diff -r c73d23cbb129 -r fed2c040764e mercurial/debugcommands.py
--- a/mercurial/debugcommands.py	Wed Dec 13 11:20:52 2017 -0800
+++ b/mercurial/debugcommands.py	Wed Dec 13 11:21:25 2017 -0800
@@ -782,8 +782,7 @@
         elif rheads <= common:
             ui.write(("remote is subset\n"))
 
-    remoterevs, _checkout = hg.addbranchrevs(repo, remote, branches,
-                                             opts.get('remote_head'))
+    remoterevs, _checkout = hg.addbranchrevs(repo, remote, branches, revs=None)
     localrevs = opts['rev']
     doit(localrevs, remoterevs)