使用discord.py Cogs时出现CommandNotFound错误及协程未等待警告

问题根源 #

1. 异步方法未被await：discord.py 2.0+ 中load_extension和add_cog都是异步方法，你的代码直接调用未加await，导致Cogs根本没被加载，所以!hi命令不存在。
2. Cog监听器缺少self参数：on_member_join作为类成员方法，必须以self作为第一个参数，否则后续用户加入时会触发错误。

修复步骤 #

1. 修改主程序代码（正确加载Cogs） #

将加载扩展的逻辑放到异步上下文里，比如在on_ready事件中执行：

import discord
from discord.ext import commands
import os

TOKEN = 'my_token'

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

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

@client.event
async def on_ready():
    await client.change_presence(status=discord.Status.online, activity=discord.Activity(type=discord.ActivityType.watching, name='a server'))
    print('We have Logged in as {0.user}'.format(client))
    # 异步加载所有Cogs
    for filename in os.listdir('./cogs'):
        if filename.endswith('.py'):
            await client.load_extension(f"cogs.{filename[:-3]}")

client.run(TOKEN)

2. 修复Cogs代码 #

• 给on_member_join添加self参数
• setup函数里的add_cog加上await
• 移除过时的pass_context=True

import discord
from discord.ext import commands

rules = ['Users must obey the discord community guidelines.',
         'No racism/homophobia/bullying/etc of any kind Bullying of any kind will end in a mute and possibly a ban.',
         'Everyone Can Report', 'No Server Raiding', 'No Chatting In welcome channel',
         'No robbing and bankrob is illegal', 'No impersonating']

class Greetings(commands.Cog):

    def __init__(self, client):
        self.client = client
    
    @commands.Cog.listener()
    async def on_member_join(self, member):
        await member.send("Hi there, welcome to the server.")
        await member.send("These are the rules:")
        # 用enumerate简化遍历
        for idx, rule in enumerate(rules):
            await member.send(f'RULE {idx+1}: {rule}')

    @commands.command()
    async def hi(self, ctx):
        await ctx.send("hi!")

async def setup(client):
    await client.add_cog(Greetings(client))

额外提示 #

• 新版本discord.py中，pass_context=True已经被废弃，无需再声明
• 使用enumerate遍历序列比range(len())更符合Python风格
• 确保你的discord.py版本是2.x，可通过pip install -U discord.py更新

内容的提问来源于stack exchange，提问作者SanjaySK