--- a/mercurial/subrepoutil.py	Sun Oct 06 19:25:18 2019 -0400
+++ b/mercurial/subrepoutil.py	Mon Oct 07 00:04:04 2019 -0400
@@ -20,6 +20,7 @@
     filemerge,
     pathutil,
     phases,
+    pycompat,
     util,
 )
 from .utils import stringutil
@@ -162,7 +163,7 @@
         repo.ui.debug(b"  subrepo %s: %s %s\n" % (s, msg, r))
 
     promptssrc = filemerge.partextras(labels)
-    for s, l in sorted(s1.iteritems()):
+    for s, l in sorted(pycompat.iteritems(s1)):
         a = sa.get(s, nullstate)
         ld = l  # local state with possible dirty flag for compares
         if wctx.sub(s).dirty():