False positive no-member for subclass of enum.Enum

[pylint-bot]

Originally reported by: BitBucket: iceout, GitHub: @iceout?

---

Python-2.7.6 + enum34 (Enum backported from Python-3.4.0)

test code:

# pylint: disable=missing-docstring, invalid-name


from enum import Enum


class OrderedEnum(Enum):

    def __ge__(self, other):
        if self.__class__ is other.__class__:
            return self.value >= other.value  # line 11
        return NotImplemented

    def __gt__(self, other):
        if self.__class__ is other.__class__:
            return self.value > other.value  # line 16
        return NotImplemented


class Color(OrderedEnum):
    red = 0
    green = 1


class People(Enum):
    jack = 0
    john = 1


print(Color.red.value)  # line 29
print(People.jack.name)

pylint -E test.py:

E: 11,19: Instance of 'OrderedEnum' has no 'value' member (no-member)
E: 16,19: Instance of 'OrderedEnum' has no 'value' member (no-member)
E: 29, 6: Instance of 'int' has no 'value' member (no-member)

---

• Bitbucket: https://bitbucket.org/logilab/pylint/issue/533

[pylint-bot]

Original comment by Claudiu Popa (BitBucket: PCManticore, GitHub: @PCManticore):

---

Yes, this was intentional (handling subclasses for enums was a little complicated when support for them was added). This should be fixed in astroid at some point, here's the relevant code: https://bitbucket.org/logilab/astroid/src/f75482328c8c39538c74fa9a85915ec5c58ce1fa/astroid/brain/py2stdlib.py?at=default#cl-281

[xvjiarui]

have the same problem.

import inspect
from enum import Enum

class ChoiceEnum(Enum):

	@classmethod
	def choices(cls):
		# get all members of the class
		members = inspect.getmembers(cls, lambda m: not(inspect.isroutine(m)))
		# filter down to just properties
		props = [m for m in members if not(m[0][:2] == '__')]
		# format into django choice tuple
		choices = tuple([(p[1].value, p[0]) for p in props])
		return choices

class BookingState(ChoiceEnum):
	IS_BOOKING = 0
	CONFIRMED = 1
	PAID = 2

class TourOfferingState(ChoiceEnum):
	OPEN = 0
	CONFIRMED = 1
	CANCELED = 2
	CLOSED = 3 

[LJBD]

Is there anything that can be done in this issue?
I've got the same problem subclassing IntEnum in Python 3.6.

[PCManticore]

@LJBD Apart of disabling the check for now, no, there's no other solution. It would be great to have this fixed, but can't promise exactly when that's going to happen, unless someone proposes a patch to speed this up.

[mplanchard]

FYI a partial workaround here is to define your enum overrides as a mixin, and then subclass enum explicitly in all of your "subclasses." For example:

from enum import Enum

class SpecialEnumMixin:
  def __new__(cls, value, info):
    obj = object.__new__(cls)
    obj._value_ = value
    obj._info = info
    return obj

  @property
  def info(self):
    return self._info

class SpecialEnum(SpecialEnumMixin, Enum):
  A = ("a", "this is a")
  B = ("b", "this is b")

assert SpecialEnum.A.info == "this is a"
assert SpecialEnum("a") is SpecialEnum.A

Doing it this way, pylint recognizes the "subclass" correctly as an enum.

[dufferzafar]

Is there a way to disable such no-member violations? Without disabling ALL of them?

[gbrennon]

Why people didn't fix this?

[mplanchard]

@gbrennon looks like they're willing to accept patches if you can find the cause of the issue and fix it yourself

[manimathma]

Is there a way to disable such no-member violations? Without disabling ALL of them?

@dufferzafar : this might help https://pylint.readthedocs.io/en/latest/user_guide/message-control.html

[Pierre-Sassoulas]

In pylint 2.8 the result is now:

************* Module functional.e.enum_subclass
enum_subclass.py:13:19: W0143: Comparing against a callable, did you omit the parenthesis? (comparison-with-callable)
enum_subclass.py:18:19: W0143: Comparing against a callable, did you omit the parenthesis? (comparison-with-callable)
enum_subclass.py:32:6: E1101: Instance of 'int' has no 'value' member (no-member)

So it's still an issue. The relevant code seems to be here: https://github.com/PyCQA/astroid/blob/master/astroid/brain/brain_namedtuple_enum.py

[OldIMP]

Hi @Pierre-Sassoulas:

I still get the false positive E1101 for self defined members.

Example:

• Enum Layout w/ self defined members col & row
• Here will then be reported falsely as E1101:

  r_quiz.py:174:12: E1101: Instance of 'SIMPLE' has no 'row' member (no-member)
  r_quiz.py:174:12: E1101: Instance of 'SCHRIFTLICH' has no 'row' member (no-member)
  r_quiz.py:174:25: E1101: Instance of 'SIMPLE' has no 'col' member (no-member)
  r_quiz.py:174:25: E1101: Instance of 'SCHRIFTLICH' has no 'col' member (no-member)

pylint --version

pylint 2.11.1
astroid 2.8.2
Python 3.9.7 | packaged by conda-forge | (default, Sep 29 2021, 19:15:42) [MSC v.1916 64 bit (AMD64)]

Should I create a new issue for it?

[Pierre-Sassoulas]

That syntax is very handy, I did not know it worked. Could you open a new issue, please ?

[OldIMP]

❤ #5138 created

[bluefish6]

Hi @Pierre-Sassoulas, I see the same behaviour when I'm importing enum.Enum with a different name (to prevent confusion when also doing from sqlalchemy.dialects.postgresql import ENUM):

from enum import Enum as PyEnum


class MyEnum(PyEnum):
    ENUM_KEY = "enum_value"


foo = MyEnum.ENUM_KEY.value

pylint example.py 
************* Module example
example.py:8:6: E1101: Instance of 'str' has no 'value' member (no-member)

The error goes away when Enum is imported without renaming to PyEnum

$ pylint --version

pylint 2.12.2
astroid 2.9.3
Python 3.8.10 (default, Nov 26 2021, 20:14:08) 
[GCC 9.3.0]

Should I open a new issue or this one can be reopened?

[Pierre-Sassoulas]

Thank you for the report, could you open a new issue, please ? :)

[bluefish6]

Thank you for the report, could you open a new issue, please ? :)

Opened #5776, thanks! :)