--- a/mercurial/formatter.py	Thu Mar 15 21:52:47 2018 +0900
+++ b/mercurial/formatter.py	Sat Mar 17 17:41:07 2018 +0900
@@ -514,6 +514,8 @@
         mapping = {}
         if self._hasctx(newmapping):
             mapping['revcache'] = {}  # per-ctx cache
+        if 'node' in origmapping and 'node' in newmapping:
+            mapping['originalnode'] = origmapping['node']
         return mapping
 
     def _getsome(self, context, mapping, key):