fix(mge/gm): fix missing dtype checking while attach tensors

GitOrigin-RevId: f0aaea99b93472b893eeb3ba35c6293c5f15b122

imperative/python/megengine/autodiff/grad_manager.py

@@ -6,11 +6,11 @@
 # software distributed under the License is distributed on an
 # "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 import weakref
-from collections import OrderedDict
 from typing import Callable, Iterable, List, Union
 
 from ..core._imperative_rt.core2 import pop_scope, push_scope, set_option
 from ..core.autodiff.grad import Grad
+from ..core.tensor.dtype import is_differentible_dtype
 from ..logger import get_logger
 from ..tensor import Tensor
 from ..utils.future import Future
@@ -208,6 +208,10 @@ class GradManager:
 
         for x in tensors:
             assert isinstance(x, Tensor), "Object to be attached should be Tensor"
+            assert is_differentible_dtype(x.dtype), (
+                "Only tensors of floating point dtype can be attached to get gradients, "
+                "get tensor dtype: {} and shape: {}".format(x.dtype, x.shape)
+            )
             spec = self._attach_specs.get(id(x))
             new_attach = spec is None
             if spec is None:

imperative/python/megengine/core/tensor/dtype.py

@@ -38,6 +38,10 @@ def is_bfloat16(dtype):
     return dtype is bfloat16
 
 
+def is_differentible_dtype(dtype):
+    return dtype == np.float32 or dtype == np.float16 or is_bfloat16(dtype)
+
+
 # quantization dtype related
 
 # use namedtuple to make class immutable, comparable and easy to print
@@ -114,7 +118,7 @@ def create_quantized_dtype(
     dtype_meta: QuantDtypeMeta, scale: float, zp: Union[int, None]
 ):
     r"""Get quantized dtype with metadata attribute according to _metadata_dict.
-    
+
     Note that unsigned dtype must have ``zero_point`` and signed dtype must
     not have ``zero_point``, to be consitent with tensor generated by calling
     compiled function from `CompGraph.compile(inputs, outspec)`.

imperative/python/test/unit/autodiff/test_grad_manger.py

@@ -13,6 +13,7 @@ import numpy as np
 import pytest
 
 import megengine as mge
+import megengine.core.tensor.dtype as dtype
 import megengine.distributed as dist
 import megengine.functional as F
 import megengine.module as M
@@ -469,3 +470,18 @@ def test_2nd_grad_with_custom_gradient():
     np.testing.assert_almost_equal(
         x.grad.numpy(), -np.sin(x_np) - np.cos(x_np), decimal=5
     )
+
+
+@pytest.mark.parametrize("invalid_dtype", [np.uint8, np.int8, np.int32])
+def test_attach_invalid_tensor_dtype(invalid_dtype):
+    gm = GradManager()
+    x = mge.tensor([1], dtype=invalid_dtype)
+    with pytest.raises(AssertionError):
+        gm.attach([x])
+
+
+@pytest.mark.parametrize("differentible_dtype", [np.float32, np.float16])
+def test_attach_differentible_tensor_dtype(differentible_dtype):
+    gm = GradManager()
+    x = mge.tensor([1], dtype=differentible_dtype)
+    gm.attach([x])