Fix get_canonical_form_slice when lengths are numpy integers

pytensor/tensor/subtensor.py

@@ -325,7 +325,7 @@ def get_canonical_form_slice(
         and is_step_constant
         and is_length_constant
     ):
-        assert isinstance(length, int)
+        assert isinstance(length, int | np.integer)
         _start, _stop, _step = slice(start, stop, step).indices(length)
         if _start <= _stop and _step >= 1:
             return slice(_start, _stop, _step), 1

tests/tensor/test_subtensor.py

@@ -154,8 +154,11 @@ class TestGetCanonicalFormSlice:
         assert isinstance(res[0].owner.op, ptb.ScalarFromTensor)
         assert res[1] == 1
 
-    def test_all_integer(self):
-        res = get_canonical_form_slice(slice(1, 5, 2), 7)
+    @pytest.mark.parametrize("int_fn", [int, np.int64, as_tensor, as_scalar])
+    def test_all_integer(self, int_fn):
+        res = get_canonical_form_slice(
+            slice(int_fn(1), int_fn(5), int_fn(2)), int_fn(7)
+        )
         assert isinstance(res[0], slice)
         assert res[1] == 1