Support --target-branch option to git-cl upload for Rietveld

git_cl.py

Index: git_cl.py
diff --git a/git_cl.py b/git_cl.py
index b23923681ba3b0ed094f99bd3239aec3ddf58e4b..c405e9f77a9882abd5d37f530330b03db77ff9a3 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -1679,6 +1679,57 @@ def GerritUpload(options, args, cl, change):
   return 0
 
 
+def GetTargetRef(remote, remote_branch, target_branch, pending_prefix):
+  """Computes the remote branch given the remote and remote branch state from

[agable, 2015/01/26 17:37:03]

nit: Docstring style is 

"""Single line description.

More multi-line description
if necessary.

Args:
  argument (type): description
  otherargument (type): other description
"""

[Mike Wittman, 2015/01/26 19:31:08]

Done.

+  the CL, the user's specified target branch (if any), and the pending prefix.
+  """
+  if not (remote and remote_branch):
+    return None
+  
+  if target_branch:
+    # Cannonicalize branch references to the equivalent local full symbolic
+    # refs, which are then translated into the remote full symbolic refs
+    # below.
+    if '/' not in target_branch:
+      remote_branch = 'refs/remotes/%s/%s' % (remote, target_branch)
+    else:
+      prefix_replacements = (
+        ('^((refs/)?remotes/)?branch-heads/', 'refs/remotes/branch-heads/'),
+        ('^((refs/)?remotes/)?%s/' % remote,  'refs/remotes/%s/' % remote),
+        ('^(refs/)?heads/',                   'refs/remotes/%s/' % remote),
+      )
+      match = None
+      for regex, replacement in prefix_replacements:
+        match = re.search(regex, target_branch)
+        if match:
+          remote_branch = target_branch.replace(match.group(0), replacement)
+          break
+      if not match:
+        # This is a branch path but not one we recognize; use as-is.
+        remote_branch = target_branch
+  elif (not remote_branch.startswith('refs/remotes/branch-heads') and
+        not remote_branch.startswith('refs/remotes/%s/refs' % remote)):
+    # Default to master for refs that are not branches.
+    remote_branch = 'refs/remotes/%s/master' % remote
+    
+  # Create the true path to the remote branch.
+  # Does the following translation:
+  # * refs/remotes/origin/refs/diff/test -> refs/diff/test
+  # * refs/remotes/origin/master -> refs/heads/master
+  # * refs/remotes/branch-heads/test -> refs/branch-heads/test
+  if remote_branch.startswith('refs/remotes/%s/refs/' % remote):
+    remote_branch = remote_branch.replace('refs/remotes/%s/' % remote, '')
+  elif remote_branch.startswith('refs/remotes/%s/' % remote):
+    remote_branch = remote_branch.replace('refs/remotes/%s/' % remote,
+                                          'refs/heads/')
+  elif remote_branch.startswith('refs/remotes/branch-heads'):
+    remote_branch = remote_branch.replace('refs/remotes/', 'refs/')
+  # If a pending prefix exists then replace refs/ with it.
+  if pending_prefix:
+    remote_branch = remote_branch.replace('refs/', pending_prefix)
+  return remote_branch
+
+
 def RietveldUpload(options, args, cl, change):
   """upload the patch to rietveld."""
   upload_args = ['--assume_yes']  # Don't ask about untracked files.
@@ -1757,24 +1808,10 @@ def RietveldUpload(options, args, cl, change):
   if remote_url:
     upload_args.extend(['--base_url', remote_url])
     remote, remote_branch = cl.GetRemoteBranch()
-    if remote and remote_branch:
-      # Create the true path to the remote branch.
-      # Does the following translation:
-      # * refs/remotes/origin/refs/diff/test -> refs/diff/test
-      # * refs/remotes/origin/master -> refs/heads/master
-      # * refs/remotes/branch-heads/test -> refs/branch-heads/test
-      if remote_branch.startswith('refs/remotes/%s/refs/' % remote):
-        remote_branch = remote_branch.replace('refs/remotes/%s/' % remote, '')
-      elif remote_branch.startswith('refs/remotes/%s/' % remote):
-        remote_branch = remote_branch.replace('refs/remotes/%s/' % remote,
-                                              'refs/heads/')
-      elif remote_branch.startswith('refs/remotes/branch-heads'):
-        remote_branch = remote_branch.replace('refs/remotes/', 'refs/')
-      pending_prefix = settings.GetPendingRefPrefix()
-      # If a pending prefix exists then replace refs/ with it.
-      if pending_prefix:
-        remote_branch = remote_branch.replace('refs/', pending_prefix)
-      upload_args.extend(['--target_ref', remote_branch])
+    target_ref = GetTargetRef(remote, remote_branch, options.target_branch,
+                              settings.GetPendingRefPrefix())
+    if target_ref:
+      upload_args.extend(['--target_ref', target_ref])
 
   project = settings.GetProject()
   if project:
@@ -1851,8 +1888,9 @@ def CMDupload(parser, args):
                     help='set the review private (rietveld only)')
   parser.add_option('--target_branch',
                     '--target-branch',
-                    help='When uploading to gerrit, remote branch to '
-                         'use for CL.  Default: master')
+                    metavar='TARGET',
+                    help='Apply CL to remote ref TARGET.  ' +
+                         'Default: remote branch head, or master')
   parser.add_option('--email', default=None,
                     help='email address to use to connect to Rietveld')
   parser.add_option('--tbr-owners', dest='tbr_owners', action='store_true',
@@ -1861,9 +1899,6 @@ def CMDupload(parser, args):
   add_git_similarity(parser)
   (options, args) = parser.parse_args(args)
 
-  if options.target_branch and not settings.GetIsGerrit():
-    parser.error('Use --target_branch for non gerrit repository.')
-
   if is_dirty_git_tree('upload'):
     return 1