From 4134a17a29e5e1cf5bd14e83ca260b472aa28a41 Mon Sep 17 00:00:00 2001
From: Sebastian Law <44045823+SebbyLaw@users.noreply.github.com>
Date: Thu, 8 Apr 2021 19:04:10 -0700
Subject: [PATCH] [commands] Raise error when a cog name is already registered
---
discord/ext/commands/bot.py | 24 ++++++++++++++++++++++--
1 file changed, 22 insertions(+), 2 deletions(-)
diff --git a/discord/ext/commands/bot.py b/discord/ext/commands/bot.py
index dabe14398..4ab5ee350 100644
--- a/discord/ext/commands/bot.py
+++ b/discord/ext/commands/bot.py
@@ -489,15 +489,25 @@ class BotBase(GroupMixin):
# cogs
- def add_cog(self, cog):
+ def add_cog(self, cog: Cog, *, override: bool = False) -> None:
"""Adds a "cog" to the bot.
A cog is a class that has its own event listeners and commands.
+ .. versionchanged:: 2.0
+
+ :exc:`.ClientException` is raised when a cog with the same name
+ is already loaded.
+
Parameters
-----------
cog: :class:`.Cog`
The cog to register to the bot.
+ override: :class:`bool`
+ If a previously loaded cog with the same name should be ejected
+ instead of raising an error.
+
+ .. versionadded:: 2.0
Raises
-------
@@ -505,13 +515,23 @@ class BotBase(GroupMixin):
The cog does not inherit from :class:`.Cog`.
CommandError
An error happened during loading.
+ .ClientException
+ A cog with the same name is already loaded.
"""
if not isinstance(cog, Cog):
raise TypeError('cogs must derive from Cog')
+ cog_name = cog.__cog_name__
+ existing = self.__cogs.get(cog_name)
+
+ if existing is not None:
+ if not override:
+ raise discord.ClientException(f'Cog named {cog_name!r} already loaded')
+ self.remove_cog(cog_name)
+
cog = cog._inject(self)
- self.__cogs[cog.__cog_name__] = cog
+ self.__cogs[cog_name] = cog
def get_cog(self, name):
"""Gets the cog instance requested.