diff -r e47bd4c71c5e -r 70c52800940b mercurial/hg.py
--- a/mercurial/hg.py	Sun Apr 01 23:21:17 2018 -0700
+++ b/mercurial/hg.py	Sun Apr 01 23:27:50 2018 -0700
@@ -957,7 +957,7 @@
     ui.status(_('comparing with %s\n') % util.hidepassword(dest))
     revs, checkout = addbranchrevs(repo, repo, branches, opts.get('rev'))
     if revs:
-        revs = [repo.lookup(rev) for rev in scmutil.revrange(repo, revs)]
+        revs = [repo[rev].node() for rev in scmutil.revrange(repo, revs)]
 
     other = peer(repo, opts, dest)
     outgoing = discovery.findcommonoutgoing(repo, other, revs,