--- a/hgext/evolve.py	Thu Jun 18 16:18:29 2015 -0700
+++ b/hgext/evolve.py	Thu Jun 18 16:13:15 2015 -0700
@@ -411,8 +411,9 @@
     cs = set()
     nm = repo.changelog.nodemap
     markerbysubj = repo.obsstore.precursors
+    node = repo.changelog.node
     for r in s:
-        for p in markerbysubj.get(repo[r].node(), ()):
+        for p in markerbysubj.get(node(r), ()):
             pr = nm.get(p[0])
             if pr is not None:
                 cs.add(pr)