[3.13] gh-121018: Fix more cases of exiting in argparse when exit_on_error=False (GH-121056)

Lib/argparse.py

@@ -1819,7 +1819,7 @@ def _get_kwargs(self):
     # ==================================
     def add_subparsers(self, **kwargs):
         if self._subparsers is not None:
-            self.error(_('cannot have multiple subparser arguments'))
+            raise ArgumentError(None, _('cannot have multiple subparser arguments'))
 
         # add the parser class to the arguments if it's not present
         kwargs.setdefault('parser_class', type(self))
@@ -1874,7 +1874,8 @@ def parse_args(self, args=None, namespace=None):
             msg = _('unrecognized arguments: %s') % ' '.join(argv)
             if self.exit_on_error:
                 self.error(msg)
-            raise ArgumentError(None, msg)
+            else:
+                raise ArgumentError(None, msg)
         return args
 
     def parse_known_args(self, args=None, namespace=None):
@@ -2163,7 +2164,7 @@ def consume_positionals(start_index):
                                 self._get_value(action, action.default))
 
         if required_actions:
-            self.error(_('the following arguments are required: %s') %
+            raise ArgumentError(None, _('the following arguments are required: %s') %
                        ', '.join(required_actions))
 
         # make sure all required groups had one option present
@@ -2179,7 +2180,7 @@ def consume_positionals(start_index):
                              for action in group._group_actions
                              if action.help is not SUPPRESS]
                     msg = _('one of the arguments %s is required')
-                    self.error(msg % ' '.join(names))
+                    raise ArgumentError(None, msg % ' '.join(names))
 
         # return the updated namespace and the extra arguments
         return namespace, extras
@@ -2206,7 +2207,7 @@ def _read_args_from_files(self, arg_strings):
                         arg_strings = self._read_args_from_files(arg_strings)
                         new_arg_strings.extend(arg_strings)
                 except OSError as err:
-                    self.error(str(err))
+                    raise ArgumentError(None, str(err))
 
         # return the modified argument list
         return new_arg_strings
@@ -2286,7 +2287,7 @@ def _parse_optional(self, arg_string):
                 for action, option_string, sep, explicit_arg in option_tuples])
             args = {'option': arg_string, 'matches': options}
             msg = _('ambiguous option: %(option)s could match %(matches)s')
-            self.error(msg % args)
+            raise ArgumentError(None, msg % args)
 
         # if exactly one action matched, this segmentation is good,
         # so return the parsed action
@@ -2346,7 +2347,7 @@ def _get_option_tuples(self, option_string):
 
         # shouldn't ever get here
         else:
-            self.error(_('unexpected option string: %s') % option_string)
+            raise ArgumentError(None, _('unexpected option string: %s') % option_string)
 
         # return the collected option tuples
         return result
@@ -2403,8 +2404,11 @@ def _get_nargs_pattern(self, action):
     def parse_intermixed_args(self, args=None, namespace=None):
         args, argv = self.parse_known_intermixed_args(args, namespace)
         if argv:
-            msg = _('unrecognized arguments: %s')
-            self.error(msg % ' '.join(argv))
+            msg = _('unrecognized arguments: %s') % ' '.join(argv)
+            if self.exit_on_error:
+                self.error(msg)
+            else:
+                raise ArgumentError(None, msg)
         return args
 
     def parse_known_intermixed_args(self, args=None, namespace=None):

Lib/test/test_argparse.py

@@ -2190,7 +2190,9 @@ def _get_parser(self, subparser_help=False, prefix_chars=None,
         else:
             subparsers_kwargs['help'] = 'command help'
         subparsers = parser.add_subparsers(**subparsers_kwargs)
-        self.assertArgumentParserError(parser.add_subparsers)
+        self.assertRaisesRegex(argparse.ArgumentError,
+                               'cannot have multiple subparser arguments',
+                               parser.add_subparsers)
 
         # add first sub-parser
         parser1_kwargs = dict(description='1 description')
@@ -6085,7 +6087,8 @@ def test_help_with_metavar(self):
 class TestExitOnError(TestCase):
 
     def setUp(self):
-        self.parser = argparse.ArgumentParser(exit_on_error=False)
+        self.parser = argparse.ArgumentParser(exit_on_error=False,
+                                              fromfile_prefix_chars='@')
         self.parser.add_argument('--integers', metavar='N', type=int)
 
     def test_exit_on_error_with_good_args(self):
@@ -6096,9 +6099,44 @@ def test_exit_on_error_with_bad_args(self):
         with self.assertRaises(argparse.ArgumentError):
             self.parser.parse_args('--integers a'.split())
 
-    def test_exit_on_error_with_unrecognized_args(self):
-        with self.assertRaises(argparse.ArgumentError):
-            self.parser.parse_args('--foo bar'.split())
+    def test_unrecognized_args(self):
+        self.assertRaisesRegex(argparse.ArgumentError,
+                               'unrecognized arguments: --foo bar',
+                               self.parser.parse_args, '--foo bar'.split())
+
+    def test_unrecognized_intermixed_args(self):
+        self.assertRaisesRegex(argparse.ArgumentError,
+                               'unrecognized arguments: --foo bar',
+                               self.parser.parse_intermixed_args, '--foo bar'.split())
+
+    def test_required_args(self):
+        self.parser.add_argument('bar')
+        self.parser.add_argument('baz')
+        self.assertRaisesRegex(argparse.ArgumentError,
+                               'the following arguments are required: bar, baz',
+                               self.parser.parse_args, [])
+
+    def test_required_mutually_exclusive_args(self):
+        group = self.parser.add_mutually_exclusive_group(required=True)
+        group.add_argument('--bar')
+        group.add_argument('--baz')
+        self.assertRaisesRegex(argparse.ArgumentError,
+                               'one of the arguments --bar --baz is required',
+                               self.parser.parse_args, [])
+
+    def test_ambiguous_option(self):
+        self.parser.add_argument('--foobaz')
+        self.parser.add_argument('--fooble', action='store_true')
+        self.assertRaisesRegex(argparse.ArgumentError,
+                               "ambiguous option: --foob could match --foobaz, --fooble",
+                               self.parser.parse_args, ['--foob'])
+
+    def test_os_error(self):
+        self.parser.add_argument('file')
+        self.assertRaisesRegex(argparse.ArgumentError,
+                               "No such file or directory: 'no-such-file'",
+                               self.parser.parse_args, ['@no-such-file'])
+
 
 def tearDownModule():
     # Remove global references to avoid looking like we have refleaks.

Misc/NEWS.d/next/Library/2024-06-26-03-04-24.gh-issue-121018.clVSc4.rst

@@ -0,0 +1,2 @@
+Fixed other issues where :class:`argparse.ArgumentParser` did not honor
+``exit_on_error=False``.