gh-117941: Reject option names starting with "--no-" in argparse.Bool…

…eanOptionalAction They never worked correctly.
python · Oct 23, 2024 · 714c456 · 714c456
1 parent 6f26d49
commit 714c456
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Showing 3 changed files with 12 additions and 0 deletions.
diff --git a/Lib/argparse.py b/Lib/argparse.py
@@ -863,6 +863,9 @@ def __init__(self,
             _option_strings.append(option_string)
 
             if option_string.startswith('--'):
+                if option_string.startswith('--no-'):
+                    raise ValueError(f'invalid option name {option_string!r} '
+                                     f'for BooleanOptionalAction')
                 option_string = '--no-' + option_string[2:]
                 _option_strings.append(option_string)
 

diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
@@ -782,6 +782,13 @@ def test_const(self):
 
         self.assertIn("got an unexpected keyword argument 'const'", str(cm.exception))
 
+    def test_invalid_name(self):
+        parser = argparse.ArgumentParser()
+        with self.assertRaises(ValueError) as cm:
+            parser.add_argument('--no-foo', action=argparse.BooleanOptionalAction)
+        self.assertEqual(str(cm.exception),
+                         "invalid option name '--no-foo' for BooleanOptionalAction")
+
 class TestBooleanOptionalActionRequired(ParserTestCase):
     """Tests BooleanOptionalAction required"""
 

diff --git a/Misc/NEWS.d/next/Library/2024-10-23-20-44-30.gh-issue-117941.Y9jdlW.rst b/Misc/NEWS.d/next/Library/2024-10-23-20-44-30.gh-issue-117941.Y9jdlW.rst
@@ -0,0 +1,2 @@
+:class:`argparse.BooleanOptionalAction` now rejects option names starting
+with ``--no-``.