Description
It is from my question on StackOverflow: https://stackoverflow.com/questions/75096188/typeerror-when-creating-a-marshmallow-schema-from-dataclass-inherited-from-gener?noredirect=1#comment132530258_75096188
I'm trying to create a marshmallow schema from dataclass which is inherited from generic type:
users_schema = marshmallow_dataclass.class_schema(Users)()
This is my code:
from dataclasses import dataclass
from typing import Generic, List, TypeVar
T = TypeVar("T")
@dataclass
class Pagination(Generic[T]):
items: List[T]
@dataclass
class User:
pass
@dataclass
class Users(Pagination[User]):
pass
However I get this traceback:
src/c1client/entities/schemas.py:39: in <module>
users_schema = marshmallow_dataclass.class_schema(Users)()
../../../.venvs/cva-user-service/lib/python3.9/site-packages/marshmallow_dataclass/__init__.py:357: in class_schema
return _internal_class_schema(clazz, base_schema, clazz_frame)
../../../.venvs/cva-user-service/lib/python3.9/site-packages/marshmallow_dataclass/__init__.py:403: in _internal_class_schema
attributes.update(
../../../.venvs/cva-user-service/lib/python3.9/site-packages/marshmallow_dataclass/__init__.py:406: in <genexpr>
field_for_schema(
../../../.venvs/cva-user-service/lib/python3.9/site-packages/marshmallow_dataclass/__init__.py:701: in field_for_schema
generic_field = _field_for_generic_type(typ, base_schema, typ_frame, **metadata)
../../../.venvs/cva-user-service/lib/python3.9/site-packages/marshmallow_dataclass/__init__.py:505: in _field_for_generic_type
child_type = field_for_schema(
../../../.venvs/cva-user-service/lib/python3.9/site-packages/marshmallow_dataclass/__init__.py:719: in field_for_schema
if issubclass(typ, Enum):
E TypeError: issubclass() arg 1 must be a class
When I print typ variable from the traceback it is printed like ~T which is really not a class.
Also when I make Pagination class concrete - not generic, it works. So the problem is related to Generic.
Any ideas what could I do to make it work?