     Args:
       revision (str): The revision of a Chrome build, it can be a githash or a
         chrome version for a official build.
       platform (str): The target platform of the Chrome build, should be one of
         'win', 'ios', 'mac', 'unix', 'android', or 'all'.
 
     Returns:
       A map from dependency path to the dependency info.
     """
     deps_repo_info = {'deps_file': 'DEPS'}
 
     if IsChromeVersion(revision):
       # For chrome version, get the DEPS file from internal buildspec/ repo
       # instead of chromium trunk.
       deps_repo_info['deps_repo_url'] = _BUILDSPEC_REPO
       deps_repo_info['deps_repo_revision'] = 'master'
       deps_repo_info['deps_file'] = 'releases/%s/DEPS' % revision
 
     root_dep = dependency.Dependency(
         _CHROMIUM_ROOT_DIR, _CHROMIUM_REPO_MASTER, revision, **deps_repo_info)
 
     deps_parser.UpdateDependencyTree(
-        root_dep, [platform], DEPSDownloader(self.repository))
+        root_dep, [platform], DEPSDownloader(self._get_repository))
 
     dependencies = {}
 
     # Flatten the dependency tree into a one-level dict.
     def FlattenDepTree(dep):
       dependencies[dep.path] = dep
       for child in dep.children.values():
         FlattenDepTree(child)
 
     FlattenDepTree(root_dep)
@@ skipping 62 matching lines @@
     """
     deps_rolls = self.GetDependencyRolls(old_cr_revision, new_cr_revision,
                                          platform, skip_chromium_roll=False)
 
     deps_rolls_dict = {}
 
     for dep_roll in deps_rolls:
       deps_rolls_dict[dep_roll.path] = dep_roll
 
     return deps_rolls_dict