Validate test values using a tensor's type

tests/gof/test_compute_test_value.py

@@ -167,14 +167,16 @@ class TestComputeTestValue:
 
     @theano.change_flags(compute_test_value="raise")
     def test_incorrect_type(self):
-        x = tt.fmatrix("x")
-        # Incorrect dtype (float64) for test_value
-        x.tag.test_value = np.random.rand(3, 4)
-        y = tt.dmatrix("y")
-        y.tag.test_value = np.random.rand(4, 5)
 
+        x = tt.vector("x")
         with pytest.raises(TypeError):
-            tt.dot(x, y)
+            # Incorrect shape for test value
+            x.tag.test_value = np.empty((2, 2))
+
+        x = tt.fmatrix("x")
+        with pytest.raises(TypeError):
+            # Incorrect dtype (float64) for test value
+            x.tag.test_value = np.random.rand(3, 4)
 
     @theano.change_flags(compute_test_value="raise")
     def test_overided_function(self):

theano/gof/graph.py

@@ -383,7 +383,7 @@ class Variable(Node):
     def __init__(self, type, owner=None, index=None, name=None):
         super(Variable, self).__init__()
 
-        self.tag = utils.Scratchpad()
+        self.tag = utils.ValidatingScratchpad("test_value", type.filter)
 
         self.type = type
         if owner is not None and not isinstance(owner, Apply):

theano/gof/utils.py

@@ -259,6 +259,23 @@ class Scratchpad(object):
             print("  %s: %s" % (k, v))
 
 
+class ValidatingScratchpad(Scratchpad):
+    """This `Scratchpad` validates attribute values."""
+
+    def __init__(self, attr, attr_filter):
+        super().__init__()
+
+        object.__setattr__(self, "attr", attr)
+        object.__setattr__(self, "attr_filter", attr_filter)
+
+    def __setattr__(self, attr, obj):
+
+        if getattr(self, "attr", None) == attr:
+            obj = self.attr_filter(obj)
+
+        return object.__setattr__(self, attr, obj)
+
+
 class D:
     def __init__(self, **d):
         self.__dict__.update(d)

theano/tensor/opt.py

@@ -7743,7 +7743,10 @@ def local_elemwise_fusion_op(op_class, max_input_fct=lambda node: 32, maker=None
                                 if tv.size > 0:
                                     tmp.tag.test_value = tv.flatten()[0]
                                 else:
-                                    tmp.tag.test_value = tv
+                                    _logger.warning(
+                                        "Cannot construct a scalar test value"
+                                        " from a test value with no size: {}".format(ii)
+                                    )
                             except AttributeError:
                                 pass