Automatically guess Gerrit change number in "repo upload --replace"

This feature only works if you have one commit to replace right now
(the common case).

git_config.py

@@ -337,19 +337,16 @@ class RefSpec(object):
 _ssh_cache = {}
 _ssh_master = True
 
-def _open_ssh(host, port=None):
+def _open_ssh(host, port):
   global _ssh_master
 
-  if port is None:
-    port = 22
-
   key = '%s:%s' % (host, port)
   if key in _ssh_cache:
     return True
 
   if not _ssh_master \
   or 'GIT_SSH' in os.environ \
-  or sys.platform == 'win32':
+  or sys.platform in ('win32', 'cygwin'):
     # failed earlier, or cygwin ssh can't do this
     #
     return False
@@ -388,7 +385,7 @@ def close_ssh():
       pass
 
 URI_SCP = re.compile(r'^([^@:]*@?[^:/]{1,}):')
-URI_ALL = re.compile(r'^([a-z][a-z+]*)://([^@/]*@?[^/])/')
+URI_ALL = re.compile(r'^([a-z][a-z+]*)://([^@/]*@?[^/]*)/')
 
 def _preconnect(url):
   m = URI_ALL.match(url)
@@ -397,6 +394,8 @@ def _preconnect(url):
     host = m.group(2)
     if ':' in host:
       host, port = host.split(':')
+    else:
+      port = 22
     if scheme in ('ssh', 'git+ssh', 'ssh+git'):
       return _open_ssh(host, port)
     return False
@@ -404,7 +403,7 @@ def _preconnect(url):
   m = URI_SCP.match(url)
   if m:
     host = m.group(1)
-    return _open_ssh(host)
+    return _open_ssh(host, 22)
 
 
 class Remote(object):

project.py

@@ -155,6 +155,19 @@ class ReviewableBranch(object):
                                  self.replace_changes,
                                  people)
 
+  def GetPublishedRefs(self):
+    refs = {}
+    output = self.project.bare_git.ls_remote(
+      self.branch.remote.SshReviewUrl(self.project.UserEmail),
+      'refs/changes/*')
+    for line in output.split('\n'):
+      try:
+        (sha, ref) = line.split()
+        refs[sha] = ref
+      except ValueError:
+        pass
+
+    return refs
 
 class StatusColoring(Coloring):
   def __init__(self, config):

subcmds/start.py

@@ -22,13 +22,18 @@ class Start(Command):
   common = True
   helpSummary = "Start a new branch for development"
   helpUsage = """
-%prog <newbranchname> [<project>...]
+%prog <newbranchname> [--all | <project>...]
 """
   helpDescription = """
 '%prog' begins a new branch of development, starting from the
 revision specified in the manifest.
 """
 
+  def _Options(self, p):
+    p.add_option('--all',
+                 dest='all', action='store_true',
+                 help='begin branch in all projects')
+
   def Execute(self, opt, args):
     if not args:
       self.Usage()
@@ -39,7 +44,14 @@ revision specified in the manifest.
       sys.exit(1)
 
     err = []
-    all = self.GetProjects(args[1:])
+    projects = []
+    if not opt.all:
+      projects = args[1:]
+      if len(projects) < 1:
+        print >>sys.stderr, "error: at least one project must be specified"
+        sys.exit(1)
+
+    all = self.GetProjects(projects)
 
     pm = Progress('Starting %s' % nb, len(all))
     for project in all:

subcmds/upload.py

@@ -194,6 +194,18 @@ Gerrit Code Review:  http://code.google.com/p/gerrit/
       _die("nothing uncommented for upload")
     self._UploadAndReport(todo, people)
 
+  def _FindGerritChange(self, branch):
+    last_pub = branch.project.WasPublished(branch.name)
+    if last_pub is None:
+      return ""
+
+    refs = branch.GetPublishedRefs()
+    try:
+      # refs/changes/XYZ/N --> XYZ
+      return refs.get(last_pub).split('/')[-2]
+    except:
+      return ""
+
   def _ReplaceBranch(self, project, people):
     branch = project.CurrentBranch
     if not branch:
@@ -206,8 +218,14 @@ Gerrit Code Review:  http://code.google.com/p/gerrit/
 
     script = []
     script.append('# Replacing from branch %s' % branch.name)
+
+    if len(branch.commits) == 1:
+      change = self._FindGerritChange(branch)
+      script.append('[%-6s] %s' % (change, branch.commits[0]))
+    else:
       for commit in branch.commits:
         script.append('[      ] %s' % commit)
+
     script.append('')
     script.append('# Insert change numbers in the brackets to add a new patch set.')
     script.append('# To create a new change record, leave the brackets empty.')