Fix: dtype cannot be str (#36262)

* fix

* this wan't supposed to be here, revert

* refine tests a bit more

src/transformers/modeling_utils.py

@@ -1252,13 +1252,13 @@ def _get_torch_dtype(
             for key, curr_dtype in torch_dtype.items():
                 if hasattr(config, key):
                     value = getattr(config, key)
+                    curr_dtype = curr_dtype if not isinstance(curr_dtype, str) else getattr(torch, curr_dtype)
                     value.torch_dtype = curr_dtype
             # main torch dtype for modules that aren't part of any sub-config
             torch_dtype = torch_dtype.get("")
+            torch_dtype = torch_dtype if not isinstance(torch_dtype, str) else getattr(torch, torch_dtype)
             config.torch_dtype = torch_dtype
-            if isinstance(torch_dtype, str) and hasattr(torch, torch_dtype):
+            if torch_dtype is None:
-                torch_dtype = getattr(torch, torch_dtype)
-            elif torch_dtype is None:
                 torch_dtype = torch.float32
         else:
             raise ValueError(
@@ -1269,7 +1269,7 @@ def _get_torch_dtype(
         dtype_orig = cls._set_default_torch_dtype(torch_dtype)
     else:
         # set fp32 as the default dtype for BC
-        default_dtype = str(torch.get_default_dtype()).split(".")[-1]
+        default_dtype = torch.get_default_dtype()
         config.torch_dtype = default_dtype
         for key in config.sub_configs.keys():
             value = getattr(config, key)

tests/utils/test_modeling_utils.py

@@ -482,9 +482,11 @@ class ModelUtilsTest(TestCasePlus):
         # test that from_pretrained works with torch_dtype being strings like "float32" for PyTorch backend
         model = AutoModel.from_pretrained(TINY_T5, torch_dtype="float32")
         self.assertEqual(model.dtype, torch.float32)
+        self.assertIsInstance(model.config.torch_dtype, torch.dtype)
 
         model = AutoModel.from_pretrained(TINY_T5, torch_dtype="float16")
         self.assertEqual(model.dtype, torch.float16)
+        self.assertIsInstance(model.config.torch_dtype, torch.dtype)
 
         # torch.set_default_dtype() supports only float dtypes, so will fail with non-float type
         with self.assertRaises(ValueError):
@@ -495,14 +497,22 @@ class ModelUtilsTest(TestCasePlus):
         Test that from_pretrained works with torch_dtype being as a dict per each sub-config in composite config
         Tiny-Llava has saved auto dtype as `torch.float32` for all modules.
         """
+        # Load without dtype specified
+        model = LlavaForConditionalGeneration.from_pretrained(TINY_LLAVA)
+        self.assertEqual(model.language_model.dtype, torch.float32)
+        self.assertEqual(model.vision_tower.dtype, torch.float32)
+        self.assertIsInstance(model.config.torch_dtype, torch.dtype)
+
         # should be able to set torch_dtype as a simple string and the model loads it correctly
         model = LlavaForConditionalGeneration.from_pretrained(TINY_LLAVA, torch_dtype="float32")
         self.assertEqual(model.language_model.dtype, torch.float32)
         self.assertEqual(model.vision_tower.dtype, torch.float32)
+        self.assertIsInstance(model.config.torch_dtype, torch.dtype)
 
         model = LlavaForConditionalGeneration.from_pretrained(TINY_LLAVA, torch_dtype=torch.float16)
         self.assertEqual(model.language_model.dtype, torch.float16)
         self.assertEqual(model.vision_tower.dtype, torch.float16)
+        self.assertIsInstance(model.config.torch_dtype, torch.dtype)
 
         # should be able to set torch_dtype as a dict for each sub-config
         model = LlavaForConditionalGeneration.from_pretrained(
@@ -511,6 +521,7 @@ class ModelUtilsTest(TestCasePlus):
         self.assertEqual(model.language_model.dtype, torch.float32)
         self.assertEqual(model.vision_tower.dtype, torch.float16)
         self.assertEqual(model.multi_modal_projector.linear_1.weight.dtype, torch.bfloat16)
+        self.assertIsInstance(model.config.torch_dtype, torch.dtype)
 
         # should be able to set the values as torch.dtype (not str)
         model = LlavaForConditionalGeneration.from_pretrained(
@@ -519,6 +530,7 @@ class ModelUtilsTest(TestCasePlus):
         self.assertEqual(model.language_model.dtype, torch.float32)
         self.assertEqual(model.vision_tower.dtype, torch.float16)
         self.assertEqual(model.multi_modal_projector.linear_1.weight.dtype, torch.bfloat16)
+        self.assertIsInstance(model.config.torch_dtype, torch.dtype)
 
         # should be able to set the values in configs directly and pass it to `from_pretrained`
         config = copy.deepcopy(model.config)
@@ -529,6 +541,7 @@ class ModelUtilsTest(TestCasePlus):
         self.assertEqual(model.language_model.dtype, torch.float32)
         self.assertEqual(model.vision_tower.dtype, torch.bfloat16)
         self.assertEqual(model.multi_modal_projector.linear_1.weight.dtype, torch.float16)
+        self.assertIsInstance(model.config.torch_dtype, torch.dtype)
 
         # but if the model has `_keep_in_fp32_modules` then those modules should be in fp32 no matter what
         LlavaForConditionalGeneration._keep_in_fp32_modules = ["multi_modal_projector"]
@@ -536,6 +549,7 @@ class ModelUtilsTest(TestCasePlus):
         self.assertEqual(model.language_model.dtype, torch.float32)
         self.assertEqual(model.vision_tower.dtype, torch.bfloat16)
         self.assertEqual(model.multi_modal_projector.linear_1.weight.dtype, torch.float32)
+        self.assertIsInstance(model.config.torch_dtype, torch.dtype)
 
         # torch.set_default_dtype() supports only float dtypes, so will fail with non-float type
         with self.assertRaises(ValueError):