Use class-level variable instead of instance members for Change object.

presubmit_support.py

 #!/usr/bin/env python
 # Copyright (c) 2011 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.
 
 """Enables directory-specific presubmit checks to run at upload and/or commit.
 """
 
 __version__ = '1.6.1'
 
@@ skipping 608 matching lines @@
         self._is_text_file = False
       elif self.IsDirectory():
         self._is_text_file = False
       else:
         self._is_text_file = os.path.isfile(self.AbsoluteLocalPath())
     return self._is_text_file
 
   def GenerateScmDiff(self):
     return scm.GIT.GenerateDiff(self._local_root, files=[self.LocalPath(),])
 
+
 class Change(object):
   """Describe a change.
 
   Used directly by the presubmit scripts to query the current change being
   tested.
 
   Instance members:
     tags: Dictionnary of KEY=VALUE pairs found in the change description.
     self.KEY: equivalent to tags['KEY']
   """
 
   _AFFECTED_FILES = AffectedFile
 
   # Matches key/value (or "tag") lines in changelist descriptions.
   _TAG_LINE_RE = re.compile(
       '^\s*(?P<key>[A-Z][A-Z_0-9]*)\s*=\s*(?P<value>.*?)\s*$')
+  scm = ''
 
   def __init__(self, name, description, local_root, files, issue, patchset):
     if files is None:
       files = []
     self._name = name
     self._full_description = description
     # Convert root into an absolute path.
     self._local_root = os.path.abspath(local_root)
     self.issue = issue
     self.patchset = patchset
-    self.scm = ''
 
     # From the description text, build up a dictionary of key/value pairs
     # plus the description minus all key/value or "tag" lines.
     description_without_tags = []
     self.tags = {}
     for line in self._full_description.splitlines():
       m = self._TAG_LINE_RE.match(line)
       if m:
         self.tags[m.group('key')] = m.group('value')
       else:
@@ skipping 93 matching lines @@
         integer line number (1-based); and
         the contents of the line as a string.
     """
     return _RightHandSideLinesImpl(
         x for x in self.AffectedFiles(include_deletes=False)
         if x.IsTextFile())
 
 
 class SvnChange(Change):
   _AFFECTED_FILES = SvnAffectedFile
-
-  def __init__(self, *args, **kwargs):
-    Change.__init__(self, *args, **kwargs)
-    self.scm = 'svn'
-    self._changelists = None
+  scm = 'svn'
+  _changelists = None
 
   def _GetChangeLists(self):
     """Get all change lists."""
     if self._changelists == None:
       previous_cwd = os.getcwd()
       os.chdir(self.RepositoryRoot())
       # Need to import here to avoid circular dependency.
       import gcl
       self._changelists = gcl.GetModifiedFiles()
       os.chdir(previous_cwd)
@@ skipping 10 matching lines @@
 
   def GetModifiedFiles(self):
     """Get modified files in the current CL."""
     changelists = self._GetChangeLists()
     return [os.path.join(self.RepositoryRoot(), f[1])
             for f in changelists[self.Name()]]
 
 
 class GitChange(Change):
   _AFFECTED_FILES = GitAffectedFile
-
-  def __init__(self, *args, **kwargs):
-    Change.__init__(self, *args, **kwargs)
-    self.scm = 'git'
+  scm = 'git'
 
 
 def ListRelevantPresubmitFiles(files, root):
   """Finds all presubmit files that apply to a given set of source files.
 
   If inherit-review-settings-ok is present right under root, looks for
   PRESUBMIT.py in directories enclosing root.
 
   Args:
     files: An iterable container containing file paths.
@@ skipping 387 matching lines @@
   except PresubmitFailure, e:
     print >> sys.stderr, e
     print >> sys.stderr, 'Maybe your depot_tools is out of date?'
     print >> sys.stderr, 'If all fails, contact maruel@'
     return 2
 
 
 if __name__ == '__main__':
   fix_encoding.fix_encoding()
   sys.exit(Main(None))