[New-bugs-announce] [issue34122] inspect.getmembers does not retrive dataclass's __dataclass_fields__ properly

[Dong-hee Na]

New submission from Dong-hee Na <donghee.na92 at gmail.com>:

When I execute this script.

import inspect
from dataclasses import *
import enum

@dataclass
class SimpleDataObject(object):
    field_a: int = field()
    field_b: str = "asdad"

print([a[0] for a in inspect.getmembers(SimpleDataObject)])


I expected

['__annotations__', '__class__', '__dataclass_fields__', '__dataclass_params__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'field_a', 'field_b']

but got

['__annotations__', '__class__', '__dataclass_fields__', '__dataclass_params__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'field_b']

If this behavior is not intended, I propose a new patch with providing Inspect.isdataclass for Python 3.8 and Inspect._is_dataclss for Python 3.7

https://github.com/corona10/cpython/commit/c2665176ce836a7b328ddc09c6c7d3de0a2b29a0

----------
components: Library (Lib)
files: inspect_dataclass.py
messages: 321706
nosy: corona10, eric.smith, serhiy.storchaka, yselivanov
priority: normal
severity: normal
status: open
title: inspect.getmembers does not retrive dataclass's __dataclass_fields__ properly
versions: Python 3.7, Python 3.8
Added file: https://bugs.python.org/file47693/inspect_dataclass.py

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue34122>
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