https://github.com/python/cpython/commit/9944ad388c457325456152257b977410c4ec3593
commit: 9944ad388c457325456152257b977410c4ec3593
branch: main
author: Serhiy Storchaka <[email protected]>
committer: serhiy-storchaka <[email protected]>
date: 2024-10-12T16:04:17+03:00
summary:
gh-85935: Check for nargs=0 for positional arguments in argparse (GH-124839)
Raise ValueError in add_argument() if either explicit nargs=0 or action
that does not consume arguments (like 'store_const' or 'store_true') is
specified for positional argument.
files:
A Misc/NEWS.d/next/Library/2024-10-01-13-11-53.gh-issue-85935.CTwJUy.rst
M Lib/argparse.py
M Lib/test/test_argparse.py
diff --git a/Lib/argparse.py b/Lib/argparse.py
index cbecb3b753c2b9..550415dc93478b 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -1441,11 +1441,17 @@ def add_argument(self, *args, **kwargs):
kwargs['default'] = self.argument_default
# create the action object, and add it to the parser
+ action_name = kwargs.get('action')
action_class = self._pop_action_class(kwargs)
if not callable(action_class):
raise ValueError('unknown action "%s"' % (action_class,))
action = action_class(**kwargs)
+ # raise an error if action for positional argument does not
+ # consume arguments
+ if not action.option_strings and action.nargs == 0:
+ raise ValueError(f'action {action_name!r} is not valid for
positional arguments')
+
# raise an error if the action type is not callable
type_func = self._registry_get('type', action.type, action.type)
if not callable(type_func):
@@ -1554,7 +1560,9 @@ def _get_positional_kwargs(self, dest, **kwargs):
# mark positional arguments as required if at least one is
# always required
nargs = kwargs.get('nargs')
- if nargs not in [OPTIONAL, ZERO_OR_MORE, REMAINDER, SUPPRESS, 0]:
+ if nargs == 0:
+ raise ValueError('nargs for positionals must be != 0')
+ if nargs not in [OPTIONAL, ZERO_OR_MORE, REMAINDER, SUPPRESS]:
kwargs['required'] = True
# return the keyword arguments with no option strings
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index 1fc97de78f7f89..f52a4b6bdd8aca 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -5424,8 +5424,11 @@ def test_no_argument_actions(self):
with self.subTest(attrs=attrs):
self.assertTypeError('-x', action=action, **attrs)
self.assertTypeError('x', action=action, **attrs)
+ self.assertValueError('x', action=action,
+ errmsg=f"action '{action}' is not valid for positional
arguments")
self.assertTypeError('-x', action=action, nargs=0)
- self.assertTypeError('x', action=action, nargs=0)
+ self.assertValueError('x', action=action, nargs=0,
+ errmsg='nargs for positionals must be != 0')
def test_no_argument_no_const_actions(self):
# options with zero arguments
@@ -5445,7 +5448,7 @@ def test_more_than_one_argument_actions(self):
self.assertValueError('-x', nargs=0, action=action,
errmsg=f'nargs for {action_name} actions must be != 0')
self.assertValueError('spam', nargs=0, action=action,
- errmsg=f'nargs for {action_name} actions must be != 0')
+ errmsg='nargs for positionals must be != 0')
# const is disallowed with non-optional arguments
for nargs in [1, '*', '+']:
diff --git
a/Misc/NEWS.d/next/Library/2024-10-01-13-11-53.gh-issue-85935.CTwJUy.rst
b/Misc/NEWS.d/next/Library/2024-10-01-13-11-53.gh-issue-85935.CTwJUy.rst
new file mode 100644
index 00000000000000..553f206bf26337
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-10-01-13-11-53.gh-issue-85935.CTwJUy.rst
@@ -0,0 +1,4 @@
+:meth:`argparse.ArgumentParser.add_argument` now raises an exception if
+an :ref:`action` that does not consume arguments (like 'store_const' or
+'store_true') or explicit ``nargs=0`` are specified for positional
+arguments.
_______________________________________________
Python-checkins mailing list -- [email protected]
To unsubscribe send an email to [email protected]
https://mail.python.org/mailman3/lists/python-checkins.python.org/
Member address: [email protected]
