Description

assignee = None
closed_at = <Date 2020-06-06.02:31:45.829>
created_at = <Date 2020-06-04.11:59:48.464>
labels = ['library', '3.9', '3.10']
title = 'argparse.BooleanOptionalAction accept and silently discard its the const argument'
updated_at = <Date 2020-06-07.16:22:59.941>
user = 'https://github.com/remilapeyre'

activity = <Date 2020-06-07.16:22:59.941>
actor = 'paul.j3'
assignee = 'none'
closed = True
closed_date = <Date 2020-06-06.02:31:45.829>
closer = 'rhettinger'
components = ['Library (Lib)']
creation = <Date 2020-06-04.11:59:48.464>
creator = 'remi.lapeyre'
dependencies = []
files = []
hgrepos = []
issue_num = 40862
keywords = ['patch']
message_count = 6.0
messages = ['370703', '370772', '370776', '370777', '370792', '370811']
nosy_count = 4.0
nosy_names = ['rhettinger', 'paul.j3', 'miss-islington', 'remi.lapeyre']
pr_nums = ['20623', '20664']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue40862'
versions = ['Python 3.9', 'Python 3.10']

Activity

1. remilapeyre commented on Jun 4, 2020

   

   remilapeyremannequin

   on Jun 4, 2020

   MannequinAuthor

   More actions

   The action is used to store None, True or False when an argument like --foo or --no-foo is given to the cli so it has no used for this action, but it is accepted without warning:

   Python 3.10.0a0 (heads/bpo-wip:6e23a9c82b, Jun  4 2020, 13:41:35) 
   [Clang 11.0.3 (clang-1103.0.32.62)] on darwin
   Type "help", "copyright", "credits" or "license" for more information.
   >>> import argparse
   >>> parser = argparse.ArgumentParser()
   >>> parser.add_argument('--foo', const='this_is_not_used', action=argparse.BooleanOptionalAction)
   BooleanOptionalAction(option_strings=['--foo', '--no-foo'], dest='foo', nargs=0, const=None, default=None, type=None, choices=None, help=None, metavar=None)
   >>> args = parser.parse_args()
   >>> args
   Namespace(foo=None)

   We could either always refuse this argument, or accepted and raise ValueError if it is different than None. The attached PR does the first.
2. remilapeyre

   added

   3.9 (EOL)end of lifeend of life

   3.10 (EOL)end of lifeend of life

   stdlibStandard Library Python modules in the Lib/ directoryStandard Library Python modules in the Lib/ directory

   on Jun 4, 2020
3. remilapeyre

   changed the title [-]argparse.BooleanOptionalAction accept and silently its the const argument[/-] [+]argparse.BooleanOptionalAction accept and silently discard its the const argument[/+] on Jun 4, 2020
4. remilapeyre

   changed the title [-]argparse.BooleanOptionalAction accept and silently its the const argument[/-] [+]argparse.BooleanOptionalAction accept and silently discard its the const argument[/+] on Jun 4, 2020
5. rhettinger commented on Jun 5, 2020

   

   rhettinger

   on Jun 5, 2020

   Contributor

   More actions

   ISTM this should be addressed through documentation rather than by breaking currently deployed code that may have specified a default that already matches what the action does.
6. remilapeyre commented on Jun 5, 2020

   

   remilapeyremannequin

   on Jun 5, 2020

   MannequinAuthor

   More actions

   argparse.BooleanOptionalAction was introduced in Python3.9 so there is no code there should be no code that already rely on it.
7. rhettinger commented on Jun 5, 2020

   

   rhettinger

   on Jun 5, 2020

   Contributor

   More actions

   Right. Go ahead :-)
8. rhettinger commented on Jun 5, 2020

   

   rhettinger

   on Jun 5, 2020

   Contributor

   More actions

   New changeset b084d1b by Rémi Lapeyre in branch 'master':
   bpo-40862: Raise TypeError when const is given to argparse.BooleanOptionalAction (GH-20623)
   b084d1b
9. rhettinger commented on Jun 6, 2020

   

   rhettinger

   on Jun 6, 2020

   Contributor

   More actions

   New changeset d5e7348 by Miss Islington (bot) in branch '3.9':
   bpo-40862: Raise TypeError when const is given to argparse.BooleanOptionalAction (GH-20623) (GH-20664)
   d5e7348
10. rhettinger

    closed this as completedon Jun 6, 2020
11. rhettinger

    closed this as completedon Jun 6, 2020
12. ezio-melotti

    transferred this issue fromon Apr 10, 2022

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