include_subclasses does not support dataclasses #426
Description
- cattrs version: 23.1.2
- Python version: 3.9
- Operating System: Linux
Description
According to the documentation, include_subclasses() supports both attrs and dataclasses. However, when I change the example to use dataclasses, I get an error:
from dataclasses import dataclass
from cattrs.strategies import include_subclasses
from cattrs import Converter
@dataclass
class Parent:
a: int
@dataclass
class Child(Parent):
b: str
converter = Converter()
include_subclasses(Parent, converter)produces
Traceback (most recent call last):
File "/home/eltoder/dev/scratch/cattrs_dc.py", line 14, in <module>
include_subclasses(Parent, converter)
File "/home/eltoder/.local/share/ext-python/python-3.9.16.146/lib/python3.9/site-packages/cattrs/strategies/_subclasses.py", line 73, in include_subclasses
_include_subclasses_without_union_strategy(
File "/home/eltoder/.local/share/ext-python/python-3.9.16.146/lib/python3.9/site-packages/cattrs/strategies/_subclasses.py", line 111, in _include_subclasses_without_union_strategy
dis_fn = converter._get_dis_func(subclass_union)
File "/home/eltoder/.local/share/ext-python/python-3.9.16.146/lib/python3.9/site-packages/cattrs/converters.py", line 756, in _get_dis_func
return create_uniq_field_dis_func(*union_types)
File "/home/eltoder/.local/share/ext-python/python-3.9.16.146/lib/python3.9/site-packages/cattrs/disambiguators.py", line 20, in create_uniq_field_dis_func
cls_and_attrs = [
File "/home/eltoder/.local/share/ext-python/python-3.9.16.146/lib/python3.9/site-packages/cattrs/disambiguators.py", line 21, in <listcomp>
(cl, set(at.name for at in fields(get_origin(cl) or cl))) for cl in classes
File "/home/eltoder/.local/share/ext-python/python-3.9.16.146/lib/python3.9/site-packages/attr/_make.py", line 1944, in fields
raise NotAnAttrsClassError(f"{cls!r} is not an attrs-decorated class.")
attr.exceptions.NotAnAttrsClassError: <class '__main__.Child'> is not an attrs-decorated class.
It does work if I use union_strategy:
from cattrs.strategies import configure_tagged_union
include_subclasses(Parent, converter, union_strategy=configure_tagged_union)Additionally, when union_strategy=configure_tagged_union is used, it would be nice to avoid using __subclasses__ so that new classes can be added dynamically. Let me know if you want me to open a separate issue for this.