fix: Add Pydantic v2 alias support with backward compatibility

This commit fixes Field(alias="...") functionality in Pydantic v2 while
maintaining full backward compatibility with Pydantic v1.

Author: ravishan16

sqlmodel/main.py

@@ -397,8 +397,6 @@ def Field(
     current_schema_extra = schema_extra or {}
     field_info_kwargs = {
         "alias": alias,
-        "validation_alias": validation_alias,
-        "serialization_alias": serialization_alias,
         "title": title,
         "description": description,
         "exclude": exclude,
@@ -433,6 +431,13 @@ def Field(
         **current_schema_extra,
     }
     if IS_PYDANTIC_V2:
+        # Add Pydantic v2 specific parameters
+        field_info_kwargs.update(
+            {
+                "validation_alias": validation_alias,
+                "serialization_alias": serialization_alias,
+            }
+        )
         field_info = FieldInfo(
             default,
             default_factory=default_factory,

tests/test_aliases.py

@@ -97,7 +97,7 @@ def test_dict_default_uses_field_names(
     model: Union[Type[PydanticUser], Type[SQLModelUser]],
 ):
     user = model(fullName="Dana")
-    data = user.model_dump()
+    data = user.dict()
     assert "full_name" in data
     assert "fullName" not in data
     assert data["full_name"] == "Dana"
@@ -111,7 +111,7 @@ def test_dict_default_uses_aliases(
     model: Union[Type[PydanticUser], Type[SQLModelUser]],
 ):
     user = model(fullName="Dana")
-    data = user.model_dump(by_alias=True)
+    data = user.dict(by_alias=True)
     assert "fullName" in data
     assert "full_name" not in data
     assert data["fullName"] == "Dana"
@@ -125,7 +125,7 @@ def test_json_by_alias(
     model: Union[Type[PydanticUser], Type[SQLModelUser]],
 ):
     user = model(fullName="Frank")
-    json_data = user.model_dump_json(by_alias=True)
+    json_data = user.json(by_alias=True)
     assert ('"fullName":"Frank"' in json_data) or ('"fullName": "Frank"' in json_data)
     assert "full_name" not in json_data
 
@@ -169,7 +169,7 @@ def test_serialize_with_serialization_alias(
     model: Union[Type[PydanticUserV2], Type[SQLModelUserV2]],
 ):
     user = model(firstName="Jane")
-    data = user.model_dump(by_alias=True)
+    data = user.dict(by_alias=True)
     assert "f_name" in data
     assert "firstName" not in data
     assert "first_name" not in data