Description
If the return type of a route has more than one field which is generic on one or two (possibly more?) types the expected serialization does not occur.
TL;DR
Current behavior: Serialization Fails for all routes except route-0
Expected behavior: Serialization Success
URL to code causing the issue
No response
MCVE
from dataclasses import dataclass
from typing import Generic, TypeVar
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column
from litestar import Response, get
from litestar.contrib.sqlalchemy.plugins import SQLAlchemySerializationPlugin
from litestar.testing import create_test_client
class Base(DeclarativeBase):
pass
class SomeTable(Base):
__tablename__ = "something"
id: Mapped[int] = mapped_column(primary_key=True)
col: Mapped[str]
T = TypeVar("T")
U = TypeVar("U")
@dataclass
class GenericOnOne(Generic[T]):
val_1: list[T]
@dataclass
class GenericOnTwo(Generic[T, U]):
val_1: list[T]
val_2: list[U]
@dataclass
class GenericOnOneButTwoFields(Generic[T]):
val_1: list[T]
val_2: list[T]
t = [SomeTable(id=1, col="Hello, World!")]
@get("route-0")
async def route_0() -> GenericOnOne[SomeTable]:
# nothing wrong here, just to show it works
return GenericOnOne(val_1=t)
@get("route-1")
async def route_1() -> GenericOnTwo[SomeTable, SomeTable]:
# fails to serialize if it has two fields generic on different types
return GenericOnTwo(val_1=t, val_2=t)
@get("route-2")
async def route_2() -> GenericOnOneButTwoFields[SomeTable]:
# fails to serialize if has two fields generic on the same types
return GenericOnOneButTwoFields(val_1=t, val_2=t)
@get("route-3")
async def route_3() -> Response[GenericOnOne[SomeTable]]:
# fails to serialize when wrapped with another Generic
return Response(GenericOnOne(val_1=t))
with create_test_client(
[route_0, route_1, route_2, route_3], plugins=[SQLAlchemySerializationPlugin()]
) as client:
response_0 = client.get("route-0")
assert response_0.status_code == 200
response_1 = client.get("route-1")
assert response_1.status_code == 500
response_2 = client.get("route-2")
assert response_2.status_code == 500
response_3 = client.get("route-3")
assert response_3.status_code == 500Steps to reproduce
Run the codeScreenshots
""Logs
Traceback (most recent call last):
File "litestar/litestar/serialization/msgspec_hooks.py", line 162, in encode_json
return msgspec.json.encode(value, enc_hook=serializer) if serializer else _msgspec_json_encoder.encode(value)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "litestar/litestar/serialization/msgspec_hooks.py", line 92, in default_serializer
raise TypeError(f"Unsupported type: {type(value)!r}")
TypeError: Unsupported type: <class '__main__.SomeTable'>
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "litestar/litestar/middleware/_internal/exceptions/middleware.py", line 158, in __call__
await self.app(scope, receive, capture_response_started)
File "litestar/litestar/_asgi/asgi_router.py", line 99, in __call__
await asgi_app(scope, receive, send)
File "litestar/litestar/routes/http.py", line 80, in handle
response = await self._get_response_for_request(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "litestar/litestar/routes/http.py", line 132, in _get_response_for_request
return await self._call_handler_function(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "litestar/litestar/routes/http.py", line 156, in _call_handler_function
response: ASGIApp = await route_handler.to_response(app=scope["app"], data=response_data, request=request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "litestar/litestar/handlers/http_handlers/base.py", line 557, in to_response
return await response_handler(app=app, data=data, request=request) # type: ignore[call-arg]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "litestar/litestar/handlers/http_handlers/_utils.py", line 79, in handler
return response.to_asgi_response(app=None, request=request, headers=normalize_headers(headers), cookies=cookies) # pyright: ignore
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "litestar/litestar/response/base.py", line 451, in to_asgi_response
body=self.render(self.content, media_type, get_serializer(type_encoders)),
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "litestar/litestar/response/base.py", line 392, in render
return encode_json(content, enc_hook)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "litestar/litestar/serialization/msgspec_hooks.py", line 164, in encode_json
raise SerializationException(str(msgspec_error)) from msgspec_error
litestar.exceptions.base_exceptions.SerializationException: Unsupported type: <class '__main__.SomeTable'>Litestar Version
84f51c8 (main as of issue creation)
Platform
- Linux
- Mac
- Windows
- Other (Please specify in the description above)
litestar-org / litestar
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