asdict() on dataclass with defaultdict raises TypeError: "first argument must be callable or None " #106113
Closed as not planned
Description
Bug report
Minimal working example:
from dataclasses import dataclass, field, asdict
from typing import DefaultDict
from collections import defaultdict
def default_list_dict():
return defaultdict(list)
@dataclass
class Data:
metadata: DefaultDict = field(default_factory=default_list_dict)
D = Data() # => Data(metadata=defaultdict(<class 'list'>, {}))
asdict(D)- Expected output:
{'metadata': defaultdict(list, {})} - Got instead:
TypeError: first argument must be callable or None
Display traceback
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
Cell In[1], line 13
10 metadata: DefaultDict = field(default_factory=default_list_dict)
12 D = Data()
---> 13 asdict(D)
File ~/miniconda3/lib/python3.10/dataclasses.py:1238, in asdict(obj, dict_factory)
1236 if not _is_dataclass_instance(obj):
1237 raise TypeError("asdict() should be called on dataclass instances")
-> 1238 return _asdict_inner(obj, dict_factory)
File ~/miniconda3/lib/python3.10/dataclasses.py:1245, in _asdict_inner(obj, dict_factory)
1243 result = []
1244 for f in fields(obj):
-> 1245 value = _asdict_inner(getattr(obj, f.name), dict_factory)
1246 result.append((f.name, value))
1247 return dict_factory(result)
File ~/miniconda3/lib/python3.10/dataclasses.py:1275, in _asdict_inner(obj, dict_factory)
1273 return type(obj)(_asdict_inner(v, dict_factory) for v in obj)
1274 elif isinstance(obj, dict):
-> 1275 return type(obj)((_asdict_inner(k, dict_factory),
1276 _asdict_inner(v, dict_factory))
1277 for k, v in obj.items())
1278 else:
1279 return copy.deepcopy(obj)
TypeError: first argument must be callable or NoneYour environment
- CPython versions tested on: Python 3.10.11 [GCC 11.2.0] on linux
- Operating system and architecture: Linux 6.1.31-2-MANJARO Support "bpo-" in Misc/NEWS #1 SMP PREEMPT_DYNAMIC Sun Jun 4 12:31:46 UTC 2023 x86_64 GNU/Linux