From 8b5c637f7660454015b4b61d890b0995cb0bf03f Mon Sep 17 00:00:00 2001
From: Tulir Asokan <tulir@maunium.net>
Date: Fri, 18 Jan 2019 22:58:43 +0200
Subject: [PATCH] Fix CommandHandler descriptor

---
 maubot/handlers/command.py | 43 +++++++++++++++++++-------------------
 maubot/plugin_base.py      |  1 -
 2 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/maubot/handlers/command.py b/maubot/handlers/command.py
index 97cbd89..8bd6534 100644
--- a/maubot/handlers/command.py
+++ b/maubot/handlers/command.py
@@ -14,7 +14,7 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 from typing import (Union, Callable, Sequence, Pattern, Awaitable, NewType, Optional, Any, List,
-                    Dict, Tuple, Set)
+                    Dict, Tuple, Set, Type)
 from abc import ABC, abstractmethod
 import asyncio
 import functools
@@ -55,26 +55,27 @@ class CommandHandler:
         self.__mb_event_handler__: bool = True
         self.__mb_event_type__: EventType = EventType.ROOM_MESSAGE
         self.__mb_msgtypes__: List[MessageType] = (MessageType.TEXT,)
-        self.__instance_vars: Dict[str, CommandHandler] = {}
-        self.__class_instance: Any = None
-
-    def __copy__(self) -> 'CommandHandler':
-        new_ch = type(self)(self.__mb_func__)
-        keys = ["parent", "subcommands", "arguments", "help", "get_name", "is_command_match",
-                "require_subcommand", "arg_fallthrough", "event_handler", "event_type", "msgtypes"]
-        for key in keys:
-            key = f"__mb_{key}__"
-            setattr(new_ch, key, getattr(self, key))
-        return new_ch
+        self.__bound_copies__: Dict[Any, CommandHandler] = {}
+        self.__bound_instance__: Any = None
 
     def __get__(self, instance, instancetype):
+        if not instance or self.__bound_instance__:
+            return self
         try:
-            return self.__instance_vars[instance]
+            return self.__bound_copies__[instance]
         except KeyError:
-            copy = self.__copy__()
-            copy.__class_instance = instance
-            self.__instance_vars[instance] = copy
-            return copy
+            new_ch = type(self)(self.__mb_func__)
+            keys = ["parent", "subcommands", "arguments", "help", "get_name", "is_command_match",
+                    "require_subcommand", "arg_fallthrough", "event_handler", "event_type",
+                    "msgtypes"]
+            for key in keys:
+                key = f"__mb_{key}__"
+                setattr(new_ch, key, getattr(self, key))
+            new_ch.__bound_instance__ = instance
+            new_ch.__mb_subcommands__ = [subcmd.__get__(instance, instancetype)
+                                         for subcmd in self.__mb_subcommands__]
+            self.__bound_copies__[instance] = new_ch
+            return new_ch
 
     @staticmethod
     def __command_match_unset(self, val: str) -> str:
@@ -108,15 +109,15 @@ class CommandHandler:
                 await evt.reply(self.__mb_full_help__)
                 return
 
-        if self.__class_instance:
-            return await self.__mb_func__(self.__class_instance, evt, **call_args)
+        if self.__bound_instance__:
+            return await self.__mb_func__(self.__bound_instance__, evt, **call_args)
         return await self.__mb_func__(evt, **call_args)
 
     async def __call_subcommand__(self, evt: MaubotMessageEvent, call_args: Dict[str, Any],
                                   remaining_val: str) -> Tuple[bool, Any]:
         command, remaining_val = _split_in_two(remaining_val.strip(), " ")
         for subcommand in self.__mb_subcommands__:
-            if subcommand.__mb_is_command_match__(subcommand.__class_instance, command):
+            if subcommand.__mb_is_command_match__(subcommand.__bound_instance__, command):
                 return True, await subcommand(evt, _existing_args=call_args,
                                               remaining_val=remaining_val)
         return False, None
@@ -156,7 +157,7 @@ class CommandHandler:
 
     @property
     def __mb_name__(self) -> str:
-        return self.__mb_get_name__(self.__class_instance)
+        return self.__mb_get_name__(self.__bound_instance__)
 
     @property
     def __mb_prefix__(self) -> str:
diff --git a/maubot/plugin_base.py b/maubot/plugin_base.py
index c720cc5..fbc7891 100644
--- a/maubot/plugin_base.py
+++ b/maubot/plugin_base.py
@@ -23,7 +23,6 @@ from sqlalchemy.engine.base import Engine
 from aiohttp import ClientSession
 
 if TYPE_CHECKING:
-    from mautrix.types import Event
     from mautrix.util.config import BaseProxyConfig
     from .client import MaubotMatrixClient