False positives `invalid-enum-extension`

[Bibo-Joshi]

Bug description

That check doesn't seem to check if the parent class actually defines enumeration members. This happens only if the parent class is defined in a differen module. MWE:

bar.py

import Enum

class StringEnum(str, Enum):
    def __repr__(self) -> str:
        return f"<{self.__class__.__name__}.{self.name}>"

foo.py

from bar import StringEnum


class ChatType(StringEnum):

    SENDER = "sender"
    PRIVATE = "private"

Configuration

No response

Command used

`pylint foo.py`

Pylint output

************* Module foo
foo.py:1:0: C0114: Missing module docstring (missing-module-docstring)
foo.py:1:0: C0104: Disallowed name "foo" (disallowed-name)
foo.py:4:0: E0244: Extending inherited Enum class "StringEnum" (invalid-enum-extension)

------------------------------------------------------------------
Your code has been rated at 0.00/10 (previous run: 0.00/10, +0.00)

Expected behavior

pylint either checks the parent class for enum members or does enable this warning by default

Pylint version

pylint 2.14.1
astroid 2.11.5
Python 3.8.5

OS / Environment

Windows

Additional dependencies

No response

[DanielNoord]

I can't reproduce this locally:

❯ cat bar.py
from enum import Enum


class StringEnum(str, Enum):
    def __repr__(self) -> str:
        return f"<{self.__class__.__name__}.{self.name}>"
❯ cat foo.py
from bar import StringEnum


class ChatType(StringEnum):

    SENDER = "sender"
    PRIVATE = "private"
❯ pylint --version
pylint 2.14.1
astroid 2.11.5
Python 3.10.0 (default, Oct 27 2021, 16:20:25) [Clang 13.0.0 (clang-1300.0.29.3)]
❯ pylint --enable=invalid-enum-extension foo.py
************* Module foo
foo.py:1:0: C0114: Missing module docstring (missing-module-docstring)
foo.py:1:0: C0104: Disallowed name "foo" (disallowed-name)
foo.py:4:0: C0115: Missing class docstring (missing-class-docstring)

------------------------------------------------------------------
Your code has been rated at 2.50/10 (previous run: 2.50/10, +0.00)

[Bibo-Joshi]

Thanks for the reply! I did some more testing and apparently I missed something while putting together the first MWE. My apologies for that. I now think that a __slots__ entry in the parent is the problem, maybe because it's interpreted as enum member.

New MWE:

> cat .\foo.py
"""module"""
from enum import Enum


class StringEnum(str, Enum):
    __slots__ = ("a", "b")


class ChatType(StringEnum):

    SENDER = "sender"
    PRIVATE = "private"
> pylint --version
pylint 2.14.1
astroid 2.11.5
Python 3.10.4 (tags/v3.10.4:9d38120, Mar 23 2022, 23:13:41) [MSC v.1929 64 bit (AMD64)]
> pylint foo.py
************* Module foo
foo.py:1:0: C0104: Disallowed name "foo" (disallowed-name)
foo.py:5:0: C0115: Missing class docstring (missing-class-docstring)
foo.py:9:0: C0115: Missing class docstring (missing-class-docstring)
foo.py:9:0: E0244: Extending inherited Enum class "StringEnum" (invalid-enum-extension)

------------------------------------------------------------------
Your code has been rated at 0.00/10 (previous run: 0.00/10, +0.00)

[Bibo-Joshi]

The discussion in #7257 lead to pylint-dev/astroid#1730. I leave it up to the maintainers to decide whether to keep this issue open.

[PabloAlexis611]

Hello there!

I also experience this issue when using django-enumfield.

For example:

from django_enumfield import enum

class Animals(enum.Enum):
  CAT = 1
  DOG = 2
  SHARK = 3
  
  __labels__ = {
    CAT: "Cat",
    DOG: "Dog",
    SHARK: "SHARK!!!",
  }

I then get the following pylint error: pylint: invalid-enum-extension / Extending inherited Enum class "Enum"