diff -r 0e46b92b37b1 -r 858a12846f4f mercurial/debugcommands.py
--- a/mercurial/debugcommands.py	Thu Aug 16 19:40:46 2018 +0000
+++ b/mercurial/debugcommands.py	Thu Aug 16 19:47:30 2018 +0000
@@ -794,7 +794,7 @@
                 cl = repo.changelog
                 clnode = cl.node
                 dag = dagutil.revlogdag(cl)
-                all = dag.ancestorset(dag.internalizeall(common))
+                all = dag.ancestorset(cl.rev(n) for n in common)
                 common = {clnode(r) for r in dag.headsetofconnecteds(all)}
         else:
             nodes = None