Fix broken cog attribute (#1662)

* fix: broken cog attribute

* chore: improve a cog check

* Fix typehint

* fix: for the fix: for the fix

* fix: for the fix: for the fix: for the fix

* refactor: redundant code

* Fix command.parent in groups

Co-authored-by: BobDotCom <71356958+BobDotCom@users.noreply.github.com>

Author: Middledot

discord/cog.py

@@ -531,6 +531,9 @@ def _inject(self: CogT, bot) -> CogT:
             command._set_cog(self)
 
             if isinstance(command, ApplicationCommand):
+                if isinstance(command, discord.SlashCommandGroup):
+                    for x in command.walk_commands():
+                        x.parent = command
                 bot.add_application_command(command)
 
             elif command.parent is None:

discord/commands/core.py

@@ -686,8 +686,6 @@ def __init__(self, func: Callable, *args, **kwargs) -> None:
         self._before_invoke = None
         self._after_invoke = None
 
-        self._cog = MISSING
-
     def _validate_parameters(self):
         params = self._get_signature_parameters()
         if kwop := self.options:
@@ -810,7 +808,7 @@ def _is_typing_optional(self, annotation):
 
     @property
     def cog(self):
-        return self._cog
+        return getattr(self, "_cog", MISSING)
 
     @cog.setter
     def cog(self, val):
@@ -1116,7 +1114,7 @@ def __init__(
 
         self._before_invoke = None
         self._after_invoke = None
-        self.cog = None
+        self.cog = MISSING
         self.id = None
 
         # Permissions
@@ -1160,12 +1158,21 @@ def to_dict(self) -> dict:
 
         return as_dict
 
+    def add_command(self, command: SlashCommand) -> None:
+        # check if subcommand has no cog set
+        # also check if cog is MISSING because it
+        # might not have been set by the cog yet
+        if command.cog is MISSING and self.cog is not MISSING:
+            command.cog = self.cog
+
+        self.subcommands.append(command)
+
     def command(
         self, cls: type[T] = SlashCommand, **kwargs
     ) -> Callable[[Callable], SlashCommand]:
         def wrap(func) -> T:
             command = cls(func, parent=self, **kwargs)
-            self.subcommands.append(command)
+            self.add_command(command)
             return command
 
         return wrap
@@ -1262,7 +1269,7 @@ def inner(cls: type[SlashCommandGroup]) -> SlashCommandGroup:
                 guild_ids=guild_ids,
                 parent=self,
             )
-            self.subcommands.append(group)
+            self.add_command(group)
             return group
 
         return inner

discord/ext/commands/help.py

@@ -384,7 +384,7 @@ def get_bot_mapping(self):
         """Retrieves the bot mapping passed to :meth:`send_bot_help`."""
         bot = self.context.bot
         mapping = {cog: cog.get_commands() for cog in bot.cogs.values()}
-        mapping[None] = [c for c in bot.commands if c.cog is None]
+        mapping[None] = [c for c in bot.commands if not c.cog]
         return mapping
 
     @property