fix #5542

Former-commit-id: cf28e7418c2eb07e86923a53ef832ef218e45af1

src/llamafactory/hparams/model_args.py

@@ -15,7 +15,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from dataclasses import asdict, dataclass, field, fields
+from dataclasses import dataclass, field, fields
 from typing import Any, Dict, Literal, Optional, Union
 
 import torch
@@ -308,20 +308,18 @@ class ModelArguments(QuantizationArguments, ProcessorArguments, ExportArguments,
         if self.export_quantization_bit is not None and self.export_quantization_dataset is None:
             raise ValueError("Quantization dataset is necessary for exporting.")
 
-    def to_dict(self) -> Dict[str, Any]:
-        return asdict(self)
-
     @classmethod
-    def copyfrom(cls, old_arg: "Self", **kwargs) -> "Self":
-        arg_dict = old_arg.to_dict()
-        arg_dict.update(**kwargs)
-        for attr in fields(cls):
-            if not attr.init:
-                arg_dict.pop(attr.name)
+    def copyfrom(cls, source: "Self", **kwargs) -> "Self":
+        init_args, lazy_args = {}, {}
+        for attr in fields(source):
+            if attr.init:
+                init_args[attr.name] = getattr(source, attr.name)
+            else:
+                lazy_args[attr.name] = getattr(source, attr.name)
 
-        new_arg = cls(**arg_dict)
-        new_arg.compute_dtype = old_arg.compute_dtype
-        new_arg.device_map = old_arg.device_map
-        new_arg.model_max_length = old_arg.model_max_length
-        new_arg.block_diag_attn = old_arg.block_diag_attn
-        return new_arg
+        init_args.update(kwargs)
+        result = cls(**init_args)
+        for name, value in lazy_args.items():
+            setattr(result, name, value)
+
+        return result