Expand git-footers to read the svn position for any trunk path in any repo.

git_footers.py

 #!/usr/bin/env python
 # 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 argparse
 import re
 import sys
 
 from collections import defaultdict
@@ skipping 39 matching lines @@
   key = normalize_name(key)
   values = footers[key]
   assert len(values) <= 1, 'Multiple %s footers' % key
   if values:
     return values[0]
   else:
     return None
 
 
 def get_position(footers):
-  """Get the chrome commit position from a footer multimap using a heuristic.
+  """Get the commit position from the footers multimap using a heuristic.
 
   Returns:
     A tuple of the branch and the position on that branch. For example,
 
     Cr-Commit-Position: refs/heads/master@{#292272}
 
     would give the return value ('refs/heads/master', 292272).  If
     Cr-Commit-Position is not defined, we try to infer the ref and position
     from git-svn-id. The position number can be None if it was not inferrable.
   """
 
   position = get_unique(footers, 'Cr-Commit-Position')
   if position:
     match = CHROME_COMMIT_POSITION_PATTERN.match(position)
     assert match, 'Invalid Cr-Commit-Position value: %s' % position
     return (match.group(1), match.group(2))
 
   svn_commit = get_unique(footers, 'git-svn-id')
   if svn_commit:
     match = GIT_SVN_ID_PATTERN.match(svn_commit)
     assert match, 'Invalid git-svn-id value: %s' % svn_commit
-    if re.match('.*/chrome/trunk/src$', match.group(1)):
+    # Assume that any trunk svn revision will match the commit-position
+    # semantics.
+    if re.match('.*/trunk/.*$', match.group(1)):
       return ('refs/heads/master', match.group(2))
+
+    # But for now only support faking branch-heads for chrome.
     branch_match = re.match('.*/chrome/branches/([\w/-]+)/src$', match.group(1))
     if branch_match:
       # svn commit numbers do not map to branches.
       return ('refs/branch-heads/%s' % branch_match.group(1), None)
 
   raise ValueError('Unable to infer commit position from footers')
 
 
 def main(args):
   parser = argparse.ArgumentParser(
@@ skipping 28 matching lines @@
     assert pos[1], 'No valid position for commit'
     print pos[1]
   else:
     for k in footers.keys():
       for v in footers[k]:
         print '%s: %s' % (k, v)
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))