diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -661,7 +661,7 @@
 
     def rev(self, node):
         try:
-            return self._nodecache[node]
+            return self.index.nodemap[node]
         except TypeError:
             raise
         except error.RevlogError: