FIX [`bnb`] Make `unexpected_keys` optional (#29420)

* make `unexpected_keys` optional

* push

* Apply suggestions from code review
Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>

---------
Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>

src/transformers/modeling_utils.py

@@ -3769,7 +3769,7 @@ class PreTrainedModel(nn.Module, ModuleUtilsMixin, GenerationMixin, PushToHubMix
                     ):
                         set_module_tensor_to_device(model, key, "cpu", value)
                     else:
-                        hf_quantizer.create_quantized_param(model, value, key, "cpu", state_dict)
+                        hf_quantizer.create_quantized_param(model, value, key, "cpu", state_dict, unexpected_keys)
 
         # retrieve uninitialized modules and initialize before maybe overriding that with the pretrained weights.
         if _fast_init:

src/transformers/quantizers/quantizer_bnb_4bit.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import importlib
-from typing import TYPE_CHECKING, Any, Dict, List, Union
+from typing import TYPE_CHECKING, Any, Dict, List, Optional, Union
 
 from packaging import version
 
@@ -143,7 +143,7 @@ class Bnb4BitHfQuantizer(HfQuantizer):
         param_name: str,
         target_device: "torch.device",
         state_dict: Dict[str, Any],
-        unexpected_keys: List[str],
+        unexpected_keys: Optional[List[str]] = None,
     ):
         """
         combines logic from _load_state_dict_into_meta_model and .integrations.bitsandbytes.py::set_module_quantized_tensor_to_device()
@@ -198,6 +198,7 @@ class Bnb4BitHfQuantizer(HfQuantizer):
             for k, v in state_dict.items():
                 if param_name + "." in k:
                     quantized_stats[k] = v
+                    if unexpected_keys is not None and k in unexpected_keys:
                         unexpected_keys.remove(k)
 
             new_value = bnb.nn.Params4bit.from_prequantized(

src/transformers/quantizers/quantizer_bnb_8bit.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import importlib
-from typing import TYPE_CHECKING, Any, Dict, List, Union
+from typing import TYPE_CHECKING, Any, Dict, List, Optional, Union
 
 from packaging import version
 
@@ -162,7 +162,7 @@ class Bnb8BitHfQuantizer(HfQuantizer):
         param_name: str,
         target_device: "torch.device",
         state_dict: Dict[str, Any],
-        unexpected_keys: List[str],
+        unexpected_keys: Optional[List[str]] = None,
     ):
         """
         combines logic from _load_state_dict_into_meta_model and .integrations.bitsandbytes.py::set_module_quantized_tensor_to_device()
@@ -207,6 +207,7 @@ class Bnb8BitHfQuantizer(HfQuantizer):
         module._parameters[tensor_name] = new_value
         if fp16_statistics is not None:
             setattr(module.weight, "SCB", fp16_statistics.to(target_device))
+            if unexpected_keys is not None:
                 unexpected_keys.remove(fp16_statistics_key)
 
     def _process_model_after_weight_loading(self, model: "PreTrainedModel", **kwargs):