Don't set topic when submitting no-topic patches

Change-Id: I8f8880791ad7e46fb9e18623ab8bd295457424b2
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

git_review/cmd.py

@@ -943,6 +943,10 @@ def get_topic(target_branch):
 
     branch_parts = branch_name.split("/")
     if len(branch_parts) >= 3 and branch_parts[0] == "review":
+        # We don't want to set the review number as the topic
+        if branch_parts[2].isdigit():
+            return
+
         topic = "/".join(branch_parts[2:])
         if VERBOSE:
             print("Using change number %s for the topic of the change "

git_review/tests/test_git_review.py

@@ -383,6 +383,18 @@ class GitReviewTestCase(tests.BaseGitReviewTestCase):
         finally:
             os.environ.update(LANG=lang_env)
 
+    def test_no_topic(self):
+        """Test on change with no topic.
+
+        This will be checked out as 'review/{owner}/{ID}'. We don't want to set
+        the topic to '{ID}'.
+        """
+        self._run_git_review('-s')
+        curr_branch = self._run_git('rev-parse', '--abbrev-ref', 'HEAD')
+        self._run_git('checkout', '-b', 'review/johndoe/123456')
+        self._simple_change('test file modified', 'derp derp derp')
+        self._assert_branch_would_be(curr_branch)
+
     def test_git_review_t(self):
         self._run_git_review('-s')
         self._simple_change('test file modified', 'commit message for bug 654')

releasenotes/notes/ignore-topic-for-master-patches-9ba01c0762d3df65.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    If a patch has no topic, downloading it will result in a topic of
+    ``review/{owner}/{ID}``. Previously, submitting this would then set the
+    topic to ``{ID}``. This was incorrect behavior and is now resolved.