diff --git a/mercurial/cext/revlog.c b/mercurial/cext/revlog.c
--- a/mercurial/cext/revlog.c
+++ b/mercurial/cext/revlog.c
@@ -2065,6 +2065,12 @@
 	}
 }
 
+static PyObject *index_m_has_node(indexObject *self, PyObject *args)
+{
+	int ret = index_contains(self, args);
+	return PyBool_FromLong((long)ret);
+}
+
 typedef uint64_t bitmask;
 
 /*
@@ -2723,6 +2729,8 @@
     {"clearcaches", (PyCFunction)index_clearcaches, METH_NOARGS,
      "clear the index caches"},
     {"get", (PyCFunction)index_m_get, METH_VARARGS, "get an index entry"},
+    {"has_node", (PyCFunction)index_m_has_node, METH_O,
+     "return True if the node exist in the index"},
     {"computephasesmapsets", (PyCFunction)compute_phases_map_sets, METH_VARARGS,
      "compute phases"},
     {"reachableroots2", (PyCFunction)reachableroots2, METH_VARARGS,
diff --git a/mercurial/pure/parsers.py b/mercurial/pure/parsers.py
--- a/mercurial/pure/parsers.py
+++ b/mercurial/pure/parsers.py
@@ -55,6 +55,10 @@
             nodemap[n] = r
         return nodemap
 
+    def has_node(self, node):
+        """return True if the node exist in the index"""
+        return node in self.nodemap
+
     def _stripnodes(self, start):
         if 'nodemap' in vars(self):
             for r in range(start, len(self)):
diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -213,6 +213,10 @@
             nodemap[n] = r
         return nodemap
 
+    def has_node(self, node):
+        """return True if the node exist in the index"""
+        return node in self.nodemap
+
     def append(self, tup):
         self.nodemap[tup[7]] = len(self)
         super(revlogoldindex, self).append(tup)