Description

gaborbernat

opened on Oct 8, 2025

Issue body actions

Bug report

Bug description:

Here's an example script that replicates the problem:

from __future__ import annotations

import os
from argparse import ArgumentParser
from contextlib import suppress
from unittest.mock import patch

os.environ["FORCE_COLOR"] = "1"

parser = ArgumentParser(description="argparse tester", prog="complex")
parser.add_argument("--root", action="store_true", help="root flag")
sub = parser.add_subparsers(dest="command")
sub.add_parser("demo")

with suppress(SystemExit):
    parser.parse_args(["demo", "--help"])

with patch.dict(os.environ, {"NO_COLOR": "1"}, clear=False):
    parser.parse_args(["demo", "--help"])

You can see the first invocation prints everything in color, while the second only the sub-command:

This is because https://github.com/python/cpython/blame/main/Lib/argparse.py#L1966 passes through the prog formatted and not as raw. This example is contrived a bit to have a minimal demonstration, the actual issue I'm facing is in https://github.com/tox-dev/sphinx-argparse-cli where I'm reading this value directly to generate Sphinx documentation from this.

CPython versions tested on:

3.14, 3.15

Operating systems tested on:

Linux, macOS

Linked PRs

• GH-139809: Fix argparse subcommand prog not respecting color environment variables #139818
• [3.14] GH-139809: Fix argparse subcommand prog not respecting color environment variables (GH-139818) #139866

Activity

1. gaborbernat

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Oct 8, 2025
2. savannahostrowski

   added

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

   on Oct 8, 2025
3. savannahostrowski

   self-assigned this

   on Oct 8, 2025
4. StanFromIreland

   added this to Argparse issueson Oct 8, 2025
5. mpkocher commented on Oct 8, 2025

   

   mpkocher

   on Oct 8, 2025

   Contributor

   More actions

   As an aside, you can use parser = ArgumentParser(description="argparse tester", prog="complex", exit_on_error=False) to make testing easier.

   >>> from argparse import ArgumentParser
   >>> parser = ArgumentParser(description="argparse tester", prog="complex", exit_on_error=False)
   >>> parser.parse_args(['dragons'])
   Traceback (most recent call last):
     File "<python-input-2>", line 1, in <module>
       parser.parse_args(['dragons'])
       ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
   (snip...)
       raise ArgumentError(None, msg)
   argparse.ArgumentError: unrecognized arguments: dragons
   >>>
6. savannahostrowski

   added

   3.14bugs and security fixesbugs and security fixes

   3.15bugs and security fixesbugs and security fixes

   on Oct 8, 2025
7. savannahostrowski commented on Oct 9, 2025

   

   savannahostrowski

   on Oct 9, 2025

   Member

   More actions

   Hey - thanks for filing this. Looks like we missed applying _decolor here when we landed in #132323. I've opened a PR to fix this.
8. savannahostrowski

   added a commit that references this issue on Oct 9, 2025

   GH-139809: Fix argparse subcommand prog not respecting color environm…

   9fc4366
9. miss-islington

   added a commit that references this issue on Oct 9, 2025

   pythonGH-139809: Fix argparse subcommand prog not respecting color en…

   c898f24
10. savannahostrowski

    added a commit that references this issue on Oct 9, 2025

    [3.14] GH-139809: Fix argparse subcommand prog not respecting color e…

    af1cb1c
11. savannahostrowski

    closed this as completedon Oct 9, 2025
12. github-project-automation

    moved this to Doc issues in Argparse issueson Oct 9, 2025

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