From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Date: Tue, 9 Jun 2026 15:44:07 +0000 (+0200)
Subject: [3.13] GH-61082: Clarify nargs='*' positional default behavior (GH-150989) (#151170)
X-Git-Tag: v3.13.14~17
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=558764600ffa7406affc617b09b14d4937f259c4;p=thirdparty%2FPython%2Fcpython.git

[3.13] GH-61082: Clarify nargs='*' positional default behavior (GH-150989) (#151170)

GH-61082: Clarify nargs='*' positional default behavior (GH-150989)
(cherry picked from commit bc37a227b2f481d0f260f9beae5229e8d432a0cc)

Co-authored-by: Savannah Ostrowski <savannah@python.org>
---

diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
index 89b9faf9f60d..fa5b92ed81b8 100644
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -953,6 +953,10 @@ is used when no command-line argument was present::
    >>> parser.parse_args([])
    Namespace(foo=42)
 
+Because ``nargs='*'`` gathers any supplied values into a list, an absent
+positional argument yields an empty list (``[]``). Only a non-``None``
+*default* overrides this (so ``default=None`` still gives ``[]``).
+
 For required_ arguments, the ``default`` value is ignored. For example, this
 applies to positional arguments with nargs_ values other than ``?`` or ``*``,
 or optional arguments marked as ``required=True``.