Add small test case for #140230 (#140850)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/140850
Approved by: https://github.com/malfet
ghstack dependencies: #140739, #140740

test/test_serialization.py

@@ -4449,6 +4449,34 @@ class TestSerialization(TestCase, SerializationMixin):
             ) if not should_import else None
             self._attempt_load_from_subprocess(filename, import_string, err_msg)
 
+    @parametrize("dtype", all_types_and_complex_and(torch.half, torch.bfloat16, torch.bool))
+    @parametrize("weights_only", [True, False])
+    def test_save_load_preserves_dtype(self, dtype, weights_only):
+        class MyModule(torch.nn.Module):
+            def __init__(self, t):
+                super().__init__()
+                requires_grad = torch.is_floating_point(t) or torch.is_complex(t)
+                self.param = torch.nn.Parameter(t, requires_grad=requires_grad)
+
+        if dtype.is_floating_point or dtype.is_complex:
+            t = torch.randn(10, dtype=dtype)
+            sd = MyModule(t).state_dict()
+        elif dtype is torch.bool:
+            t = torch.randn(10) > 0
+            sd = MyModule(t).state_dict()
+        else:
+            iinfo = torch.iinfo(dtype)
+            t = torch.randint(iinfo.min, iinfo.max, (10,), dtype=dtype)
+            sd = MyModule(t).state_dict()
+        sd_save = {'t': t, 'sd': sd, 'i' : t[0].item()}
+
+        with tempfile.NamedTemporaryFile() as f:
+            torch.save(sd_save, f)
+            f.seek(0)
+            loaded_sd = torch.load(f, weights_only=weights_only)
+            self.assertEqual(sd_save, loaded_sd)
+
+
     def run(self, *args, **kwargs):
         with serialization_method(use_zip=True):
             return super().run(*args, **kwargs)

torch/_weights_only_unpickler.py

@@ -168,6 +168,7 @@ def _get_allowed_globals():
         "_codecs.encode": encode,  # for bytes
         "builtins.bytearray": bytearray,  # for bytearray
         "builtins.set": set,  # for set
+        "builtins.complex": complex,  # for complex
     }
 
     # dtype