Removed sub-class and instead patch argparse._SubParsersAction

3 files changed, 30 insertions, 28 deletions

diff --git a/cmd2/argparse_custom.py b/cmd2/argparse_custom.py
index 9dde5347..6cfa66ae 100644
--- a/cmd2/argparse_custom.py
+++ b/cmd2/argparse_custom.py
@@ -528,6 +528,31 @@ def _match_argument_wrapper(self, action, arg_strings_pattern) -> int:
 # noinspection PyProtectedMember
 argparse.ArgumentParser._match_argument = _match_argument_wrapper
 
+
+############################################################################################################
+# Patch argparse._SubParsersAction to add remove_parser function
+############################################################################################################
+
+def _SubParsersAction_remove_parser(self, name):
+    """Removes a sub-parser from the sub-parsers group"""
+    for choice_action in self._choices_actions:
+        if choice_action.dest == name:
+            self._choices_actions.remove(choice_action)
+            break
+
+    subparser = self._name_parser_map[name]
+    to_remove = []
+    for name, parser in self._name_parser_map.items():
+        if parser is subparser:
+            to_remove.append(name)
+    for name in to_remove:
+        del self._name_parser_map[name]
+
+
+# noinspection PyProtectedMember
+setattr(argparse._SubParsersAction, 'remove_parser', _SubParsersAction_remove_parser)
+
+
 ############################################################################################################
 # Unless otherwise noted, everything below this point are copied from Python's
 # argparse implementation with minor tweaks to adjust output.
@@ -724,24 +749,6 @@ class Cmd2HelpFormatter(argparse.RawTextHelpFormatter):
         return result
 
 
-class _UnloadableSubParsersAction(argparse._SubParsersAction):
-    """Extends the argparse internal SubParsers action to allow sub-parsers to be removed dynamically"""
-    def remove_parser(self, name):
-        """Removes a sub-parser from the sub-parsers group"""
-        for choice_action in self._choices_actions:
-            if choice_action.dest == name:
-                self._choices_actions.remove(choice_action)
-                break
-
-        subparser = self._name_parser_map[name]
-        to_remove = []
-        for name, parser in self._name_parser_map.items():
-            if parser is subparser:
-                to_remove.append(name)
-        for name in to_remove:
-            del self._name_parser_map[name]
-
-
 # noinspection PyCompatibility
 class Cmd2ArgumentParser(argparse.ArgumentParser):
     """Custom ArgumentParser class that improves error and help output"""
@@ -772,22 +779,17 @@ class Cmd2ArgumentParser(argparse.ArgumentParser):
             conflict_handler=conflict_handler,
             add_help=add_help,
             allow_abbrev=allow_abbrev)
-        self.register('action', 'unloadable_parsers', _UnloadableSubParsersAction)
 
-    def add_subparsers(self, unloadable: bool = False, **kwargs):
+    def add_subparsers(self, **kwargs):
         """
         Custom override. Sets a default title if one was not given.
 
-        :param unloadable: Flag whether this sub-parsers group will support unloading parsers
         :param kwargs: additional keyword arguments
         :return: argparse Subparser Action
         """
         if 'title' not in kwargs:
             kwargs['title'] = 'subcommands'
 
-        if unloadable:
-            kwargs['action'] = 'unloadable_parsers'
-
         return super().add_subparsers(**kwargs)
 
     def error(self, message: str) -> None:
diff --git a/cmd2/cmd2.py b/cmd2/cmd2.py
index e15a856e..c933db99 100644
--- a/cmd2/cmd2.py
+++ b/cmd2/cmd2.py
@@ -43,7 +43,7 @@ from contextlib import redirect_stdout
 from typing import Any, Callable, Dict, Iterable, List, Mapping, Optional, Tuple, Type, Union
 
 from . import ansi, constants, plugin, utils
-from .argparse_custom import DEFAULT_ARGUMENT_PARSER, CompletionItem, _UnloadableSubParsersAction
+from .argparse_custom import DEFAULT_ARGUMENT_PARSER, CompletionItem
 from .clipboard import can_clip, get_paste_buffer, write_to_paste_buffer
 from .command_definition import CommandSet, _partial_passthru
 from .constants import COMMAND_FUNC_PREFIX, COMPLETER_FUNC_PREFIX, HELP_FUNC_PREFIX
@@ -567,7 +567,7 @@ class Cmd(cmd.Cmd):
             subcmd_parser.set_defaults(handler=command_handler)
 
             for action in command_parser._actions:
-                if isinstance(action, _UnloadableSubParsersAction):
+                if isinstance(action, argparse._SubParsersAction):
                     action.add_parser(subcommand_name, parents=[subcmd_parser], **parser_args)
 
     def _unregister_subcommands(self, cmdset: Union[CommandSet, 'Cmd']) -> None:
@@ -604,7 +604,7 @@ class Cmd(cmd.Cmd):
                                 .format(command_name, str(method)))
 
             for action in command_parser._actions:
-                if isinstance(action, _UnloadableSubParsersAction):
+                if isinstance(action, argparse._SubParsersAction):
                     action.remove_parser(subcommand_name)
 
     def add_settable(self, settable: Settable) -> None:
diff --git a/isolated_tests/test_commandset/test_commandset.py b/isolated_tests/test_commandset/test_commandset.py
index 98385772..f16a6ff4 100644
--- a/isolated_tests/test_commandset/test_commandset.py
+++ b/isolated_tests/test_commandset/test_commandset.py
@@ -272,7 +272,7 @@ class LoadableBase(cmd2.CommandSet):
         self._dummy = dummy  # prevents autoload
 
     cut_parser = cmd2.Cmd2ArgumentParser('cut')
-    cut_subparsers = cut_parser.add_subparsers(title='item', help='item to cut', unloadable=True)
+    cut_subparsers = cut_parser.add_subparsers(title='item', help='item to cut')
 
     @cmd2.with_argparser(cut_parser)
     def do_cut(self, ns: argparse.Namespace):