__bases__ is a tuple (possibly empty or a singleton)

[DimitrisJim]

BPO	29012
Nosy	@bitdancer, @berkerpeksag, @serhiy-storchaka, @DimitrisJim
Files	fixbasesdoc.patch fixbasesdoc2.patch

^{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 = None
closed_at = <Date 2017-01-02.02:59:48.874>
created_at = <Date 2016-12-19.08:00:07.600>
labels = ['type-bug', '3.7', 'docs']
title = '__bases__ is a tuple (possibly empty or a singleton)'
updated_at = <Date 2017-01-03.00:35:28.886>
user = 'https://github.com/DimitrisJim'

bugs.python.org fields:

activity = <Date 2017-01-03.00:35:28.886>
actor = 'berker.peksag'
assignee = 'docs@python'
closed = True
closed_date = <Date 2017-01-02.02:59:48.874>
closer = 'berker.peksag'
components = ['Documentation']
creation = <Date 2016-12-19.08:00:07.600>
creator = 'Jim Fasarakis-Hilliard'
dependencies = []
files = ['45962', '46117']
hgrepos = []
issue_num = 29012
keywords = ['patch']
message_count = 8.0
messages = ['283595', '283609', '284446', '284447', '284470', '284510', '284512', '284513']
nosy_count = 6.0
nosy_names = ['r.david.murray', 'docs@python', 'python-dev', 'berker.peksag', 'serhiy.storchaka', 'Jim Fasarakis-Hilliard']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue29012'
versions = ['Python 3.5', 'Python 3.6', 'Python 3.7']

[DimitrisJim]

The following statement is in the Language Reference for Custom classes:

__bases__ is a tuple (possibly empty or a singleton) containing the base classes

AFAIK, object.__bases__ is the only object for which __bases__ is empty and it isn't a custom class. Attempts to create a class and assign bases to an empty tuple is checked to enforce inheritance from object. This seems to be something that slipped through when the docs were created for Python 3.0?

I'm curious to see if this can actually be empty, if not, attached patch removes ''empty'' from the sentence.

[bitdancer]

Most likely it just slipped through. In 2.7 the section is just called 'classes', not 'custom classes', and covered both classic classes and the new style classes that are all that python3 has.

[python-dev]

New changeset 721df314d45a by Berker Peksag in branch '3.5':
Issue bpo-29012: Remove outdated information about __bases__
https://hg.python.org/cpython/rev/721df314d45a

New changeset 019125fb6d66 by Berker Peksag in branch '3.6':
Issue bpo-29012: Merge from 3.5
https://hg.python.org/cpython/rev/019125fb6d66

New changeset 454426dbff83 by Berker Peksag in branch 'default':
Issue bpo-29012: Merge from 3.6
https://hg.python.org/cpython/rev/454426dbff83

[berkerpeksag]

Thanks, Jim.

[serhiy-storchaka]

I think "possible a singleton" can be removed too. It doesn't add any useful information, any tuple is possible a singleton.

[DimitrisJim]

Yes, I agree with that it seems redundant after the change. I'm attaching another small patch based on the committed one to trim that off.

[python-dev]

New changeset 1aba7cbbcc27 by Berker Peksag in branch '3.5':
Issue bpo-29012: Remove another outdated information
https://hg.python.org/cpython/rev/1aba7cbbcc27

New changeset 7ef5b02b228a by Berker Peksag in branch '3.6':
Issue bpo-29012: Merge from 3.5
https://hg.python.org/cpython/rev/7ef5b02b228a

New changeset f05165a9cae6 by Berker Peksag in branch 'default':
Issue bpo-29012: Merge from 3.6
https://hg.python.org/cpython/rev/f05165a9cae6

[berkerpeksag]

Good point, Serhiy. Thanks for the patch, Jim. I've now removed the "possible a singleton" part.