diff -r a1f694779b2f -r d2ab0db89465 mercurial/changegroup.py
--- a/mercurial/changegroup.py	Mon Aug 06 10:43:05 2018 -0700
+++ b/mercurial/changegroup.py	Mon Aug 06 09:24:35 2018 -0700
@@ -633,7 +633,7 @@
         # order that they're introduced in dramatis personae by the
         # changelog, so what we do is we sort the non-changelog histories
         # by the order in which they are used by the changelog.
-        if self._ellipses and self._clnodetorev:
+        if self._ellipses and self._changelogdone:
             key = lambda n: self._clnodetorev[lookup(n)]
             return [store.rev(n) for n in sorted(nodelist, key=key)]