--- a/hgext3rd/topic/evolvebits.py	Wed Sep 27 16:24:44 2017 +0200
+++ b/hgext3rd/topic/evolvebits.py	Sat Sep 30 11:11:04 2017 +0100
@@ -81,8 +81,16 @@
                  obs)
         obs = obs.parents()[0]
         newer = compat.successorssets(repo, obs.node())
-    if len(newer) > 1 or len(newer[0]) > 1:
+    if 1 < len(newer):
+        # divergence case
+        # we should pick as arbitrary one
         raise MultipleSuccessorsError(newer)
+    elif 1 < len(newer[0]):
+        splitheads = list(repo.revs('heads(%ln::%ln)', newer[0], newer[0]))
+        if 1 < len(splitheads):
+            # split case, See if we can make sense of it.
+            raise MultipleSuccessorsError(newer)
+        return splitheads[0]
 
     return repo[newer[0][0]].rev()