subprocess.check_output() accept the check keyword argument

[remilapeyre]

BPO	40497
Nosy	@tiran, @ambv, @remilapeyre
PRs	bpo-40497: Fix handling of check in subprocess.check_output() #19897

^{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 2021-09-20.15:09:53.160>
created_at = <Date 2020-05-04.09:54:48.850>
labels = ['type-bug', 'library', '3.11']
title = 'subprocess.check_output() accept the check keyword argument'
updated_at = <Date 2021-09-20.15:09:53.158>
user = 'https://github.com/remilapeyre'

bugs.python.org fields:

activity = <Date 2021-09-20.15:09:53.158>
actor = 'lukasz.langa'
assignee = 'none'
closed = True
closed_date = <Date 2021-09-20.15:09:53.160>
closer = 'lukasz.langa'
components = ['Library (Lib)']
creation = <Date 2020-05-04.09:54:48.850>
creator = 'remi.lapeyre'
dependencies = []
files = []
hgrepos = []
issue_num = 40497
keywords = ['patch']
message_count = 7.0
messages = ['368027', '368029', '368031', '368032', '368035', '402239', '402240']
nosy_count = 3.0
nosy_names = ['christian.heimes', 'lukasz.langa', 'remi.lapeyre']
pr_nums = ['19897']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue40497'
versions = ['Python 3.11']

[remilapeyre]

The subprocess.check_output() raises TypeError when given the check keyword-argument:

Python 3.8.2 (v3.8.2:7b3ab5921f, Feb 24 2020, 17:52:18) 
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import subprocess
>>> subprocess.check_output(['ls'], check=False)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/subprocess.py", line 411, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
TypeError: run() got multiple values for keyword argument 'check'

It should just use True as the default when it's not specified in kwargs.

[tiran]

-1

check_output() should not accept check=False. Please only improve the error message. I would be fine with accepting check=True, too

[remilapeyre]

check_output() should not accept check=False.

I thought about raising ValueError instead but subprocess.check_output([...], check=False) is actually a convenient shortcut over subprocess.run([...], stdout=subprocess.PIPE).stdout and I can't think of much drawbacks if someone explicitly ask for the check to be disabled. Is there any way we could have that?

[tiran]

IMHO it's both confusing and bad API design to have a function like

    validate_result(..., validate=False)

Now a reviewer has to check that a developer uses the validate_result() function *and* the developer is not passing validate=False into the function.

#64096 is also provides a new feature, so it cannot get into Python 3.7 and 3.8.

[remilapeyre]

Now a reviewer has to check that a developer uses the validate_result() function *and* the developer is not passing validate=False into the function.

Fair enough, I updated the PR to raise ValueError instead.

[ambv]

New changeset 4d2957c by Rémi Lapeyre in branch 'main':
bpo-40497: Fix handling of check in subprocess.check_output() (GH-19897)
4d2957c

[ambv]

Fixed with #64096 for Python 3.11. Thanks! ✨ 🍰 ✨