From 6da2cf30311f97d23a7121f8c02f9123674194b4 Mon Sep 17 00:00:00 2001
From: Eric Lin <anselor@gmail.com>
Date: Fri, 12 Jun 2020 20:44:10 -0400
Subject: Some minor cleanup of how imports work. Fixed issue with help
 documentation for CommandSet commands. Issue #943

---
 cmd2/__init__.py           |  1 +
 cmd2/cmd2.py               |  8 ++++----
 cmd2/command_definition.py | 21 ++++++++++++++++++---
 3 files changed, 23 insertions(+), 7 deletions(-)

(limited to 'cmd2')

diff --git a/cmd2/__init__.py b/cmd2/__init__.py
index c3c1f87e..70a52f70 100644
--- a/cmd2/__init__.py
+++ b/cmd2/__init__.py
@@ -28,6 +28,7 @@ if cmd2_parser_module is not None:
 # Get the current value for argparse_custom.DEFAULT_ARGUMENT_PARSER
 from .argparse_custom import DEFAULT_ARGUMENT_PARSER
 from .cmd2 import Cmd
+from .command_definition import CommandSet, with_default_category, register_command
 from .constants import COMMAND_NAME, DEFAULT_SHORTCUTS
 from .decorators import with_argument_list, with_argparser, with_argparser_and_unknown_args, with_category
 from .exceptions import Cmd2ArgparseError, SkipPostcommandHooks
diff --git a/cmd2/cmd2.py b/cmd2/cmd2.py
index 9a98b550..4100ec08 100644
--- a/cmd2/cmd2.py
+++ b/cmd2/cmd2.py
@@ -46,7 +46,7 @@ from typing import Any, AnyStr, Callable, Dict, Iterable, List, Mapping, Optiona
 from . import ansi, constants, plugin, utils
 from .argparse_custom import DEFAULT_ARGUMENT_PARSER, CompletionItem
 from .clipboard import can_clip, get_paste_buffer, write_to_paste_buffer
-from .command_definition import _UNBOUND_COMMANDS, CommandSet, _PartialPassthru
+from .command_definition import _UNBOUND_COMMANDS, CommandSet, _partial_passthru
 from .constants import COMMAND_FUNC_PREFIX, COMPLETER_FUNC_PREFIX, HELP_FUNC_PREFIX
 from .decorators import with_argparser
 from .exceptions import Cmd2ShlexError, EmbeddedConsoleExit, EmptyStatement, RedirectionError, SkipPostcommandHooks
@@ -428,7 +428,7 @@ class Cmd(cmd.Cmd):
                 assert getattr(self, method[0], None) is None, \
                     'In {}: Duplicate command function: {}'.format(cmdset_type.__name__, method[0])
 
-                command_wrapper = _PartialPassthru(method[1], self)
+                command_wrapper = _partial_passthru(method[1], self)
                 setattr(self, method[0], command_wrapper)
 
                 command = method[0][len(COMMAND_FUNC_PREFIX):]
@@ -436,11 +436,11 @@ class Cmd(cmd.Cmd):
                 completer_func_name = COMPLETER_FUNC_PREFIX + command
                 cmd_completer = getattr(cmdset, completer_func_name, None)
                 if cmd_completer and not getattr(self, completer_func_name, None):
-                    completer_wrapper = _PartialPassthru(cmd_completer, self)
+                    completer_wrapper = _partial_passthru(cmd_completer, self)
                     setattr(self, completer_func_name, completer_wrapper)
                 cmd_help = getattr(cmdset, HELP_FUNC_PREFIX + command, None)
                 if cmd_help and not getattr(self, HELP_FUNC_PREFIX + command, None):
-                    help_wrapper = _PartialPassthru(cmd_help, self)
+                    help_wrapper = _partial_passthru(cmd_help, self)
                     setattr(self, HELP_FUNC_PREFIX + command, help_wrapper)
 
     def add_settable(self, settable: Settable) -> None:
diff --git a/cmd2/command_definition.py b/cmd2/command_definition.py
index f08040bb..a235525d 100644
--- a/cmd2/command_definition.py
+++ b/cmd2/command_definition.py
@@ -29,10 +29,15 @@ Registered command tuples. (command, do_ function, complete_ function, help_ fun
 """
 
 
-class _PartialPassthru(functools.partial):
+def _partial_passthru(func: Callable, *args, **kwargs) -> functools.partial:
     """
-    Wrapper around partial function that passes through getattr, setattr, and dir to the wrapped function.
-    This allows for CommandSet functions to be wrapped while maintaining the decorated properties
+    Constructs a partial function that passes arguments through to the wrapped function.
+    Must construct a new type every time so that each wrapped function's __doc__ can be copied correctly.
+
+    :param func: wrapped function
+    :param args: positional arguments
+    :param kwargs: keyword arguments
+    :return: partial function that exposes attributes of wrapped function
     """
     def __getattr__(self, item):
         return getattr(self.func, item)
@@ -43,6 +48,16 @@ class _PartialPassthru(functools.partial):
     def __dir__(self) -> Iterable[str]:
         return dir(self.func)
 
+    passthru_type = type('PassthruPartial' + func.__name__,
+                         (functools.partial,),
+                         {
+                             '__getattr__': __getattr__,
+                             '__setattr__': __setattr__,
+                             '__dir__': __dir__,
+                         })
+    passthru_type.__doc__ = func.__doc__
+    return passthru_type(func, *args, **kwargs)
+
 
 def register_command(cmd_func: Callable[['Cmd', Union['Statement', 'argparse.Namespace']], None]):
     """
-- 
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