diff -r 71d8b4d91616 -r 07faf5c65190 mercurial/branchmap.py
--- a/mercurial/branchmap.py	Sat Apr 20 07:29:07 2019 -0700
+++ b/mercurial/branchmap.py	Fri Apr 19 23:13:28 2019 +0300
@@ -341,7 +341,7 @@
                 cachekey.append(hex(self.filteredhash))
             f.write(" ".join(cachekey) + '\n')
             nodecount = 0
-            for label, nodes in sorted(self.iteritems()):
+            for label, nodes in sorted(self._entries.iteritems()):
                 label = encoding.fromlocal(label)
                 for node in nodes:
                     nodecount += 1