Enum's dir() does not contain inherited members

@warsaw

BPO	45535
Nosy	@warsaw, @ethanfurman, @serhiy-storchaka, @AlexWaygood
PRs	bpo-45535: Improve output of Enum `dir()` #29316 bpo-45535: [Enum] include special dunders in dir() #30677
Superseder	bpo-40066: Enum: modify repr, str; update docs
Files	Enum_dir_patch.txt enum_dir_output_with_patch.txt

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/ethanfurman'
closed_at = <Date 2022-01-17.17:02:11.779>
created_at = <Date 2021-10-20.10:35:06.095>
labels = ['type-bug', 'library', '3.10', '3.11']
title = "Enum's dir() does not contain inherited members"
updated_at = <Date 2022-01-18.23:13:23.710>
user = 'https://github.com/serhiy-storchaka'

bugs.python.org fields:

activity = <Date 2022-01-18.23:13:23.710>
actor = 'ethan.furman'
assignee = 'ethan.furman'
closed = True
closed_date = <Date 2022-01-17.17:02:11.779>
closer = 'ethan.furman'
components = ['Library (Lib)']
creation = <Date 2021-10-20.10:35:06.095>
creator = 'serhiy.storchaka'
dependencies = []
files = ['50382', '50383']
hgrepos = []
issue_num = 45535
keywords = ['patch']
message_count = 11.0
messages = ['404420', '404621', '404634', '404635', '404721', '405313', '405320', '405323', '407539', '410807', '410912']
nosy_count = 5.0
nosy_names = ['barry', 'eli.bendersky', 'ethan.furman', 'serhiy.storchaka', 'AlexWaygood']
pr_nums = ['29316', '30677']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = '40066'
type = 'behavior'
url = 'https://bugs.python.org/issue45535'
versions = ['Python 3.10', 'Python 3.11']

For example:

>>> from enum import *
>>> class E(IntEnum):
...     x = 1
... 
>>> dir(E)
['__class__', '__doc__', '__members__', '__module__', 'x']
>>> E.from_bytes
<built-in method from_bytes of EnumType object at 0x559d47415ce0>
>>> E.to_bytes
<method 'to_bytes' of 'int' objects>
>>> E.numerator
<attribute 'numerator' of 'int' objects>
>>> E.__add__
<slot wrapper '__add__' of 'int' objects>

There are methods and attributes inherited from int, but they are not shown in dir(). As result they are absent in help() and completion does not work for them.

I had a go at writing a patch for __dir__ that would include any methods an enum class had acquired through int/str/etc. mixins, while continuing to ignore enum dunders and sunders (as is currently the case). My patch also allows user-defined methods defined in enum subclasses to show up in the help() output, whereas they currently do not, since help(enum_member) looks up dir(enum_class) rather than dir(enum_member).

The patch is a fair way more complex than the the existing code, however.

Looks interesting, thank you for the patch.

There may be a simple error (superfluous .__class__), but I am not sure.

BTW, why use mro() instead of __mro__? Most code use __mro__.

Would there be interest in me submitting a PR along these lines?

----

why use mro() instead of __mro__?

Er, no reason, really. To be honest, I've never really understood why Python has both.

PR 29316 looks complicated.

First of all, why do Enum needs a custom __dir__? What is wrong with the default implementation?

Enums have had a custom dir() from the beginning, partly because they are not standard objects and do not follow standard rules.

The question posed by this issue is whether Enums with mixed-in data types should show the inherited methods, and if yes, should it also show inherited __dunders__.

I'm inclined to say yes for the normal inherited methods, I'm not sure about inherited __dunders__.

I would argue it's quite important for IntEnum to have the dunder methods inherited from int show up in help(). Dunder methods indicate that an object has certain behaviours, so it's important for a user to be able to verify that an IntEnum member has similar behaviours to an int instance. IntEnum is advertised in the documentation as something that can be used everywhere where an integer is expected; it's surprising when the output from help() is hugely abbreviated for IntEnum relative to int.

But, I agree that my first draft of this PR is more complex than I'd like it to be.

New changeset b2afdc9 by Alex Waygood in branch 'main':
bpo-45535: Improve output of Enum dir() (GH-29316)
b2afdc9

Fixed in 3.11.

Pure enums have a few more dir() entries now; mixed enums now show all inherited methods/attributes -- members still do not show up in member dirs (this is a good thing).

New changeset 7c0914d by Ethan Furman in branch 'main':
bpo-45535: [Enum] include special dunders in dir() (GH-30677)
7c0914d

@ethanfurman

@ethanfurman: test_enum.test_dir_with_custom_dunders() is skipped since 2022, since commit 7c0914d:

commit 7c0914d35eaaab2f323260ba5fe8884732533888
Author: Ethan Furman <ethan@stoneleaf.us>
Date:   Tue Jan 18 15:13:13 2022 -0800

    bpo-45535: [Enum] include special dunders in dir() (GH-30677)
    
    Include the `__dunders__` in `dir()` that make `Enum` special:
    
    - `__contains__`
    - `__getitem__`
    - `__iter__`
    - `__len__`
    - `__members__`

What's the status of this test? Should it be removed?

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Enum's dir() does not contain inherited members #89698

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Enum's dir() does not contain inherited members #89698

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serhiy-storchaka commented on Oct 20, 2021

AlexWaygood commented on Oct 21, 2021

ethanfurman commented on Oct 21, 2021

serhiy-storchaka commented on Oct 21, 2021

AlexWaygood commented on Oct 22, 2021

serhiy-storchaka commented on Oct 29, 2021

ethanfurman commented on Oct 29, 2021

AlexWaygood commented on Oct 29, 2021

ethanfurman commented on Dec 2, 2021

ethanfurman commented on Jan 17, 2022

ethanfurman commented on Jan 18, 2022

vstinner commented on Oct 2, 2025

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