Move git-cl into depot_tools....

git_cl/git_cl.py

Index: git_cl/git_cl.py
===================================================================
--- git_cl/git_cl.py	(revision 0)
+++ git_cl/git_cl.py	(revision 0)
@@ -0,0 +1,1254 @@
+#!/usr/bin/python
+# git-cl -- a git-command for integrating reviews on Rietveld
+# Copyright (C) 2008 Evan Martin <martine@danga.com>
+
+import errno
+import logging
+import optparse
+import os
+import re
+import subprocess
+import sys
+import tempfile
+import textwrap
+import upload
+import urllib2
+
+try:
+  import readline
+except ImportError:
+  pass
+
+try:
+  # Add the parent directory in case it's a depot_tools checkout.
+  depot_tools_path = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+  sys.path.append(depot_tools_path)
+  import breakpad
+except ImportError:
+  pass
+
+DEFAULT_SERVER = 'http://codereview.appspot.com'
+PREDCOMMIT_HOOK = '.git/hooks/pre-cl-dcommit'
+PREUPLOAD_HOOK = '.git/hooks/pre-cl-upload'
+DESCRIPTION_BACKUP_FILE = '~/.git_cl_description_backup'
+
+def DieWithError(message):
+  print >>sys.stderr, message
+  sys.exit(1)
+
+
+def Popen(cmd, **kwargs):
+  """Wrapper for subprocess.Popen() that logs and watch for cygwin issues"""
+  logging.info('Popen: ' + ' '.join(cmd))
+  try:
+    return subprocess.Popen(cmd, **kwargs)
+  except OSError, e:
+    if e.errno == errno.EAGAIN and sys.platform == 'cygwin':
+      DieWithError(
+          'Visit '
+          'http://code.google.com/p/chromium/wiki/CygwinDllRemappingFailure to '
+          'learn how to fix this error; you need to rebase your cygwin dlls')
+    raise
+
+
+def RunCommand(cmd, error_ok=False, error_message=None,
+               redirect_stdout=True, swallow_stderr=False):
+  if redirect_stdout:
+    stdout = subprocess.PIPE
+  else:
+    stdout = None
+  if swallow_stderr:
+    stderr = subprocess.PIPE
+  else:
+    stderr = None
+  proc = Popen(cmd, stdout=stdout, stderr=stderr)
+  output = proc.communicate()[0]
+  if not error_ok and proc.returncode != 0:
+    DieWithError('Command "%s" failed.\n' % (' '.join(cmd)) +
+                 (error_message or output or ''))
+  return output
+
+
+def RunGit(args, **kwargs):
+  cmd = ['git'] + args
+  return RunCommand(cmd, **kwargs)
+
+
+def RunGitWithCode(args):
+  proc = Popen(['git'] + args, stdout=subprocess.PIPE)
+  output = proc.communicate()[0]
+  return proc.returncode, output
+
+
+def usage(more):
+  def hook(fn):
+    fn.usage_more = more
+    return fn
+  return hook
+
+
+def FixUrl(server):
+  """Fix a server url to defaults protocol to http:// if none is specified."""
+  if not server:
+    return server
+  if not re.match(r'[a-z]+\://.*', server):
+    return 'http://' + server
+  return server
+
+
+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
+    self.viewvc_url = None
+    self.updated = False
+
+  def LazyUpdateIfNeeded(self):
+    """Updates the settings from a codereview.settings file, if available."""
+    if not self.updated:
+      cr_settings_file = FindCodereviewSettingsFile()
+      if cr_settings_file:
+        LoadCodereviewSettingsFromFile(cr_settings_file)
+      self.updated = True
+
+  def GetDefaultServerUrl(self, error_ok=False):
+    if not self.default_server:
+      self.LazyUpdateIfNeeded()
+      self.default_server = FixUrl(self._GetConfig('rietveld.server',
+                                                   error_ok=True))
+      if error_ok:
+        return self.default_server
+      if not self.default_server:
+        error_message = ('Could not find settings file. You must configure '
+                         'your review setup by running "git cl config".')
+        self.default_server = FixUrl(self._GetConfig(
+            'rietveld.server', error_message=error_message))
+    return self.default_server
+
+  def GetCCList(self):
+    """Return the users cc'd on this CL.
+
+    Return is a string suitable for passing to gcl with the --cc flag.
+    """
+    if self.cc is None:
+      self.cc = self._GetConfig('rietveld.cc', error_ok=True)
+      more_cc = self._GetConfig('rietveld.extracc', error_ok=True)
+      if more_cc is not None:
+        self.cc += ',' + more_cc
+    return self.cc
+
+  def GetRoot(self):
+    if not self.root:
+      self.root = os.path.abspath(RunGit(['rev-parse', '--show-cdup']).strip())
+    return self.root
+
+  def GetIsGitSvn(self):
+    """Return true if this repo looks like it's using git-svn."""
+    if self.is_git_svn is None:
+      # If you have any "svn-remote.*" config keys, we think you're using svn.
+      self.is_git_svn = RunGitWithCode(
+          ['config', '--get-regexp', r'^svn-remote\.'])[0] == 0
+    return self.is_git_svn
+
+  def GetSVNBranch(self):
+    if self.svn_branch is None:
+      if not self.GetIsGitSvn():
+        DieWithError('Repo doesn\'t appear to be a git-svn repo.')
+
+      # Try to figure out which remote branch we're based on.
+      # Strategy:
+      # 1) find all git-svn branches and note their svn URLs.
+      # 2) iterate through our branch history and match up the URLs.
+
+      # regexp matching the git-svn line that contains the URL.
+      git_svn_re = re.compile(r'^\s*git-svn-id: (\S+)@', re.MULTILINE)
+
+      # Get the refname and svn url for all refs/remotes/*.
+      remotes = RunGit(['for-each-ref', '--format=%(refname)',
+                        'refs/remotes']).splitlines()
+      svn_refs = {}
+      for ref in remotes:
+        match = git_svn_re.search(RunGit(['cat-file', '-p', ref]))
+        # Prefer origin/HEAD over all others.
+        if match and (match.group(1) not in svn_refs or
+                      ref == "refs/remotes/origin/HEAD"):
+          svn_refs[match.group(1)] = ref
+
+      if len(svn_refs) == 1:
+        # Only one svn branch exists -- seems like a good candidate.
+        self.svn_branch = svn_refs.values()[0]
+      elif len(svn_refs) > 1:
+        # We have more than one remote branch available.  We don't
+        # want to go through all of history, so read a line from the
+        # pipe at a time.
+        # The -100 is an arbitrary limit so we don't search forever.
+        cmd = ['git', 'log', '-100', '--pretty=medium']
+        proc = Popen(cmd, stdout=subprocess.PIPE)
+        for line in proc.stdout:
+          match = git_svn_re.match(line)
+          if match:
+            url = match.group(1)
+            if url in svn_refs:
+              self.svn_branch = svn_refs[url]
+              proc.stdout.close()  # Cut pipe.
+              break
+
+      if not self.svn_branch:
+        DieWithError('Can\'t guess svn branch -- try specifying it on the '
+            'command line')
+
+    return self.svn_branch
+
+  def GetTreeStatusUrl(self, error_ok=False):
+    if not self.tree_status_url:
+      error_message = ('You must configure your tree status URL by running '
+                       '"git cl config".')
+      self.tree_status_url = self._GetConfig('rietveld.tree-status-url',
+                                             error_ok=error_ok,
+                                             error_message=error_message)
+    return self.tree_status_url
+
+  def GetViewVCUrl(self):
+    if not self.viewvc_url:
+      self.viewvc_url = self._GetConfig('rietveld.viewvc-url', error_ok=True)
+    return self.viewvc_url
+
+  def _GetConfig(self, param, **kwargs):
+    self.LazyUpdateIfNeeded()
+    return RunGit(['config', param], **kwargs).strip()
+
+
+settings = Settings()
+
+
+did_migrate_check = False
+def CheckForMigration():
+  """Migrate from the old issue format, if found.
+
+  We used to store the branch<->issue mapping in a file in .git, but it's
+  better to store it in the .git/config, since deleting a branch deletes that
+  branch's entry there.
+  """
+
+  # Don't run more than once.
+  global did_migrate_check
+  if did_migrate_check:
+    return
+
+  gitdir = RunGit(['rev-parse', '--git-dir']).strip()
+  storepath = os.path.join(gitdir, 'cl-mapping')
+  if os.path.exists(storepath):
+    print "old-style git-cl mapping file (%s) found; migrating." % storepath
+    store = open(storepath, 'r')
+    for line in store:
+      branch, issue = line.strip().split()
+      RunGit(['config', 'branch.%s.rietveldissue' % ShortBranchName(branch),
+              issue])
+    store.close()
+    os.remove(storepath)
+  did_migrate_check = True
+
+
+def ShortBranchName(branch):
+  """Convert a name like 'refs/heads/foo' to just 'foo'."""
+  return branch.replace('refs/heads/', '')
+
+
+class Changelist(object):
+  def __init__(self, branchref=None):
+    # Poke settings so we get the "configure your server" message if necessary.
+    settings.GetDefaultServerUrl()
+    self.branchref = branchref
+    if self.branchref:
+      self.branch = ShortBranchName(self.branchref)
+    else:
+      self.branch = None
+    self.rietveld_server = None
+    self.upstream_branch = None
+    self.has_issue = False
+    self.issue = None
+    self.has_description = False
+    self.description = None
+    self.has_patchset = False
+    self.patchset = None
+
+  def GetBranch(self):
+    """Returns the short branch name, e.g. 'master'."""
+    if not self.branch:
+      self.branchref = RunGit(['symbolic-ref', 'HEAD']).strip()
+      self.branch = ShortBranchName(self.branchref)
+    return self.branch
+
+  def GetBranchRef(self):
+    """Returns the full branch name, e.g. 'refs/heads/master'."""
+    self.GetBranch()  # Poke the lazy loader.
+    return self.branchref
+
+  def FetchUpstreamTuple(self):
+    """Returns a tuple containg remote and remote ref,
+       e.g. 'origin', 'refs/heads/master'
+    """
+    remote = '.'
+    branch = self.GetBranch()
+    upstream_branch = RunGit(['config', 'branch.%s.merge' % branch],
+                             error_ok=True).strip()
+    if upstream_branch:
+      remote = RunGit(['config', 'branch.%s.remote' % branch]).strip()
+    else:
+      # Fall back on trying a git-svn upstream branch.
+      if settings.GetIsGitSvn():
+        upstream_branch = settings.GetSVNBranch()
+      else:
+        # Else, try to guess the origin remote.
+        remote_branches = RunGit(['branch', '-r']).split()
+        if 'origin/master' in remote_branches:
+          # Fall back on origin/master if it exits.
+          remote = 'origin'
+          upstream_branch = 'refs/heads/master'
+        elif 'origin/trunk' in remote_branches:
+          # Fall back on origin/trunk if it exists. Generally a shared
+          # git-svn clone
+          remote = 'origin'
+          upstream_branch = 'refs/heads/trunk'
+        else:
+          DieWithError("""Unable to determine default branch to diff against.
+Either pass complete "git diff"-style arguments, like
+  git cl upload origin/master
+or verify this branch is set up to track another (via the --track argument to
+"git checkout -b ...").""")
+
+    return remote, upstream_branch
+
+  def GetUpstreamBranch(self):
+    if self.upstream_branch is None:
+      remote, upstream_branch = self.FetchUpstreamTuple()
+      if remote is not '.':
+        upstream_branch = upstream_branch.replace('heads', 'remotes/' + remote)
+      self.upstream_branch = upstream_branch
+    return self.upstream_branch
+
+  def GetRemoteUrl(self):
+    """Return the configured remote URL, e.g. 'git://example.org/foo.git/'.
+
+    Returns None if there is no remote.
+    """
+    remote = self.FetchUpstreamTuple()[0]
+    if remote == '.':
+      return None
+    return RunGit(['config', 'remote.%s.url' % remote], error_ok=True).strip()
+
+  def GetIssue(self):
+    if not self.has_issue:
+      CheckForMigration()
+      issue = RunGit(['config', self._IssueSetting()], error_ok=True).strip()
+      if issue:
+        self.issue = issue
+        self.rietveld_server = FixUrl(RunGit(
+            ['config', self._RietveldServer()], error_ok=True).strip())
+      else:
+        self.issue = None
+      if not self.rietveld_server:
+        self.rietveld_server = settings.GetDefaultServerUrl()
+      self.has_issue = True
+    return self.issue
+
+  def GetRietveldServer(self):
+    self.GetIssue()
+    return self.rietveld_server
+
+  def GetIssueURL(self):
+    """Get the URL for a particular issue."""
+    return '%s/%s' % (self.GetRietveldServer(), self.GetIssue())
+
+  def GetDescription(self, pretty=False):
+    if not self.has_description:
+      if self.GetIssue():
+        path = '/' + self.GetIssue() + '/description'
+        rpc_server = self._RpcServer()
+        self.description = rpc_server.Send(path).strip()
+      self.has_description = True
+    if pretty:
+      wrapper = textwrap.TextWrapper()
+      wrapper.initial_indent = wrapper.subsequent_indent = '  '
+      return wrapper.fill(self.description)
+    return self.description
+
+  def GetPatchset(self):
+    if not self.has_patchset:
+      patchset = RunGit(['config', self._PatchsetSetting()],
+                        error_ok=True).strip()
+      if patchset:
+        self.patchset = patchset
+      else:
+        self.patchset = None
+      self.has_patchset = True
+    return self.patchset
+
+  def SetPatchset(self, patchset):
+    """Set this branch's patchset.  If patchset=0, clears the patchset."""
+    if patchset:
+      RunGit(['config', self._PatchsetSetting(), str(patchset)])
+    else:
+      RunGit(['config', '--unset', self._PatchsetSetting()],
+             swallow_stderr=True, error_ok=True)
+    self.has_patchset = False
+
+  def SetIssue(self, issue):
+    """Set this branch's issue.  If issue=0, clears the issue."""
+    if issue:
+      RunGit(['config', self._IssueSetting(), str(issue)])
+      if self.rietveld_server:
+        RunGit(['config', self._RietveldServer(), self.rietveld_server])
+    else:
+      RunGit(['config', '--unset', self._IssueSetting()])
+      self.SetPatchset(0)
+    self.has_issue = False
+
+  def CloseIssue(self):
+    rpc_server = self._RpcServer()
+    # Newer versions of Rietveld require us to pass an XSRF token to POST, so
+    # we fetch it from the server.  (The version used by Chromium has been
+    # modified so the token isn't required when closing an issue.)
+    xsrf_token = rpc_server.Send('/xsrf_token',
+                                 extra_headers={'X-Requesting-XSRF-Token': '1'})
+
+    # You cannot close an issue with a GET.
+    # We pass an empty string for the data so it is a POST rather than a GET.
+    data = [("description", self.description),
+            ("xsrf_token", xsrf_token)]
+    ctype, body = upload.EncodeMultipartFormData(data, [])
+    rpc_server.Send('/' + self.GetIssue() + '/close', body, ctype)
+
+  def _RpcServer(self):
+    """Returns an upload.RpcServer() to access this review's rietveld instance.
+    """
+    server = self.GetRietveldServer()
+    return upload.GetRpcServer(server, save_cookies=True)
+
+  def _IssueSetting(self):
+    """Return the git setting that stores this change's issue."""
+    return 'branch.%s.rietveldissue' % self.GetBranch()
+
+  def _PatchsetSetting(self):
+    """Return the git setting that stores this change's most recent patchset."""
+    return 'branch.%s.rietveldpatchset' % self.GetBranch()
+
+  def _RietveldServer(self):
+    """Returns the git setting that stores this change's rietveld server."""
+    return 'branch.%s.rietveldserver' % self.GetBranch()
+
+
+def GetCodereviewSettingsInteractively():
+  """Prompt the user for settings."""
+  server = settings.GetDefaultServerUrl(error_ok=True)
+  prompt = 'Rietveld server (host[:port])'
+  prompt += ' [%s]' % (server or DEFAULT_SERVER)
+  newserver = raw_input(prompt + ': ')
+  if not server and not newserver:
+    newserver = DEFAULT_SERVER
+  if newserver and newserver != server:
+    RunGit(['config', 'rietveld.server', newserver])
+
+  def SetProperty(initial, caption, name):
+    prompt = caption
+    if initial:
+      prompt += ' ("x" to clear) [%s]' % initial
+    new_val = raw_input(prompt + ': ')
+    if new_val == 'x':
+      RunGit(['config', '--unset-all', 'rietveld.' + name], error_ok=True)
+    elif new_val and new_val != initial:
+      RunGit(['config', 'rietveld.' + name, new_val])
+
+  SetProperty(settings.GetCCList(), 'CC list', 'cc')
+  SetProperty(settings.GetTreeStatusUrl(error_ok=True), 'Tree status URL',
+              'tree-status-url')
+  SetProperty(settings.GetViewVCUrl(), 'ViewVC URL', 'viewvc-url')
+
+  # TODO: configure a default branch to diff against, rather than this
+  # svn-based hackery.
+
+
+def FindCodereviewSettingsFile(filename='codereview.settings'):
+  """Finds the given file starting in the cwd and going up.
+
+  Only looks up to the top of the repository unless an
+  'inherit-review-settings-ok' file exists in the root of the repository.
+  """
+  inherit_ok_file = 'inherit-review-settings-ok'
+  cwd = os.getcwd()
+  root = os.path.abspath(RunGit(['rev-parse', '--show-cdup']).strip())
+  if os.path.isfile(os.path.join(root, inherit_ok_file)):
+    root = '/'
+  while True:
+    if filename in os.listdir(cwd):
+      if os.path.isfile(os.path.join(cwd, filename)):
+        return open(os.path.join(cwd, filename))
+    if cwd == root:
+      break
+    cwd = os.path.dirname(cwd)
+
+
+def LoadCodereviewSettingsFromFile(fileobj):
+  """Parse a codereview.settings file and updates hooks."""
+  def DownloadToFile(url, filename):
+    filename = os.path.join(settings.GetRoot(), filename)
+    contents = urllib2.urlopen(url).read()
+    fileobj = open(filename, 'w')
+    fileobj.write(contents)
+    fileobj.close()
+    os.chmod(filename, 0755)
+    return 0
+
+  keyvals = {}
+  for line in fileobj.read().splitlines():
+    if not line or line.startswith("#"):
+      continue
+    k, v = line.split(": ", 1)
+    keyvals[k] = v
+
+  def GetProperty(name):
+    return keyvals.get(name)
+
+  def SetProperty(name, setting, unset_error_ok=False):
+    fullname = 'rietveld.' + name
+    if setting in keyvals:
+      RunGit(['config', fullname, keyvals[setting]])
+    else:
+      RunGit(['config', '--unset-all', fullname], error_ok=unset_error_ok)
+
+  SetProperty('server', 'CODE_REVIEW_SERVER')
+  # Only server setting is required. Other settings can be absent.
+  # In that case, we ignore errors raised during option deletion attempt.
+  SetProperty('cc', 'CC_LIST', unset_error_ok=True)
+  SetProperty('tree-status-url', 'STATUS', unset_error_ok=True)
+  SetProperty('viewvc-url', 'VIEW_VC', unset_error_ok=True)
+
+  if 'PUSH_URL_CONFIG' in keyvals and 'ORIGIN_URL_CONFIG' in keyvals:
+    #should be of the form
+    #PUSH_URL_CONFIG: url.ssh://gitrw.chromium.org.pushinsteadof
+    #ORIGIN_URL_CONFIG: http://src.chromium.org/git
+    RunGit(['config', keyvals['PUSH_URL_CONFIG'],
+            keyvals['ORIGIN_URL_CONFIG']])
+
+  # Update the hooks if the local hook files aren't present already.
+  if GetProperty('GITCL_PREUPLOAD') and not os.path.isfile(PREUPLOAD_HOOK):
+    DownloadToFile(GetProperty('GITCL_PREUPLOAD'), PREUPLOAD_HOOK)
+  if GetProperty('GITCL_PREDCOMMIT') and not os.path.isfile(PREDCOMMIT_HOOK):
+    DownloadToFile(GetProperty('GITCL_PREDCOMMIT'), PREDCOMMIT_HOOK)
+  return 0
+
+
+@usage('[repo root containing codereview.settings]')
+def CMDconfig(parser, args):
+  """edit configuration for this tree"""
+
+  (options, args) = parser.parse_args(args)
+  if len(args) == 0:
+    GetCodereviewSettingsInteractively()
+    return 0
+
+  url = args[0]
+  if not url.endswith('codereview.settings'):
+    url = os.path.join(url, 'codereview.settings')
+
+  # Load code review settings and download hooks (if available).
+  LoadCodereviewSettingsFromFile(urllib2.urlopen(url))
+  return 0
+
+
+def CMDstatus(parser, args):
+  """show status of changelists"""
+  parser.add_option('--field',
+                    help='print only specific field (desc|id|patch|url)')
+  (options, args) = parser.parse_args(args)
+
+  # TODO: maybe make show_branches a flag if necessary.
+  show_branches = not options.field
+
+  if show_branches:
+    branches = RunGit(['for-each-ref', '--format=%(refname)', 'refs/heads'])
+    if branches:
+      print 'Branches associated with reviews:'
+      for branch in sorted(branches.splitlines()):
+        cl = Changelist(branchref=branch)
+        print "  %10s: %s" % (cl.GetBranch(), cl.GetIssue())
+
+  cl = Changelist()
+  if options.field:
+    if options.field.startswith('desc'):
+      print cl.GetDescription()
+    elif options.field == 'id':
+      issueid = cl.GetIssue()
+      if issueid:
+        print issueid
+    elif options.field == 'patch':
+      patchset = cl.GetPatchset()
+      if patchset:
+        print patchset
+    elif options.field == 'url':
+      url = cl.GetIssueURL()
+      if url:
+        print url
+  else:
+    print
+    print 'Current branch:',
+    if not cl.GetIssue():
+      print 'no issue assigned.'
+      return 0
+    print cl.GetBranch()
+    print 'Issue number:', cl.GetIssue(), '(%s)' % cl.GetIssueURL()
+    print 'Issue description:'
+    print cl.GetDescription(pretty=True)
+  return 0
+
+
+@usage('[issue_number]')
+def CMDissue(parser, args):
+  """Set or display the current code review issue number.
+
+  Pass issue number 0 to clear the current issue.
+"""
+  (options, args) = parser.parse_args(args)
+
+  cl = Changelist()
+  if len(args) > 0:
+    try:
+      issue = int(args[0])
+    except ValueError:
+      DieWithError('Pass a number to set the issue or none to list it.\n'
+          'Maybe you want to run git cl status?')
+    cl.SetIssue(issue)
+  print 'Issue number:', cl.GetIssue(), '(%s)' % cl.GetIssueURL()
+  return 0
+
+
+def CreateDescriptionFromLog(args):
+  """Pulls out the commit log to use as a base for the CL description."""
+  log_args = []
+  if len(args) == 1 and not args[0].endswith('.'):
+    log_args = [args[0] + '..']
+  elif len(args) == 1 and args[0].endswith('...'):
+    log_args = [args[0][:-1]]
+  elif len(args) == 2:
+    log_args = [args[0] + '..' + args[1]]
+  else:
+    log_args = args[:]  # Hope for the best!
+  return RunGit(['log', '--pretty=format:%s\n\n%b'] + log_args)
+
+
+def UserEditedLog(starting_text):
+  """Given some starting text, let the user edit it and return the result."""
+  editor = os.getenv('EDITOR', 'vi')
+
+  (file_handle, filename) = tempfile.mkstemp()
+  fileobj = os.fdopen(file_handle, 'w')
+  fileobj.write(starting_text)
+  fileobj.close()
+
+  ret = subprocess.call(editor + ' ' + filename, shell=True)
+  if ret != 0:
+    os.remove(filename)
+    return
+
+  fileobj = open(filename)
+  text = fileobj.read()
+  fileobj.close()
+  os.remove(filename)
+  stripcomment_re = re.compile(r'^#.*$', re.MULTILINE)
+  return stripcomment_re.sub('', text).strip()
+
+
+def RunHook(hook, upstream_branch, error_ok=False):
+  """Run a given hook if it exists. By default, we fail on errors."""
+  hook = '%s/%s' % (settings.GetRoot(), hook)
+  if not os.path.exists(hook):
+    return
+  return RunCommand([hook, upstream_branch], error_ok=error_ok,
+                    redirect_stdout=False)
+
+
+def CMDpresubmit(parser, args):
+  """run presubmit tests on the current changelist"""
+  parser.add_option('--upload', action='store_true',
+                    help='Run upload hook instead of the push/dcommit hook')
+  (options, args) = parser.parse_args(args)
+
+  # Make sure index is up-to-date before running diff-index.
+  RunGit(['update-index', '--refresh', '-q'], error_ok=True)
+  if RunGit(['diff-index', 'HEAD']):
+    # TODO(maruel): Is this really necessary?
+    print 'Cannot presubmit with a dirty tree.  You must commit locally first.'
+    return 1
+
+  if args:
+    base_branch = args[0]
+  else:
+    # Default to diffing against the "upstream" branch.
+    base_branch = Changelist().GetUpstreamBranch()
+
+  if options.upload:
+    print '*** Presubmit checks for UPLOAD would report: ***'
+    return not RunHook(PREUPLOAD_HOOK, upstream_branch=base_branch,
+        error_ok=True)
+  else:
+    print '*** Presubmit checks for DCOMMIT would report: ***'
+    return not RunHook(PREDCOMMIT_HOOK, upstream_branch=base_branch,
+        error_ok=True)
+
+
+@usage('[args to "git diff"]')
+def CMDupload(parser, args):
+  """upload the current changelist to codereview"""
+  parser.add_option('--bypass-hooks', action='store_true', dest='bypass_hooks',
+                    help='bypass upload presubmit hook')
+  parser.add_option('-m', dest='message', help='message for patch')
+  parser.add_option('-r', '--reviewers',
+                    help='reviewer email addresses')
+  parser.add_option('--send-mail', action='store_true',
+                    help='send email to reviewer immediately')
+  parser.add_option("--emulate_svn_auto_props", action="store_true",
+                    dest="emulate_svn_auto_props",
+                    help="Emulate Subversion's auto properties feature.")
+  parser.add_option("--desc_from_logs", action="store_true",
+                    dest="from_logs",
+                    help="""Squashes git commit logs into change description and
+                            uses message as subject""")
+  (options, args) = parser.parse_args(args)
+
+  # Make sure index is up-to-date before running diff-index.
+  RunGit(['update-index', '--refresh', '-q'], error_ok=True)
+  if RunGit(['diff-index', 'HEAD']):
+    print 'Cannot upload with a dirty tree.  You must commit locally first.'
+    return 1
+
+  cl = Changelist()
+  if args:
+    base_branch = args[0]
+  else:
+    # Default to diffing against the "upstream" branch.
+    base_branch = cl.GetUpstreamBranch()
+    args = [base_branch + "..."]
+
+  if not options.bypass_hooks:
+    RunHook(PREUPLOAD_HOOK, upstream_branch=base_branch, error_ok=False)
+
+  # --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']
+  subprocess.call(['git', 'diff', '--no-ext-diff', '--stat', '-M'] + args,
+                  env=env)
+
+  upload_args = ['--assume_yes']  # Don't ask about untracked files.
+  upload_args.extend(['--server', cl.GetRietveldServer()])
+  if options.reviewers:
+    upload_args.extend(['--reviewers', options.reviewers])
+  upload_args.extend(['--cc', settings.GetCCList()])
+  if options.emulate_svn_auto_props:
+    upload_args.append('--emulate_svn_auto_props')
+  if options.send_mail:
+    if not options.reviewers:
+      DieWithError("Must specify reviewers to send email.")
+    upload_args.append('--send_mail')
+  if options.from_logs and not options.message:
+    print 'Must set message for subject line if using desc_from_logs'
+    return 1
+
+  change_desc = None
+
+  if cl.GetIssue():
+    if options.message:
+      upload_args.extend(['--message', options.message])
+    upload_args.extend(['--issue', cl.GetIssue()])
+    print ("This branch is associated with issue %s. "
+           "Adding patch to that issue." % cl.GetIssue())
+  else:
+    log_desc = CreateDescriptionFromLog(args)
+    if options.from_logs:
+      # Uses logs as description and message as subject.
+      subject = options.message
+      change_desc = subject + '\n\n' + log_desc
+    else:
+      initial_text = """# Enter a description of the change.
+# This will displayed on the codereview site.
+# The first line will also be used as the subject of the review.
+"""
+      if 'BUG=' not in log_desc:
+        log_desc += '\nBUG='
+      if 'TEST=' not in log_desc:
+        log_desc += '\nTEST='
+      change_desc = UserEditedLog(initial_text + log_desc)
+      subject = ''
+      if change_desc:
+        subject = change_desc.splitlines()[0]
+    if not change_desc:
+      print "Description is empty; aborting."
+      return 1
+    upload_args.extend(['--message', subject])
+    upload_args.extend(['--description', change_desc])
+
+  # Include the upstream repo's URL in the change -- this is useful for
+  # projects that have their source spread across multiple repos.
+  remote_url = None
+  if settings.GetIsGitSvn():
+    data = RunGit(['svn', 'info'])
+    if data:
+      keys = dict(line.split(': ', 1) for line in data.splitlines()
+                  if ': ' in line)
+      remote_url = keys.get('URL', None)
+  else:
+    if cl.GetRemoteUrl() and '/' in cl.GetUpstreamBranch():
+      remote_url = (cl.GetRemoteUrl() + '@'
+                    + cl.GetUpstreamBranch().split('/')[-1])
+  if remote_url:
+    upload_args.extend(['--base_url', remote_url])
+
+  try:
+    issue, patchset = upload.RealMain(['upload'] + upload_args + args)
+  except:
+    # If we got an exception after the user typed a description for their
+    # change, back up the description before re-raising.
+    if change_desc:
+      backup_path = os.path.expanduser(DESCRIPTION_BACKUP_FILE)
+      print '\nGot exception while uploading -- saving description to %s\n' \
+          % backup_path
+      backup_file = open(backup_path, 'w')
+      backup_file.write(change_desc)
+      backup_file.close()
+    raise
+
+  if not cl.GetIssue():
+    cl.SetIssue(issue)
+  cl.SetPatchset(patchset)
+  return 0
+
+
+def SendUpstream(parser, args, cmd):
+  """Common code for CmdPush and CmdDCommit
+
+  Squashed commit into a single.
+  Updates changelog with metadata (e.g. pointer to review).
+  Pushes/dcommits the code upstream.
+  Updates review and closes.
+  """
+  parser.add_option('--bypass-hooks', action='store_true', dest='bypass_hooks',
+                    help='bypass upload presubmit hook')
+  parser.add_option('-m', dest='message',
+                    help="override review description")
+  parser.add_option('-f', action='store_true', dest='force',
+                    help="force yes to questions (don't prompt)")
+  parser.add_option('-c', dest='contributor',
+                    help="external contributor for patch (appended to " +
+                         "description and used as author for git). Should be " +
+                         "formatted as 'First Last <email@example.com>'")
+  parser.add_option('--tbr', action='store_true', dest='tbr',
+                    help="short for 'to be reviewed', commit branch " +
+                         "even without uploading for review")
+  (options, args) = parser.parse_args(args)
+  cl = Changelist()
+
+  if not args or cmd == 'push':
+    # Default to merging against our best guess of the upstream branch.
+    args = [cl.GetUpstreamBranch()]
+
+  base_branch = args[0]
+
+  if RunGit(['diff-index', 'HEAD']):
+    print 'Cannot %s with a dirty tree.  You must commit locally first.' % cmd
+    return 1
+
+  # This rev-list syntax means "show all commits not in my branch that
+  # are in base_branch".
+  upstream_commits = RunGit(['rev-list', '^' + cl.GetBranchRef(),
+                             base_branch]).splitlines()
+  if upstream_commits:
+    print ('Base branch "%s" has %d commits '
+           'not in this branch.' % (base_branch, len(upstream_commits)))
+    print 'Run "git merge %s" before attempting to %s.' % (base_branch, cmd)
+    return 1
+
+  if cmd == 'dcommit':
+    # This is the revision `svn dcommit` will commit on top of.
+    svn_head = RunGit(['log', '--grep=^git-svn-id:', '-1',
+                       '--pretty=format:%H'])
+    extra_commits = RunGit(['rev-list', '^' + svn_head, base_branch])
+    if extra_commits:
+      print ('This branch has %d additional commits not upstreamed yet.'
+             % len(extra_commits.splitlines()))
+      print ('Upstream "%s" or rebase this branch on top of the upstream trunk '
+             'before attempting to %s.' % (base_branch, cmd))
+      return 1
+
+  if not options.force and not options.bypass_hooks:
+    RunHook(PREDCOMMIT_HOOK, upstream_branch=base_branch, error_ok=False)
+
+    if cmd == 'dcommit':
+      # Check the tree status if the tree status URL is set.
+      status = GetTreeStatus()
+      if 'closed' == status:
+        print ('The tree is closed.  Please wait for it to reopen. Use '
+               '"git cl dcommit -f" to commit on a closed tree.')
+        return 1
+      elif 'unknown' == status:
+        print ('Unable to determine tree status.  Please verify manually and '
+               'use "git cl dcommit -f" to commit on a closed tree.')
+
+  description = options.message
+  if not options.tbr:
+    # It is important to have these checks early.  Not only for user
+    # convenience, but also because the cl object then caches the correct values
+    # of these fields even as we're juggling branches for setting up the commit.
+    if not cl.GetIssue():
+      print 'Current issue unknown -- has this branch been uploaded?'
+      print 'Use --tbr to commit without review.'
+      return 1
+
+    if not description:
+      description = cl.GetDescription()
+
+    if not description:
+      print 'No description set.'
+      print 'Visit %s/edit to set it.' % (cl.GetIssueURL())
+      return 1
+
+    description += "\n\nReview URL: %s" % cl.GetIssueURL()
+  else:
+    if not description:
+      # Submitting TBR.  See if there's already a description in Rietveld, else
+      # create a template description. Eitherway, give the user a chance to edit
+      # it to fill in the TBR= field.
+      if cl.GetIssue():
+        description = cl.GetDescription()
+
+      if not description:
+        description = """# Enter a description of the change.
+# This will be used as the change log for the commit.
+
+"""
+        description += CreateDescriptionFromLog(args)
+
+      description = UserEditedLog(description + '\nTBR=')
+
+    if not description:
+      print "Description empty; aborting."
+      return 1
+
+  if options.contributor:
+    if not re.match('^.*\s<\S+@\S+>$', options.contributor):
+      print "Please provide contibutor as 'First Last <email@example.com>'"
+      return 1
+    description += "\nPatch from %s." % options.contributor
+  print 'Description:', repr(description)
+
+  branches = [base_branch, cl.GetBranchRef()]
+  if not options.force:
+    subprocess.call(['git', 'diff', '--stat'] + branches)
+    raw_input("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 "merge --squash" into a new commit branch, then
+  # dcommitting that.
+  MERGE_BRANCH = 'git-cl-commit'
+  # Delete the merge branch if it already exists.
+  if RunGitWithCode(['show-ref', '--quiet', '--verify',
+                     'refs/heads/' + MERGE_BRANCH])[0] == 0:
+    RunGit(['branch', '-D', MERGE_BRANCH])
+
+  # We might be in a directory that's present in this branch but not in the
+  # trunk.  Move up to the top of the tree so that git commands that expect a
+  # valid CWD won't fail after we check out the merge branch.
+  rel_base_path = RunGit(['rev-parse', '--show-cdup']).strip()
+  if rel_base_path:
+    os.chdir(rel_base_path)
+
+  # Stuff our change into the merge branch.
+  # We wrap in a try...finally block so if anything goes wrong,
+  # we clean up the branches.
+  try:
+    RunGit(['checkout', '-q', '-b', MERGE_BRANCH, base_branch])
+    RunGit(['merge', '--squash', cl.GetBranchRef()])
+    if options.contributor:
+      RunGit(['commit', '--author', options.contributor, '-m', description])
+    else:
+      RunGit(['commit', '-m', description])
+    if cmd == 'push':
+      # push the merge branch.
+      remote, branch = cl.FetchUpstreamTuple()
+      retcode, output = RunGitWithCode(
+          ['push', '--porcelain', remote, 'HEAD:%s' % branch])
+      logging.debug(output)
+    else:
+      # dcommit the merge branch.
+      output = RunGit(['svn', 'dcommit', '--no-rebase'])
+  finally:
+    # And then swap back to the original branch and clean up.
+    RunGit(['checkout', '-q', cl.GetBranch()])
+    RunGit(['branch', '-D', MERGE_BRANCH])
+
+  if cl.GetIssue():
+    if cmd == 'dcommit' and 'Committed r' in output:
+      revision = re.match('.*?\nCommitted r(\\d+)', output, re.DOTALL).group(1)
+    elif cmd == 'push' and retcode == 0:
+      revision = output.splitlines()[1].split('\t')[2].split('..')[1]
+    else:
+      return 1
+    viewvc_url = settings.GetViewVCUrl()
+    if viewvc_url and revision:
+      cl.description += ('\n\nCommitted: ' + viewvc_url + revision)
+    print ('Closing issue '
+           '(you may be prompted for your codereview password)...')
+    cl.CloseIssue()
+    cl.SetIssue(0)
+  return 0
+
+
+@usage('[upstream branch to apply against]')
+def CMDdcommit(parser, args):
+  """commit the current changelist via git-svn"""
+  if not settings.GetIsGitSvn():
+    print('This doesn\'t appear to be an SVN repository.')
+    print('Are you sure you didn\'t mean \'git cl push\'?')
+    raw_input('[Press enter to dcommit or ctrl-C to quit]')
+  return SendUpstream(parser, args, 'dcommit')
+
+
+@usage('[upstream branch to apply against]')
+def CMDpush(parser, args):
+  """commit the current changelist via git"""
+  if settings.GetIsGitSvn():
+    print('This appears to be an SVN repository.')
+    print('Are you sure you didn\'t mean \'git cl dcommit\'?')
+    raw_input('[Press enter to push or ctrl-C to quit]')
+  return SendUpstream(parser, args, 'push')
+
+
+@usage('<patch url or issue id>')
+def CMDpatch(parser, args):
+  """patch in a code review"""
+  parser.add_option('-b', dest='newbranch',
+                    help='create a new branch off trunk for the patch')
+  parser.add_option('-f', action='store_true', dest='force',
+                    help='with -b, clobber any existing branch')
+  parser.add_option('--reject', action='store_true', dest='reject',
+                    help='allow failed patches and spew .rej files')
+  parser.add_option('-n', '--no-commit', action='store_true', dest='nocommit',
+                    help="don't commit after patch applies")
+  (options, args) = parser.parse_args(args)
+  if len(args) != 1:
+    parser.print_help()
+    return 1
+  input = args[0]
+
+  if re.match(r'\d+', input):
+    # Input is an issue id.  Figure out the URL.
+    issue = input
+    server = settings.GetDefaultServerUrl()
+    fetch = urllib2.urlopen('%s/%s' % (server, issue)).read()
+    m = re.search(r'/download/issue[0-9]+_[0-9]+.diff', fetch)
+    if not m:
+      DieWithError('Must pass an issue ID or full URL for '
+          '\'Download raw patch set\'')
+    url = '%s%s' % (server, m.group(0).strip())
+  else:
+    # Assume it's a URL to the patch. Default to http.
+    input = FixUrl(input)
+    match = re.match(r'.*?/issue(\d+)_\d+.diff', input)
+    if match:
+      issue = match.group(1)
+      url = input
+    else:
+      DieWithError('Must pass an issue ID or full URL for '
+          '\'Download raw patch set\'')
+
+  if options.newbranch:
+    if options.force:
+      RunGit(['branch', '-D', options.newbranch],
+         swallow_stderr=True, error_ok=True)
+    RunGit(['checkout', '-b', options.newbranch,
+            Changelist().GetUpstreamBranch()])
+
+  # Switch up to the top-level directory, if necessary, in preparation for
+  # applying the patch.
+  top = RunGit(['rev-parse', '--show-cdup']).strip()
+  if top:
+    os.chdir(top)
+
+  patch_data = urllib2.urlopen(url).read()
+  # Git patches have a/ at the beginning of source paths.  We strip that out
+  # with a sed script rather than the -p flag to patch so we can feed either
+  # Git or svn-style patches into the same apply command.
+  # re.sub() should be used but flags=re.MULTILINE is only in python 2.7.
+  sed_proc = Popen(['sed', '-e', 's|^--- a/|--- |; s|^+++ b/|+++ |'],
+      stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+  patch_data = sed_proc.communicate(patch_data)[0]
+  if sed_proc.returncode:
+    DieWithError('Git patch mungling failed.')
+  logging.info(patch_data)
+  # We use "git apply" to apply the patch instead of "patch" so that we can
+  # pick up file adds.
+  # The --index flag means: also insert into the index (so we catch adds).
+  cmd = ['git', 'apply', '--index', '-p0']
+  if options.reject:
+    cmd.append('--reject')
+  patch_proc = Popen(cmd, stdin=subprocess.PIPE)
+  patch_proc.communicate(patch_data)
+  if patch_proc.returncode:
+    DieWithError('Failed to apply the patch')
+
+  # If we had an issue, commit the current state and register the issue.
+  if not options.nocommit:
+    RunGit(['commit', '-m', 'patch from issue %s' % issue])
+    cl = Changelist()
+    cl.SetIssue(issue)
+    print "Committed patch."
+  else:
+    print "Patch applied to index."
+  return 0
+
+
+def CMDrebase(parser, args):
+  """rebase current branch on top of svn repo"""
+  # Provide a wrapper for git svn rebase to help avoid accidental
+  # git svn dcommit.
+  # It's the only command that doesn't use parser at all since we just defer
+  # execution to git-svn.
+  RunGit(['svn', 'rebase'] + args, redirect_stdout=False)
+  return 0
+
+
+def GetTreeStatus():
+  """Fetches the tree status and returns either 'open', 'closed',
+  'unknown' or 'unset'."""
+  url = settings.GetTreeStatusUrl(error_ok=True)
+  if url:
+    status = urllib2.urlopen(url).read().lower()
+    if status.find('closed') != -1 or status == '0':
+      return 'closed'
+    elif status.find('open') != -1 or status == '1':
+      return 'open'
+    return 'unknown'
+
+  return 'unset'
+
+def GetTreeStatusReason():
+  """Fetches the tree status from a json url and returns the message
+  with the reason for the tree to be opened or closed."""
+  # Don't import it at file level since simplejson is not installed by default
+  # on python 2.5 and it is only used for git-cl tree which isn't often used,
+  # forcing everyone to install simplejson isn't efficient.
+  try:
+    import simplejson as json
+  except ImportError:
+    try:
+      import json
+      # Some versions of python2.5 have an incomplete json module. Check to make
+      # sure loads exists.
+      json.loads
+    except (ImportError, AttributeError):
+      print >> sys.stderr, 'Please install simplejson'
+      sys.exit(1)
+
+  json_url = 'http://chromium-status.appspot.com/current?format=json'
+  connection = urllib2.urlopen(json_url)
+  status = json.loads(connection.read())
+  connection.close()
+  return status['message']
+
+def CMDtree(parser, args):
+  """show the status of the tree"""
+  (options, args) = parser.parse_args(args)
+  status = GetTreeStatus()
+  if 'unset' == status:
+    print 'You must configure your tree status URL by running "git cl config".'
+    return 2
+
+  print "The tree is %s" % status
+  print
+  print GetTreeStatusReason()
+  if status != 'open':
+    return 1
+  return 0
+
+
+def CMDupstream(parser, args):
+  """print the name of the upstream branch, if any"""
+  (options, args) = parser.parse_args(args)
+  cl = Changelist()
+  print cl.GetUpstreamBranch()
+  return 0
+
+
+def Command(name):
+  return getattr(sys.modules[__name__], 'CMD' + name, None)
+
+
+def CMDhelp(parser, args):
+  """print list of commands or help for a specific command"""
+  (options, args) = parser.parse_args(args)
+  if len(args) == 1:
+    return main(args + ['--help'])
+  parser.print_help()
+  return 0
+
+
+def GenUsage(parser, command):
+  """Modify an OptParse object with the function's documentation."""
+  obj = Command(command)
+  more = getattr(obj, 'usage_more', '')
+  if command == 'help':
+    command = '<command>'
+  else:
+    # OptParser.description prefer nicely non-formatted strings.
+    parser.description = re.sub('[\r\n ]{2,}', ' ', obj.__doc__)
+  parser.set_usage('usage: %%prog %s [options] %s' % (command, more))
+
+
+def main(argv):
+  """Doesn't parse the arguments here, just find the right subcommand to
+  execute."""
+  # Do it late so all commands are listed.
+  CMDhelp.usage_more = ('\n\nCommands are:\n' + '\n'.join([
+      '  %-10s %s' % (fn[3:], Command(fn[3:]).__doc__.split('\n')[0].strip())
+      for fn in dir(sys.modules[__name__]) if fn.startswith('CMD')]))
+
+  # Create the option parse and add --verbose support.
+  parser = optparse.OptionParser()
+  parser.add_option('-v', '--verbose', action='store_true')
+  old_parser_args = parser.parse_args
+  def Parse(args):
+    options, args = old_parser_args(args)
+    if options.verbose:
+      logging.basicConfig(level=logging.DEBUG)
+    else:
+      logging.basicConfig(level=logging.WARNING)
+    return options, args
+  parser.parse_args = Parse
+
+  if argv:
+    command = Command(argv[0])
+    if command:
+      # "fix" the usage and the description now that we know the subcommand.
+      GenUsage(parser, argv[0])
+      try:
+        return command(parser, argv[1:])
+      except urllib2.HTTPError, e:
+        if e.code != 500:
+          raise
+        DieWithError(
+            ('AppEngine is misbehaving and returned HTTP %d, again. Keep faith '
+             '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__':
+  sys.exit(main(sys.argv[1:]))