https://github.com/python/cpython/commit/bc37a227b2f481d0f260f9beae5229e8d432a0cc
commit: bc37a227b2f481d0f260f9beae5229e8d432a0cc
branch: main
author: Savannah Ostrowski <[email protected]>
committer: savannahostrowski <[email protected]>
date: 2026-06-09T15:37:24Z
summary:
GH-61082: Clarify nargs='*' positional default behavior (#150989)
files:
M Doc/library/argparse.rst
diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
index 622f844a4a0b82..4c588d447a9a7c 100644
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -1051,6 +1051,10 @@ 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``.
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