♻️ Cleanup more, remove unneeded code

fastapi/_compat/v2.py

@@ -169,11 +169,11 @@ class ModelField:
         values: dict[str, Any] = {},  # noqa: B006
         *,
         loc: tuple[Union[int, str], ...] = (),
-    ) -> tuple[Any, Union[list[dict[str, Any]], None]]:
+    ) -> tuple[Any, list[dict[str, Any]]]:
         try:
             return (
                 self._type_adapter.validate_python(value, from_attributes=True),
-                None,
+                [],
             )
         except ValidationError as exc:
             return None, _regenerate_error_with_loc(
@@ -359,7 +359,7 @@ def serialize_sequence_value(*, field: ModelField, value: Any) -> Sequence[Any]:
     return shared.sequence_annotation_to_type[origin_type](value)  # type: ignore[no-any-return,index]
 
 
-def get_missing_field_error(loc: tuple[str, ...]) -> dict[str, Any]:
+def get_missing_field_error(loc: tuple[Union[int, str], ...]) -> dict[str, Any]:
     error = ValidationError.from_exception_data(
         "Field required", [{"type": "missing", "loc": loc, "input": {}}]
     ).errors(include_url=False)[0]

fastapi/dependencies/utils.py

@@ -717,11 +717,7 @@ def _validate_value_with_model_field(
             return None, [get_missing_field_error(loc=loc)]
         else:
             return deepcopy(field.default), []
-    v_, errors_ = field.validate(value, values, loc=loc)
-    if isinstance(errors_, list):
-        return None, errors_
-    else:
-        return v_, []
+    return field.validate(value, values, loc=loc)
 
 
 def _is_json_field(field: ModelField) -> bool:

fastapi/routing.py

@@ -277,15 +277,12 @@ async def serialize_response(
     endpoint_ctx: Optional[EndpointContext] = None,
 ) -> Any:
     if field:
-        errors = []
         if is_coroutine:
-            value, errors_ = field.validate(response_content, {}, loc=("response",))
+            value, errors = field.validate(response_content, {}, loc=("response",))
         else:
-            value, errors_ = await run_in_threadpool(
+            value, errors = await run_in_threadpool(
                 field.validate, response_content, {}, loc=("response",)
             )
-        if isinstance(errors_, list):
-            errors.extend(errors_)
         if errors:
             ctx = endpoint_ctx or EndpointContext()
             raise ResponseValidationError(