Crash with dataclass enums

[Gunni]

Bug description

When parsing the following a.py:

from dataclasses import dataclass
from enum import Enum


@dataclass
class Something(str, Enum):
	asd: str = 'sdf'

Configuration

No response

Command used

pylint a.py

Pylint output

<details open>
    <summary>
        pylint crashed with a ``AstroidError`` and with the following stacktrace:
    </summary>


Traceback (most recent call last):
  File "/somewhere/test_pylint_enum/.venv/lib64/python3.11/site-packages/pylint/lint/pylinter.py", line 788, in _lint_file
    check_astroid_module(module)
  File "/somewhere/test_pylint_enum/.venv/lib64/python3.11/site-packages/pylint/lint/pylinter.py", line 1017, in check_astroid_module
    retval = self._check_astroid_module(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/somewhere/test_pylint_enum/.venv/lib64/python3.11/site-packages/pylint/lint/pylinter.py", line 1069, in _check_astroid_module
    walker.walk(node)
  File "/somewhere/test_pylint_enum/.venv/lib64/python3.11/site-packages/pylint/utils/ast_walker.py", line 94, in walk
    self.walk(child)
  File "/somewhere/test_pylint_enum/.venv/lib64/python3.11/site-packages/pylint/utils/ast_walker.py", line 94, in walk
    self.walk(child)
  File "/somewhere/test_pylint_enum/.venv/lib64/python3.11/site-packages/pylint/utils/ast_walker.py", line 94, in walk
    self.walk(child)
  File "/somewhere/test_pylint_enum/.venv/lib64/python3.11/site-packages/pylint/utils/ast_walker.py", line 91, in walk
    callback(astroid)
  File "/somewhere/test_pylint_enum/.venv/lib64/python3.11/site-packages/pylint/checkers/base/name_checker/checker.py", line 488, in visit_assignname
    if utils.is_enum_member(node) or utils.is_assign_name_annotated_with(
       ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/somewhere/test_pylint_enum/.venv/lib64/python3.11/site-packages/pylint/checkers/utils.py", line 2284, in is_enum_member
    enum_member_objects = frame.locals.get("__members__")[0].items
                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^
TypeError: 'NoneType' object is not subscriptable

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/somewhere/test_pylint_enum/.venv/lib64/python3.11/site-packages/pylint/lint/pylinter.py", line 752, in _lint_files
    self._lint_file(fileitem, module, check_astroid_module)
  File "/somewhere/test_pylint_enum/.venv/lib64/python3.11/site-packages/pylint/lint/pylinter.py", line 790, in _lint_file
    raise astroid.AstroidError from e
astroid.exceptions.AstroidError




</details>

Expected behavior

No crash. Works on 2.17.7.

Pylint version

pylint 3.0.0
astroid 3.0.0
Python 3.11.5 (main, Aug 28 2023, 00:00:00) [GCC 13.2.1 20230728 (Red Hat 13.2.1-1)]

OS / Environment

NAME="Fedora Linux"
VERSION="38 (Workstation Edition)"

Additional dependencies

No response

[mbyrnepr2]

Thanks Gunni for the catch!
@Pierre-Sassoulas our handling of data classes seems to interfere in this situation because the __members__ object is not present anymore. It doesn't happen when other decorators are used instead of dataclass.

So, as a way forward, how about we catch the TypeError for this scenario in pylint and independently create an issue in astroid to be able to understand dataclass + enum classes?

[Pierre-Sassoulas]

I think it depends on the difficulty of the fix in astroid. If it's very hard then sure let's prevent the crash temporarily in pylint with a try/except.