__base__ undocumented

[Arfrever]

BPO	22456
Nosy	@gvanrossum, @rhettinger
Files	function-documentation.patch: Patch containing documentation of base

^{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 = None
created_at = <Date 2014-09-21.22:54:27.151>
labels = ['easy', 'type-feature', 'docs']
title = '__base__ undocumented'
updated_at = <Date 2014-09-30.12:59:10.672>
user = 'https://bugs.python.org/Arfrever'

bugs.python.org fields:

activity = <Date 2014-09-30.12:59:10.672>
actor = 'anupama.srinivas.murthy'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2014-09-21.22:54:27.151>
creator = 'Arfrever'
dependencies = []
files = ['36760']
hgrepos = []
issue_num = 22456
keywords = ['patch', 'easy']
message_count = 5.0
messages = ['227241', '227242', '227243', '227245', '227903']
nosy_count = 5.0
nosy_names = ['gvanrossum', 'rhettinger', 'Arfrever', 'docs@python', 'anupama.srinivas.murthy']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue22456'
versions = ['Python 2.7', 'Python 3.4', 'Python 3.5']

Linked PRs

• gh-66646: Explain __base__ attribute in the docs #102554
• [3.14] gh-66646: Explain __base__ attribute in the docs (GH-102554) #140365
• [3.13] gh-66646: Explain __base__ attribute in the docs (GH-102554) #140366

[Arfrever]

__bases__ is documented, but __base__ is not.

$ grep -r __base__ Doc
$ grep -r __bases__ Doc
Doc/c-api/object.rst:are different objects, *B*'s :attr:`~class.__bases__` attribute is searched in
Doc/c-api/object.rst:a depth-first fashion for *A* --- the presence of the :attr:`~class.__bases__`
Doc/extending/newtypes.rst:   in its :attr:`~class.__bases__`, or else it will not be able to call your type's
Doc/library/email.headerregistry.rst:    class's ``__bases__`` list.
Doc/library/functions.rst:   tuple itemizes the base classes and becomes the :attr:`~class.__bases__`
Doc/library/stdtypes.rst:.. attribute:: class.__bases__
Doc/reference/datamodel.rst:      single: __bases__ (class attribute)
Doc/reference/datamodel.rst:   dictionary containing the class's namespace; :attr:`~class.__bases__` is a
Doc/whatsnew/2.3.rst:  removed: you can now assign to the :attr:`__name__` and :attr:`__bases__`
Doc/whatsnew/2.3.rst:  assigned to :attr:`__bases__` along the lines of those relating to assigning to

[rhettinger]

I think that __base__ was intended to be a non-guaranteed implementation detail for new-style classes just like __dictoffset__ and __flags__ .

[gvanrossum]

Raymond is correct. __base__ is closely tied to the C implementation. I think it might be worth a mention, but with an explicit note that it is CPython-specific. It is sometimes useful, e.g. when wondering why a certain case of multiple inheritance is rejected.

[Arfrever]

__base__ exists also in Jython and PyPy.

[anupamasrinivasmurthy]

I have documented the function in object.rst file. I do not know the use of the function and have not mentioned that. My documentation is based on what I understood from the comments below and the explanation here:
http://code.activestate.com/lists/python-list/334282/

[furkanonder]

__bases__ is an undocumented feature. I believe it is worth mentioning in the object.rst , stdtypes.rst and datamodel.rst documents.

[merwok]

It’s an undocumented implementation detail, not a language feature.