diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -509,6 +509,16 @@
         self._sparsesignaturecache = {}
         # Signature to cached matcher instance.
         self._sparsematchercache = {}
+        # hidden hashed which should be visible
+        self._visibilityexceptions = set()
+
+    def addvisibilityexceptions(self, exceptions):
+        """ adds hidden revs which should be visible to set of exceptions """
+        self._visibilityexceptions.update(exceptions)
+
+    def getvisibilityexceptions(self):
+        """ returns the set of hidden revs which should be visible """
+        return self._visibilityexceptions
 
     def _getvfsward(self, origfunc):
         """build a ward for self.vfs"""