--- a/src/topic/revset.py	Wed Sep 30 18:05:27 2015 -0400
+++ b/src/topic/revset.py	Wed Sep 30 18:06:42 2015 -0400
@@ -15,6 +15,8 @@
     if args:
         # match a specific topic
         topic = revset.getstring(args[0], 'topic() argument must be a string')
+        if topic == '.':
+            topic = repo['.'].extra().get('topic', '')
         _kind, _pattern, matcher = revset._stringmatcher(topic)
     else:
         matcher = lambda t: bool(t)

--- a/tests/test-topic.t	Wed Sep 30 18:05:27 2015 -0400
+++ b/tests/test-topic.t	Wed Sep 30 18:06:42 2015 -0400
@@ -450,11 +450,25 @@
   |  summary:     start on fran
   |
 
-Move to fran, note that the topic activates, then deactivate the topic.
-
+Match current topic:
+  $ hg topic
+     fran
+  $ hg log -r 'topic(.)'
+(no output is expected)
   $ hg co fran
   switching to topic fran
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg log -r 'topic(.)'
+  changeset:   9:0469d521db49
+  tag:         tip
+  topic:       fran
+  parent:      3:a53952faf762
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     start on fran
+  
+
+Deactivate the topic.
   $ hg topics
    * fran
   $ hg topics --clear