diff --git a/mercurial/cext/parsers.c b/mercurial/cext/parsers.c
--- a/mercurial/cext/parsers.c
+++ b/mercurial/cext/parsers.c
@@ -667,7 +667,7 @@ void dirs_module_init(PyObject *mod);
 void manifest_module_init(PyObject *mod);
 void revlog_module_init(PyObject *mod);
 
-static const int version = 13;
+static const int version = 14;
 
 static void module_init(PyObject *mod)
 {
diff --git a/mercurial/cext/revlog.c b/mercurial/cext/revlog.c
--- a/mercurial/cext/revlog.c
+++ b/mercurial/cext/revlog.c
@@ -2065,6 +2065,14 @@ static int index_contains(indexObject *s
 	}
 }
 
+static PyObject *index_m_has_node(indexObject *self, PyObject *args)
+{
+	int ret = index_contains(self, args);
+	if (ret < 0)
+		return NULL;
+	return PyBool_FromLong((long)ret);
+}
+
 typedef uint64_t bitmask;
 
 /*
@@ -2723,6 +2731,8 @@ static PyMethodDef index_methods[] = {
     {"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/policy.py b/mercurial/policy.py
--- a/mercurial/policy.py
+++ b/mercurial/policy.py
@@ -80,7 +80,7 @@ def _importfrom(pkgname, modname):
     ('cext', 'bdiff'): 3,
     ('cext', 'mpatch'): 1,
     ('cext', 'osutil'): 4,
-    ('cext', 'parsers'): 13,
+    ('cext', 'parsers'): 14,
 }
 
 # map import request to other package or module
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 @@ class BaseIndexObject(object):
             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 @@ class revlogoldindex(list):
             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)