Define -T/--no-topic to disable review submit with topic

The option -T/--no-topic disables review with topic (mutually
exclusive with -t/--topic).

It allows to submit:

* a change without your current branch name as topic,
* a change update without updating current topic.

Change-Id: I06309b14246cb455d55c6833ab6adb932995edfa

README.rst

@@ -41,6 +41,10 @@ If you want to supply a review topic::
 
     git review -t topic/awesome-feature
 
+If you want to disable autogenerated topic::
+
+    git review -T
+
 If you want to submit a branch for review and then remove the local branch::
 
     git review -f

git-review.1

@@ -38,7 +38,7 @@
 .Fl s
 .Op Ar branch
 .Nm
-.Op Fl fnuvDR
+.Op Fl fnuvDRT
 .Op Fl r Ar remote
 .Op Fl t Ar topic
 .Op Ar branch
@@ -138,6 +138,8 @@ Just run the repo setup commands but don\(aqt submit anything.
 .It Fl t Ar topic , Fl \-topic= Ns Ar topic
 Sets the target topic for this change on the gerrit server.
 If not specified, a bug number from the commit summary will be used. Alternatively, the local branch name will be used if different from remote branch.
+.It Fl T , Fl \-no\-topic
+Submit review without topic.
 .It Fl u , Fl \-update
 Skip cached local copies and force updates from network resources.
 .It Fl l , Fl \-list

git_review/cmd.py

@@ -1058,8 +1058,13 @@ def main():
 
     parser = argparse.ArgumentParser(usage=usage, description=COPYRIGHT)
 
-    parser.add_argument("-t", "--topic", dest="topic",
-                        help="Topic to submit branch to")
+    topic_arg_group = parser.add_mutually_exclusive_group()
+    topic_arg_group.add_argument("-t", "--topic", dest="topic",
+                                 help="Topic to submit branch to")
+    topic_arg_group.add_argument("-T", "--no-topic", dest="notopic",
+                                 action="store_true",
+                                 help="No topic except if explicitly provided")
+
     parser.add_argument("-D", "--draft", dest="draft", action="store_true",
                         help="Submit review as a draft")
     parser.add_argument("-c", "--compatible", dest="compatible",
@@ -1233,8 +1238,11 @@ def main():
         ref = "for"
 
     cmd = "git push %s HEAD:refs/%s/%s" % (remote, ref, branch)
-    topic = options.topic or get_topic(branch)
-    if topic != branch:
+    if options.topic is not None:
+        topic = options.topic
+    else:
+        topic = None if options.notopic else get_topic(branch)
+    if topic and topic != branch:
         cmd += "/%s" % topic
     if options.regenerate:
         print("Amending the commit to regenerate the change id\n")

git_review/tests/test_git_review.py

@@ -186,8 +186,9 @@ class GitReviewTestCase(tests.BaseGitReviewTestCase):
         self.assertIn('rebase', review_res)
         self.assertEqual(self._run_git('rev-parse', 'HEAD^1'), head)
 
-    def _assert_branch_would_be(self, branch):
-        output = self._run_git_review('-n')
+    def _assert_branch_would_be(self, branch, extra_args=None):
+        extra_args = extra_args or []
+        output = self._run_git_review('-n', *extra_args)
         # last non-empty line should be:
         #       git push gerrit HEAD:refs/publish/master
         last_line = output.strip().split('\n')[-1]
@@ -210,6 +211,11 @@ class GitReviewTestCase(tests.BaseGitReviewTestCase):
         finally:
             os.environ.update(LANG=lang_env)
 
+    def test_git_review_t(self):
+        self._run_git_review('-s')
+        self._simple_change('test file modified', 'commit message for bug 654')
+        self._assert_branch_would_be('master/zat', extra_args=['-t', 'zat'])
+
     def test_bug_topic(self):
         self._run_git_review('-s')
         self._simple_change('a change', 'new change for bug 123')
@@ -230,6 +236,15 @@ class GitReviewTestCase(tests.BaseGitReviewTestCase):
         self._simple_change('a change', 'new change not for bluepring\nasdf')
         self._assert_branch_would_be('master')
 
+    def test_git_review_T(self):
+        self._run_git_review('-s')
+        self._simple_change('test file modified', 'commit message for bug 456')
+        self._assert_branch_would_be('master/bug/456')
+        self._assert_branch_would_be('master', extra_args=['-T'])
+
+    def test_git_review_T_t(self):
+        self.assertRaises(Exception, self._run_git_review, '-T', '-t', 'taz')
+
     def test_git_review_l(self):
         self._run_git_review('-s')