Add required args to subcommand program

cmd2/__init__.py

@@ -5,12 +5,8 @@
 
 import sys
 
-# For python 3.8 and later
-if sys.version_info >= (3, 8):
-    import importlib.metadata as importlib_metadata
-else:
-    # For everyone else
-    import importlib_metadata
+import importlib.metadata as importlib_metadata
+
 try:
     __version__ = importlib_metadata.version(__name__)
 except importlib_metadata.PackageNotFoundError:  # pragma: no cover

cmd2/cmd2.py

@@ -700,10 +700,7 @@ def _build_parser(
         elif callable(parser_builder):
             parser = parser_builder()
         elif isinstance(parser_builder, argparse.ArgumentParser):
-            if sys.version_info >= (3, 6, 4):
-                parser = copy.deepcopy(parser_builder)
-            else:  # pragma: no cover
-                parser = parser_builder
+            parser = copy.deepcopy(parser_builder)
         return parser
 
     def _register_command_parser(self, command: str, command_method: Callable[..., Any]) -> None:
@@ -778,9 +775,9 @@ def unregister_command_set(self, cmdset: CommandSet) -> None:
             cmdset.on_unregister()
             self._unregister_subcommands(cmdset)
 
-            methods = inspect.getmembers(
+            methods: List[Tuple[str, Callable[[Any], Any]]] = inspect.getmembers(
                 cmdset,
-                predicate=lambda meth: isinstance(meth, Callable)  # type: ignore[arg-type, var-annotated]
+                predicate=lambda meth: isinstance(meth, Callable)  # type: ignore[arg-type]
                 and hasattr(meth, '__name__')
                 and meth.__name__.startswith(COMMAND_FUNC_PREFIX),
             )
@@ -809,9 +806,9 @@ def unregister_command_set(self, cmdset: CommandSet) -> None:
             self._installed_command_sets.remove(cmdset)
 
     def _check_uninstallable(self, cmdset: CommandSet) -> None:
-        methods = inspect.getmembers(
+        methods: List[Tuple[str, Callable[[Any], Any]]] = inspect.getmembers(
             cmdset,
-            predicate=lambda meth: isinstance(meth, Callable)  # type: ignore[arg-type, var-annotated]
+            predicate=lambda meth: isinstance(meth, Callable)  # type: ignore[arg-type]
             and hasattr(meth, '__name__')
             and meth.__name__.startswith(COMMAND_FUNC_PREFIX),
         )
@@ -3328,19 +3325,14 @@ def _cmdloop(self) -> None:
     #############################################################
 
     # Top-level parser for alias
-    @staticmethod
-    def _build_alias_parser() -> argparse.ArgumentParser:
-        alias_description = (
-            "Manage aliases\n" "\n" "An alias is a command that enables replacement of a word by another string."
-        )
-        alias_epilog = "See also:\n" "  macro"
-        alias_parser = argparse_custom.DEFAULT_ARGUMENT_PARSER(description=alias_description, epilog=alias_epilog)
-        alias_subparsers = alias_parser.add_subparsers(dest='subcommand', metavar='SUBCOMMAND')
-        alias_subparsers.required = True
-        return alias_parser
+    alias_description = "Manage aliases\n" "\n" "An alias is a command that enables replacement of a word by another string."
+    alias_epilog = "See also:\n" "  macro"
+    alias_parser = argparse_custom.DEFAULT_ARGUMENT_PARSER(description=alias_description, epilog=alias_epilog)
+    alias_subparsers = alias_parser.add_subparsers(dest='subcommand', metavar='SUBCOMMAND')
+    alias_subparsers.required = True
 
     # Preserve quotes since we are passing strings to other commands
-    @with_argparser(_build_alias_parser, preserve_quotes=True)
+    @with_argparser(alias_parser, preserve_quotes=True)
     def do_alias(self, args: argparse.Namespace) -> None:
         """Manage aliases"""
         # Call handler for whatever subcommand was selected

cmd2/decorators.py

@@ -209,6 +209,7 @@ def _set_parser_prog(parser: argparse.ArgumentParser, prog: str) -> None:
     """
     # Set the prog value for this parser
     parser.prog = prog
+    req_args: List[str] = []
 
     # Set the prog value for the parser's subcommands
     for action in parser._actions:
@@ -233,13 +234,20 @@ def _set_parser_prog(parser: argparse.ArgumentParser, prog: str) -> None:
                 if subcmd_parser in processed_parsers:
                     continue
 
-                subcmd_prog = parser.prog + ' ' + subcmd_name
+                subcmd_prog = parser.prog
+                if req_args:
+                    subcmd_prog += " " + " ".join(req_args)
+                subcmd_prog += " " + subcmd_name
                 _set_parser_prog(subcmd_parser, subcmd_prog)
                 processed_parsers.append(subcmd_parser)
 
             # We can break since argparse only allows 1 group of subcommands per level
             break
 
+        # Need to save required args so they can be prepended to the subcommand usage
+        elif action.required:
+            req_args.append(action.dest)
+
 
 #: Function signature for a Command Function that uses an argparse.ArgumentParser to process user input
 #: and optionally returns a boolean

docs/features/argument_processing.rst

@@ -75,13 +75,6 @@ Here's what it looks like::
          for i in range(min(repetitions, self.maxrepeats)):
             self.poutput(arg)
 
-.. warning::
-
-    It is important that each command which uses the ``@with_argparser``
-    decorator be passed a unique instance of a parser since command-specific
-    changes could be made to it.
-
-
 .. note::
 
    The ``@with_argparser`` decorator sets the ``prog`` variable in the argument