Make `git cl description` work for Gerrit

This works in that it actually changes the description, but after
multiple changes, there's multiple footers added. I'm not sure if they
should be stripped in setting the description? Or is the problem in
FetchDescription() where it shouldn't be returning
'commit_with_footers', but rather something else?

Example change at https://chromium-review.googlesource.com/c/340430/.

R=tandrii@chromium.org
BUG=603207

Review URL: https://codereview.chromium.org/1917473002 .

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@300169 0039d316-1c4b-4281-b951-d872f2087c98

gerrit_util.py

@@ -541,6 +541,38 @@ def SubmitChange(host, change, wait_for_merge=True):
   return ReadHttpJsonResponse(conn, ignore_404=False)
 
 
+def SetCommitMessage(host, change, description):
+  """Updates a commit message."""
+  # First, edit the commit message in a draft.
+  path = 'changes/%s/edit:message' % change
+  body = {'message': description}
+  conn = CreateHttpConn(host, path, reqtype='PUT', body=body)
+  try:
+    ReadHttpResponse(conn, ignore_404=False)
+  except GerritError as e:
+    # On success, gerrit returns status 204; anything else is an error.
+    if e.http_status != 204:
+      raise
+  else:
+    raise GerritError(
+        'Unexpectedly received a 200 http status while editing message in '
+        'change %s' % change)
+
+  # And then publish it.
+  path = 'changes/%s/edit:publish' % change
+  conn = CreateHttpConn(host, path, reqtype='POST', body={})
+  try:
+    ReadHttpResponse(conn, ignore_404=False)
+  except GerritError as e:
+    # On success, gerrit returns status 204; anything else is an error.
+    if e.http_status != 204:
+      raise
+  else:
+    raise GerritError(
+        'Unexpectedly received a 200 http status while publishing message '
+        'change in %s' % change)
+
+
 def GetReviewers(host, change):
   """Get information about all reviewers attached to a change."""
   path = 'changes/%s/reviewers' % change

git_cl.py

@@ -2169,8 +2169,8 @@ class _GerritChangelistImpl(_ChangelistCodereviewBase):
     return gerrit_util.GetChangeDescriptionFromGitiles(url, current_rev)
 
   def UpdateDescriptionRemote(self, description):
-    # TODO(tandrii)
-    raise NotImplementedError()
+    gerrit_util.SetCommitMessage(self._GetGerritHost(), self.GetIssue(),
+                                 description)
 
   def CloseIssue(self):
     gerrit_util.AbandonChange(self._GetGerritHost(), self.GetIssue(), msg='')