Allow users of git cl to disable git copy detection entirely.

git_cl.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 # Copyright (C) 2008 Evan Martin <martine@danga.com>
 
 """A git-command for integrating reviews on Rietveld."""
 
 import json
@@ skipping 74 matching lines @@
 
 
 def ask_for_data(prompt):
   try:
     return raw_input(prompt)
   except KeyboardInterrupt:
     # Hide the exception.
     sys.exit(1)
 
 
+def git_set_branch_value(key, value):
+  branch = Changelist().GetBranch()
+  if branch:
+    git_key = 'branch.%s.%s' % (branch, key)
+    RunGit(['config', '--int', git_key, "%d" % value])
+
+
+def git_get_branch_default(key, default):
+  branch = Changelist().GetBranch()
+  if branch:
+    git_key = 'branch.%s.%s' % (branch, key)
+    (_, stdout) = RunGitWithCode(['config', '--int', '--get', git_key])
+    try:
+      return int(stdout.strip())
+    except ValueError:
+      pass
+  return default
+
+
 def add_git_similarity(parser):
   parser.add_option(
-      '--similarity', metavar='SIM', type='int', action='store', default=None,
+      '--similarity', metavar='SIM', type='int', action='store',
       help='Sets the percentage that a pair of files need to match in order to'
            ' be considered copies (default 50)')
+  parser.add_option(
+      '--find-copies', action='store_true',
+      help='Allows git to look for copies.')
+  parser.add_option(
+      '--no-find-copies', action='store_false', dest='find_copies',
+      help='Disallows git from looking for copies.')
 
   old_parser_args = parser.parse_args
   def Parse(args):
     options, args = old_parser_args(args)
 
-    branch = Changelist().GetBranch()
-    key = 'branch.%s.git-cl-similarity' % branch
     if options.similarity is None:
-      if branch:
-        (_, stdout) = RunGitWithCode(['config', '--int', '--get', key])
-        try:
-          options.similarity = int(stdout.strip())
-        except ValueError:
-          pass
-      options.similarity = options.similarity or 50
+      options.similarity = git_get_branch_default('git-cl-similarity', 50)
     else:
-      if branch:
-        print('Note: Saving similarity of %d%% in git config.'
-              % options.similarity)
-        RunGit(['config', '--int', key, str(options.similarity)])
+      print('Note: Saving similarity of %d%% in git config.'
+            % options.similarity)
+      git_set_branch_value('git-cl-similarity', options.similarity)
 
-    options.similarity = max(1, min(options.similarity, 100))
+    options.similarity = max(0, min(options.similarity, 100))
+
+    if options.find_copies is None:
+      options.find_copies = bool(
+          git_get_branch_default('git-find-copies', True))
+    else:
+      git_set_branch_value('git-find-copies', int(options.find_copies))
 
     print('Using %d%% similarity for rename/copy detection. '
           'Override with --similarity.' % options.similarity)
 
     return options, args
   parser.parse_args = Parse
 
 
 def MatchSvnGlob(url, base_url, glob_spec, allow_wildcards):
   """Return the corresponding git ref if |base_url| together with |glob_spec|
@@ skipping 30 matching lines @@
   # Parse specs like "trunk/src:refs/remotes/origin/trunk".
   if fetch_suburl:
     full_url = base_url + '/' + fetch_suburl
   else:
     full_url = base_url
   if full_url == url:
     return as_ref
   return None
 
 
-def print_stats(similarity, args):
+def print_stats(similarity, find_copies, args):
   """Prints statistics about the change to the user."""
   # --no-ext-diff is broken in some versions of Git, so try to work around
   # this by overriding the environment (but there is still a problem if the
   # git config key "diff.external" is used).
   env = os.environ.copy()
   if 'GIT_EXTERNAL_DIFF' in env:
     del env['GIT_EXTERNAL_DIFF']
+
+  if find_copies:
+    similarity_options = ['--find-copies-harder', '-l100000',
+                          '-C%s' % similarity]
+  else:
+    similarity_options = ['-M%s' % similarity]
+
   return subprocess2.call(
-      ['git', 'diff', '--no-ext-diff', '--stat', '--find-copies-harder',
-       '-C%s' % similarity, '-l100000'] + args, env=env)
+      ['git', 'diff', '--no-ext-diff', '--stat'] + similarity_options + args,
+      env=env)
 
 
 class Settings(object):
   def __init__(self):
     self.default_server = None
     self.cc = None
     self.root = None
     self.is_git_svn = None
     self.svn_branch = None
     self.tree_status_url = None
@@ skipping 873 matching lines @@
       upload_args.extend(['--reviewers', change_desc.reviewers])
     if options.send_mail:
       if not change_desc.reviewers:
         DieWithError("Must specify reviewers to send email.")
       upload_args.append('--send_mail')
     cc = ','.join(filter(None, (cl.GetCCList(), options.cc)))
     if cc:
       upload_args.extend(['--cc', cc])
 
   upload_args.extend(['--git_similarity', str(options.similarity)])
+  if not options.find_copies:
+    upload_args.extend(['--git_no_find_copies'])
 
   # Include the upstream repo's URL in the change -- this is useful for
   # projects that have their source spread across multiple repos.
   remote_url = cl.GetGitBaseUrlFromConfig()
   if not remote_url:
     if settings.GetIsGitSvn():
       # URL is dependent on the current directory.
       data = RunGit(['svn', 'info'], cwd=settings.GetRoot())
       if data:
         keys = dict(line.split(': ', 1) for line in data.splitlines()
@@ skipping 83 matching lines @@
   if not options.bypass_hooks:
     hook_results = cl.RunHook(committing=False, upstream_branch=base_branch,
                               may_prompt=not options.force,
                               verbose=options.verbose,
                               author=None)
     if not hook_results.should_continue():
       return 1
     if not options.reviewers and hook_results.reviewers:
       options.reviewers = hook_results.reviewers
 
-  print_stats(options.similarity, args)
+  print_stats(options.similarity, options.find_copies, args)
   if settings.GetIsGerrit():
     return GerritUpload(options, args, cl)
   return RietveldUpload(options, args, cl)
 
 
 def IsSubmoduleMergeCommit(ref):
   # When submodules are added to the repo, we expect there to be a single
   # non-git-svn merge commit at remote HEAD with a signature comment.
   pattern = '^SVN changes up to revision [0-9]*$'
   cmd = ['rev-list', '--merges', '--grep=%s' % pattern, '%s^!' % ref]
@@ skipping 113 matching lines @@
 
   if cl.GetIssue():
     description += "\n\nReview URL: %s" % cl.GetIssueURL()
 
   if options.contributor:
     description += "\nPatch from %s." % options.contributor
   print 'Description:', repr(description)
 
   branches = [base_branch, cl.GetBranchRef()]
   if not options.force:
-    print_stats(options.similarity, branches)
+    print_stats(options.similarity, options.find_copies, branches)
     ask_for_data('About to commit; enter to confirm.')
 
   # We want to squash all this branch's commits into one commit with the proper
   # description. We do this by doing a "reset --soft" to the base branch (which
   # keeps the working copy the same), then dcommitting that.  If origin/master
   # has a submodule merge commit, we'll also need to cherry-pick the squashed
   # commit onto a branch based on the git-svn head.
   MERGE_BRANCH = 'git-cl-commit'
   CHERRY_PICK_BRANCH = 'git-cl-cherry-pick'
   # Delete the branches if they exist.
@@ skipping 434 matching lines @@
              'and retry or visit go/isgaeup.\n%s') % (e.code, str(e)))
 
   # Not a known command. Default to help.
   GenUsage(parser, 'help')
   return CMDhelp(parser, argv)
 
 
 if __name__ == '__main__':
   fix_encoding.fix_encoding()
   sys.exit(main(sys.argv[1:]))