Fix iterator over symbol when multiple children have the same name

python/mxnet/symbol/symbol.py

@@ -90,7 +90,7 @@ def __iter__(self):
         <Symbol d>
         <Symbol _plus0>
         """
-        return (self[i] for i in self.list_outputs())
+        return (self[i] for i in range(len(self)))
 
     def __add__(self, other):
         """x.__add__(y) <=> x+y

tests/python/unittest/test_symbol.py

@@ -367,6 +367,11 @@ def test_simple_bind_gradient_graph_possible_with_cycle():
     res = data + data + data + data + data + data + data + data
     res.simple_bind(ctx=mx.cpu(), data=(1,))
 
+def test_children_same_name():
+    a = mx.sym.Variable('data')
+    b = a + a
+    for c in b.get_children():
+        pass
 
 if __name__ == '__main__':
     import nose