Pass FieldInfo straight through to create_model() if no need to c…

…hange. Where a field is neither excluded, nor mapped the least surprising thing would be that the field stays the same.
litestar-org · May 24, 2022 · 2e5b1f6 · 2e5b1f6
1 parent 39d2ffd
commit 2e5b1f6
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Showing 2 changed files with 14 additions and 5 deletions.
diff --git a/starlite/dto.py b/starlite/dto.py
@@ -137,12 +137,16 @@ def create_obj(data: MyClassDTO) -> MyClass:
                         field_name, field_type = mapping
                     else:
                         field_name = mapping
-                if model_field.field_info.default not in (Undefined, None, ...):
-                    field_definitions[field_name] = (field_type, model_field.default)
-                elif model_field.required or not model_field.allow_none:
-                    field_definitions[field_name] = (field_type, ...)
+                    if model_field.field_info.default not in (Undefined, None, ...):
+                        field_definitions[field_name] = (field_type, model_field.default)
+                    elif model_field.required or not model_field.allow_none:
+                        field_definitions[field_name] = (field_type, ...)
+                    else:
+                        field_definitions[field_name] = (field_type, None)
                 else:
-                    field_definitions[field_name] = (field_type, None)
+                    # prevents losing Optional
+                    field_type = Optional[field_type] if model_field.allow_none else field_type
+                    field_definitions[field_name] = (field_type, model_field.field_info)
         dto = cast(Type[DTO[T]], create_model(name, __base__=DTO, **field_definitions))  # type: ignore
         dto.dto_source_model = source
         dto.dto_source_plugin = plugin

diff --git a/tests/test_dto_factory.py b/tests/test_dto_factory.py
@@ -195,3 +195,8 @@ def test_dto_factory_preserves_field_allow_none_false() -> None:
     assert Example.__fields__["password"].allow_none is False
     ExampleDTO = DTOFactory()("ExampleDTO", Example)
     assert ExampleDTO.__fields__["password"].allow_none is False
+
+
+def test_dto_factory_preserves_field_info_where_unnecessary_to_change() -> None:
+    ExampleDTO = DTOFactory(plugins=[])("ExampleDTO", PydanticPet, exclude=[], field_mapping={}, field_definitions={})
+    assert PydanticPet.__fields__["name"].field_info is ExampleDTO.__fields__["name"].field_info