Bug: DTO: a computed field that returns optional structure causes exception on None (experimental_codegen bug?) #4458
Description
Description
When using a DTO in connection with a computed field, if the field returns an optional structure, if the result is None litestar produces following error:
TypeError: Missing required argument 'full_error'
Here's trace back:
Traceback (most recent call last):
File "[...]/lib/python3.12/site-packages/litestar/middleware/_internal/exceptions/middleware.py", line 158, in __call__
await self.app(scope, receive, capture_response_started)
File "[...]/lib/python3.12/site-packages/litestar/_asgi/asgi_router.py", line 100, in __call__
await asgi_app(scope, receive, send)
File "[...]/lib/python3.12/site-packages/litestar/routes/http.py", line 81, in handle
response = await self._get_response_for_request(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "[...]/lib/python3.12/site-packages/litestar/routes/http.py", line 133, in _get_response_for_request
return await self._call_handler_function(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "[...]/lib/python3.12/site-packages/litestar/routes/http.py", line 184, in _call_handler_function
return await route_handler.to_response(app=scope["litestar_app"], data=response_data, request=request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "[...]/lib/python3.12/site-packages/litestar/handlers/http_handlers/base.py", line 581, in to_response
data = return_dto_type(request).data_to_encodable_type(data)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "[...]/lib/python3.12/site-packages/litestar/dto/base_dto.py", line 124, in data_to_encodable_type
return backend.encode_data(data)
^^^^^^^^^^^^^^^^^^^^^^^^^
File "[...]/lib/python3.12/site-packages/litestar/dto/_codegen_backend.py", line 153, in encode_data
return cast("LitestarEncodableType", self._encode_data(data))
^^^^^^^^^^^^^^^^^^^^^^^
File "dto_transfer_function_766f5a0d34e2", line 51, in func
tmp_return_type_0 = destination_type_0(**unstructured_data_0)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: Missing required argument 'status'
Disabling experimental_codegen_backend makes the code work as expected.
URL to code causing the issue
No response
MCVE
from typing import Optional
from litestar import Litestar, get
from litestar.dto import DTOConfig
from litestar.logging import LoggingConfig
from litestar.plugins.pydantic import PydanticDTO
from pydantic import BaseModel, computed_field
class Status(BaseModel):
a: str
b: str
class Result(BaseModel):
@computed_field
@property
def status(self) -> Optional[Status]:
return None
class ResultDTO(PydanticDTO[Result]):
config = DTOConfig(
include={'status'},
# experimental_codegen_backend=False,
)
@get("/", return_dto=ResultDTO)
async def hello() -> Result:
return Result()
app = Litestar(route_handlers=[hello], logging_config=LoggingConfig(log_exceptions='always'))Steps to reproduce
- start the application
- request the root page
- see exception in the terminal
- uncomment
experimental_codegen_backend=False - see code working correctly
Screenshots
No response
Logs
Litestar Version
v2.17.0
Platform
- Linux
- Mac
- Windows
- Other (Please specify in the description above)