Issues with loading cogs in a Python Discord bot and runtime warnings

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1

I’m new to developing Discord bots using Python and I’m facing some challenges when trying to load cogs. Everything works fine in a single file, but I encounter runtime warnings as soon as I implement cogs.

main.py

import discord
import os
from discord.ext import commands
from dotenv import load_dotenv

load_dotenv()
token = os.getenv('TOKEN')

intents = discord.Intents.default()
intents.messages = True
intents.message_content = True

bot = commands.Bot(command_prefix='!', intents=intents)

@bot.event
async def on_ready():
    print("Bot is up and ready!")

@bot.command()
async def load_cog(ctx, cog_name):
    try:
        bot.load_extension(f'cogs.{cog_name}')
        await ctx.send(f'Cog {cog_name} has been loaded.')
    except Exception as e:
        await ctx.send(f'Error loading cog: {e}')

if __name__ == "__main__":
    for filename in os.listdir('./cogs'):
        if filename.endswith('.py'):
            bot.load_extension(f'cogs.{filename[:-3]}')

    bot.run(token)

cogs/sample_game.py

from discord.ext import commands
import random

class SampleGame(commands.Cog):
    def __init__(self, bot):
        self.bot = bot

    @commands.command()
    async def start_game(self, ctx):
        # Game logic goes here
        pass

def setup(bot):
    bot.add_cog(SampleGame(bot))

I’m getting runtime warnings that I can’t resolve:

RuntimeWarning: coroutine 'BotBase.load_extension' was never awaited
  bot.load_extension(f'cogs.{filename[:-3]}')
RuntimeWarning: Enable tracemalloc to get the object allocation traceback

What am I doing incorrectly with the cog implementation? The bot connects successfully, but these warnings are concerning me.

2

You’re mixing sync and async code. The main issue is calling bot.load_extension synchronously before the bot runs, but newer discord.py versions need you to await it. I hit this same problem migrating an older bot. Don’t load cogs in the main block - create an async function that loads all extensions and call it from on_ready. You could use asyncio.run() before starting the bot, but on_ready is cleaner since it waits for full initialization. The tracemalloc warning is just Python suggesting memory debugging tools for the coroutine mess.

3

Those runtime warnings stem from the changes in discord.py versions. In version 2.0 and above, the method load_extension is now asynchronous, which means it should be awaited. You should move your cog loading logic into the on_ready event so that you can properly use await with bot.load_extension. This adjustment resolves the warnings and allows for better error handling as well since it enables you to manage load failures without crashing the bot. I faced a similar issue during my own upgrade and it took me a while to pinpoint this change.

4

Same thing happened when I upgraded discord.py. Easy fix - wrap your cog loading in an async setup function and call it with asyncio.run() before bot.run(). Like async def load_cogs(): await bot.load_extension(...) then asyncio.run(load_cogs()) in your main block. Works perfectly.