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

* parse_intermixed_args() now raises ArgumentError instead of calling
  error() if exit_on_error is false.
* Internal code now always raises ArgumentError instead of calling
  error(). It is then caught at the higher level and error() is called if
  exit_on_error is true.

1 files changed, 13 insertions, 9 deletions

diff --git a/Lib/argparse.py b/Lib/argparse.py
index f1c3808..8318911 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -1791,7 +1791,7 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
     # ==================================
     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))
@@ -1846,7 +1846,8 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
             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):
@@ -2135,7 +2136,7 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
                                 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
@@ -2151,7 +2152,7 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
                              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
@@ -2178,7 +2179,7 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
                         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
@@ -2258,7 +2259,7 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
                 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
@@ -2318,7 +2319,7 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
 
         # 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
@@ -2375,8 +2376,11 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
     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):