GeezerVison is showing github.com — io.TextIOBase.buffer is not necessarily a buffer · Issue #85045 · python/cpython

io.TextIOBase.buffer is not necessarily a buffer #85045

New issue

Copy link

New issue

Copy link

Closed

io.TextIOBase.buffer is not necessarily a buffer#85045

Copy link

Labels

docsDocumentation in the Doc dirDocumentation in the Doc dirtopic-IO

Description

manueljacob

mannequin

opened

on Jun 5, 2020

Issue body actions

BPO	40868
Nosy	@manueljacob

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

Show more details

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-06-05.01:15:31.315>
labels = ['expert-IO', 'docs']
title = 'io.TextIOBase.buffer is not necessarily a buffer'
updated_at = <Date 2020-06-05.01:15:31.315>
user = 'https://github.com/manueljacob'

bugs.python.org fields:

activity = <Date 2020-06-05.01:15:31.315>
actor = 'mjacob'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation', 'IO']
creation = <Date 2020-06-05.01:15:31.315>
creator = 'mjacob'
dependencies = []
files = []
hgrepos = []
issue_num = 40868
keywords = []
message_count = 1.0
messages = ['370744']
nosy_count = 2.0
nosy_names = ['docs@python', 'mjacob']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue40868'
versions = []

Linked PRs

Reacted by Shahriar Heidrich

Activity

manueljacob commented on Jun 5, 2020
manueljacobmannequin
on Jun 5, 2020
MannequinAuthor
More actions
https://docs.python.org/dev/library/io.html#io.TextIOBase.buffer says:

"The underlying binary buffer (a BufferedIOBase instance) that TextIOBase deals with. This is not part of the TextIOBase API and may not exist in some implementations."

It is not necessarily a buffer (a BufferedIOBase instance), e.g. when the stdout and stderr streams are set to be unbuffered. Example:

% python -u Python 3.8.3 (default, May 17 2020, 18:15:42) [GCC 10.1.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import io, sys >>> sys.stdout <_io.TextIOWrapper name='<stdout>' mode='w' encoding='utf-8'> >>> isinstance(sys.stdout, io.TextIOBase) True >>> sys.stdout.buffer <_io.FileIO name='<stdout>' mode='wb' closefd=False> >>> isinstance(sys.stdout.buffer, io.BufferedIOBase) False

Therefore the name and the documentation are incorrect.

I suggest to deprecate the attribute "buffer", introduce a new attribute with a correct name, and forward the old attribute to the new attribute and vice versa in the io.TextIOBase class.

I think that "binary" would be a good attribute name for the underlying binary stream, as it would be consistent with io.BufferedIOBase.raw (for "the underlying raw stream").
manueljacob
assigned
docspython
on Jun 5, 2020
manueljacob
added
docsDocumentation in the Doc dirDocumentation in the Doc dir

topic-IO
on Jun 5, 2020
manueljacob
assigned
docspython
on Jun 5, 2020
manueljacob
added
docsDocumentation in the Doc dirDocumentation in the Doc dir

topic-IO
on Jun 5, 2020
ezio-melotti
transferred this issue from on Apr 10, 2022
AlexKautz commented on May 20, 2025
AlexKautz
on May 20, 2025
More actions
I'll grab this.
[Hello from PyCon Sprints]
Focus on just updating the documentation rather than introducing any breaking changes.
Reacted by Shahriar Heidrich
Reacted by Shahriar Heidrich
Reacted by Shahriar Heidrich
gpshead
added a commit that references this issue on May 20, 2025
gh-85045: clarified that the underlying buffer of a TextIOBase can be…
36eb711
miss-islington
added 2 commits that reference this issue on May 20, 2025
pythongh-85045: clarified that the underlying buffer of a TextIOBase …
d495021
pythongh-85045: clarified that the underlying buffer of a TextIOBase …
5a6c3dc
gpshead
added 2 commits that reference this issue on May 20, 2025
[3.14] gh-85045: clarified that the underlying buffer of a TextIOBase…
899ce7d
[3.13] gh-85045: clarified that the underlying buffer of a TextIOBase…
7df6749
gpshead commented on May 20, 2025
gpshead
on May 20, 2025
Member
More actions
thanks!
gpshead
closed this as completed on May 20, 2025
lkollar
added a commit that references this issue on May 26, 2025
pythongh-85045: clarified that the underlying buffer of a TextIOBase …
2170fab
Pranjal095
added a commit that references this issue on Jul 12, 2025
pythongh-85045: clarified that the underlying buffer of a TextIOBase …
85c2bd6
taegyunkim
added a commit that references this issue on Aug 4, 2025
pythongh-85045: clarified that the underlying buffer of a TextIOBase …
02cc7bc