Cannot structure to list[str] field on Python 3.8 #279
Description
- cattrs version: 22.1.0 and 22.2.0.dev0 (commit b1a681a)
- Python version: 3.8.13
- Operating System: Debian bullseye
The following code:
from __future__ import annotations
from dataclasses import dataclass
import cattrs
@dataclass
class Foo:
items: list[str]
print(cattrs.structure({"items": ["red", "green", "blue"]}, Foo))succeeds on Python 3.9 but fails on 3.8 with the following traceback:
Traceback (most recent call last):
File "listitems01.py", line 9, in <module>
print(cattrs.structure({"items": ["red", "green", "blue"]}, Foo))
File "/docked/venv/lib/python3.8/site-packages/cattrs/converters.py", line 283, in structure
return self._structure_func.dispatch(cl)(obj, cl)
File "/docked/venv/lib/python3.8/site-packages/cattrs/dispatch.py", line 49, in _dispatch
return self._function_dispatch.dispatch(cl)
File "/docked/venv/lib/python3.8/site-packages/cattrs/dispatch.py", line 122, in dispatch
return handler(typ)
File "/docked/venv/lib/python3.8/site-packages/cattrs/converters.py", line 780, in gen_structure_attrs_fromdict
h = make_dict_structure_fn(
File "/docked/venv/lib/python3.8/site-packages/cattrs/gen.py", line 265, in make_dict_structure_fn
attrs = adapted_fields(cl)
File "/docked/venv/lib/python3.8/site-packages/cattrs/_compat.py", line 74, in adapted_fields
type_hints = get_type_hints(cl)
File "/usr/local/lib/python3.8/typing.py", line 1232, in get_type_hints
value = _eval_type(value, base_globals, localns)
File "/usr/local/lib/python3.8/typing.py", line 270, in _eval_type
return t._evaluate(globalns, localns)
File "/usr/local/lib/python3.8/typing.py", line 518, in _evaluate
eval(self.__forward_code__, globalns, localns),
File "<string>", line 1, in <module>
TypeError: 'type' object is not subscriptable