NetSpec: type-check Function inputs (they must be Top instances)

python/caffe/net_spec.py

@@ -103,6 +103,10 @@ class Function(object):
 
     def __init__(self, type_name, inputs, params):
         self.type_name = type_name
+        for index, input in enumerate(inputs):
+            if not isinstance(input, Top):
+                raise TypeError('%s input %d is not a Top (type is %s)' %
+                                (type_name, index, type(input)))
         self.inputs = inputs
         self.params = params
         self.ntop = self.params.get('ntop', 1)

python/caffe/test/test_net_spec.py

@@ -79,3 +79,11 @@ def test_zero_tops(self):
         net_proto = silent_net()
         net = self.load_net(net_proto)
         self.assertEqual(len(net.forward()), 0)
+
+    def test_type_error(self):
+        """Test that a TypeError is raised when a Function input isn't a Top."""
+        data = L.DummyData(ntop=2)  # data is a 2-tuple of Tops
+        r = r"^Silence input 0 is not a Top \(type is <(type|class) 'tuple'>\)$"
+        with self.assertRaisesRegexp(TypeError, r):
+            L.Silence(data, ntop=0)  # should raise: data is a tuple, not a Top
+        L.Silence(*data, ntop=0)  # shouldn't raise: each elt of data is a Top