argparse optionals with nargs='?', '*' or '+' can't be followed by positionals

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#53,584 27 comments 3 reactions 0 assignees View on GitHub

@stephenfin is already working on this.

Since Mar 27, 2026.

Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
15/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Stale
Tech stack
python
Domain
cli

Research direction

Start with the linked PR #146513 and the attached test_9338.py artifact, then review the other issue9338 patch files listed in the report. The work is done when argparse behavior for optional arguments using nargs='?', '*' or '+' followed by positionals is covered and the relevant tests pass.

Written by the indexing model from the issue text.

Description

3.10 3.11 3.12 3.13 3.14 3.9 (EOL) stdlib type-bug
BPO 9338
Nosy @rhettinger, @jwilk, @merwok, @berkerpeksag, @kernc, @jacksonriley, @iritkatriel
Files
  • test_pos_after_var_args.patch
  • issue9338_argparse.patch
  • issue9338_3.patch
  • test_9338.py
  • issue9338_7.patch
    		•

    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 2010-07-23.10:46:27.420>
labels = ['type-bug', 'library', '3.9', '3.10', '3.11']
title = "argparse optionals with nargs='?', '*' or '+' can't be followed by positionals"
updated_at = <Date 2022-02-17.10:51:52.599>
user = 'https://bugs.python.org/bethard'

    bugs.python.org fields:

    activity = <Date 2022-02-17.10:51:52.599>
actor = 'wdoekes'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2010-07-23.10:46:27.420>
creator = 'bethard'
dependencies = []
files = ['18328', '19691', '30296', '30297', '30350']
hgrepos = []
issue_num = 9338
keywords = ['patch']
message_count = 25.0
messages = ['111270', '111280', '111282', '112511', '121013', '121720', '122016', '141639', '141660', '166237', '166239', '189198', '189200', '189470', '189472', '189867', '189868', '200858', '200862', '216990', '285866', '314213', '355748', '370265', '408332']
nosy_count = 19.0
nosy_names = ['rhettinger', 'bethard', 'wrobell', 'jwilk', 'eric.araujo', 'TD22057', 'wdoekes', 'catherine', 'elsdoerfer', 'Kotan', 'berker.peksag', 'paul.j3', 'phawkins', 'kernc', 'sebix', 'extmind', 'jacksonriley', 'iritkatriel', 'kottalovag']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue9338'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']

    Linked PRs
    • gh-146513
    Dominant language
    Python
    Stars
    77.2k
    Forks
    36k
    Avg merge
    1d 9h
    Merged PRs (30d)
    558

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