Use the "no" prefix instead of "no-" for single-dash options.

Author: serhiy-storchaka

Doc/library/argparse.rst

@@ -1446,7 +1446,7 @@ this API may be passed as the ``action`` parameter to
        Namespace(foo=False)
 
    Single-dash long options are also supported.
-   For example, negative option ``-no-foo`` is automatically added for
+   For example, negative option ``-nofoo`` is automatically added for
    positive option ``-foo``.
    But no additional options are added for short options such as ``-f``.
 

Lib/argparse.py

@@ -944,10 +944,10 @@ def __init__(self,
                 _option_strings.append(option_string)
                 neg_option_strings.append(option_string)
             elif len(option_string) > 2 and option_string[0] != option_string[1]:
-                if option_string.startswith('no-', 1):
+                if option_string.startswith('no', 1):
                     raise ValueError(f'invalid option name {option_string!r} '
                                      f'for BooleanOptionalAction')
-                option_string = option_string[:1] + 'no-' + option_string[1:]
+                option_string = option_string[:1] + 'no' + option_string[1:]
                 _option_strings.append(option_string)
                 neg_option_strings.append(option_string)
 

Lib/test/test_argparse.py

@@ -811,20 +811,20 @@ class TestBooleanOptionalActionSingleDash(ParserTestCase):
     argument_signatures = [
         Sig('-foo', '-x', action=argparse.BooleanOptionalAction),
     ]
-    failures = ['--foo', '--no-foo', '-no-x']
+    failures = ['--foo', '--no-foo', '-no-foo', '-no-x', '-nox']
     successes = [
         ('', NS(foo=None)),
         ('-foo', NS(foo=True)),
-        ('-no-foo', NS(foo=False)),
+        ('-nofoo', NS(foo=False)),
         ('-x', NS(foo=True)),
     ]
 
     def test_invalid_name(self):
         parser = argparse.ArgumentParser()
         with self.assertRaises(ValueError) as cm:
-            parser.add_argument('-no-foo', action=argparse.BooleanOptionalAction)
+            parser.add_argument('-nofoo', action=argparse.BooleanOptionalAction)
         self.assertEqual(str(cm.exception),
-                         "invalid option name '-no-foo' for BooleanOptionalAction")
+                         "invalid option name '-nofoo' for BooleanOptionalAction")
 
 class TestBooleanOptionalActionAlternatePrefixChars(ParserTestCase):
     """Tests BooleanOptionalAction with custom prefixes"""
@@ -855,11 +855,13 @@ class TestBooleanOptionalActionSingleAlternatePrefixChar(ParserTestCase):
     argument_signatures = [
         Sig('+foo', '+x', action=argparse.BooleanOptionalAction),
     ]
-    failures = ['++foo', '++no-foo', '-no-foo', '+no-x', '-no-x']
+    failures = ['++foo', '++no-foo', '++nofoo',
+                '-no-foo', '-nofoo', '+no-foo', '-nofoo',
+                '+no-x', '+nox', '-no-x', '-nox']
     successes = [
         ('', NS(foo=None)),
         ('+foo', NS(foo=True)),
-        ('+no-foo', NS(foo=False)),
+        ('+nofoo', NS(foo=False)),
         ('+x', NS(foo=True)),
     ]
 
@@ -869,9 +871,9 @@ def test_invalid_name(self):
                 'BooleanOptionalAction.*is not valid for positional arguments'):
             parser.add_argument('-foo', action=argparse.BooleanOptionalAction)
         with self.assertRaises(ValueError) as cm:
-            parser.add_argument('+no-foo', action=argparse.BooleanOptionalAction)
+            parser.add_argument('+nofoo', action=argparse.BooleanOptionalAction)
         self.assertEqual(str(cm.exception),
-                         "invalid option name '+no-foo' for BooleanOptionalAction")
+                         "invalid option name '+nofoo' for BooleanOptionalAction")
 
 class TestBooleanOptionalActionRequired(ParserTestCase):
     """Tests BooleanOptionalAction required"""