Discord.py v2自定义Help Command Cog加载失败问题求助

你的HelpCommand类继承自commands.HelpCommand而非commands.Cog，却使用了仅适用于Cog的@commands.Cog.listener()装饰器，同时discord.py v2对扩展（Cog）的校验更严格，要求扩展必须是commands.Cog子类或通过合法的setup函数配置，这直接导致该模块无法被正常加载。

有两种可行的修正方式，任选其一即可：

方式1：调整HelpCommand结构，移除Cog相关装饰器 #

修改HelpCommand.py代码，移除无效的listener装饰器，并将加载提示移至setup函数中：

import discord
from discord.ext import commands

class CustomHelpCommand(commands.HelpCommand):
    colour = 0x0dd2ff

    def footer(self):
        return f"{self.clean_prefix}{self.invoked_with} [command] for more information"

    def get_command_signature(self, command):
        return f"```\{self.clean_prefix}{command.qualified_name} {command.signature}```"

    async def send_cog_help(self, cog):
        embed = discord.Embed(title=f"**{cog.qualified_name}** commands", colour=self.colour)
        if cog.description:
            embed.description = cog.description

        filtered = await self.filter_commands(cog.get_commands(), sort=True)
        for command in filtered:
            embed.add_field(name=command.qualified_name, value=command.short_doc or "No description")

        embed.set_footer(text=self.footer())
        await self.get_destination().send(embed=embed)

    async def send_command_help(self, command):
        embed = discord.Embed(title=command.qualified_name, colour=self.colour)
        if command.help:
            embed.description = command.help
        embed.add_field(name="Signature", value=self.get_command_signature(command))
        embed.set_footer(text=self.footer())

        await self.get_destination().send(embed=embed)

    async def send_bot_help(self, mapping):
        embed = discord.Embed(title="Bot Commands", colour=self.colour)
        description = self.context.bot.description
        if description:
            embed.description = description

        for cog, commands_list in mapping.items():
            if not cog:
                continue
            filtered = await self.filter_commands(commands_list, sort=True)
            if filtered:
                # 仅显示用户有权限访问的命令
                value = "\t".join(f"`{i.name}`" for i in filtered)
                embed.add_field(name=cog.qualified_name, value=value)

        embed.set_footer(text=self.footer())
        await self.get_destination().send(embed=embed)

async def setup(bot):
    bot.help_command = CustomHelpCommand()
    print("Cog loaded - HelpCommand.py")

方式2：将HelpCommand包装入Cog类（更规范） #

把自定义HelpCommand封装到Cog中，符合discord.py v2的扩展规范，同时支持卸载时恢复原help命令：

import discord
from discord.ext import commands

class HelpCog(commands.Cog):
    def __init__(self, bot):
        self.bot = bot
        # 保存原help命令，卸载时恢复
        self._original_help = bot.help_command
        bot.help_command = CustomHelpCommand()
        bot.help_command.cog = self

    def cog_unload(self):
        self.bot.help_command = self._original_help

class CustomHelpCommand(commands.HelpCommand):
    colour = 0x0dd2ff

    def footer(self):
        return f"{self.clean_prefix}{self.invoked_with} [command] for more information"

    def get_command_signature(self, command):
        return f"```\{self.clean_prefix}{command.qualified_name} {command.signature}```"

    async def send_cog_help(self, cog):
        embed = discord.Embed(title=f"**{cog.qualified_name}** commands", colour=self.colour)
        if cog.description:
            embed.description = cog.description

        filtered = await self.filter_commands(cog.get_commands(), sort=True)
        for command in filtered:
            embed.add_field(name=command.qualified_name, value=command.short_doc or "No description")

        embed.set_footer(text=self.footer())
        await self.get_destination().send(embed=embed)

    async def send_command_help(self, command):
        embed = discord.Embed(title=command.qualified_name, colour=self.colour)
        if command.help:
            embed.description = command.help
        embed.add_field(name="Signature", value=self.get_command_signature(command))
        embed.set_footer(text=self.footer())

        await self.get_destination().send(embed=embed)

    async def send_bot_help(self, mapping):
        embed = discord.Embed(title="Bot Commands", colour=self.colour)
        description = self.context.bot.description
        if description:
            embed.description = description

        for cog, commands_list in mapping.items():
            if not cog:
                continue
            filtered = await self.filter_commands(commands_list, sort=True)
            if filtered:
                value = "\t".join(f"`{i.name}`" for i in filtered)
                embed.add_field(name=cog.qualified_name, value=value)

        embed.set_footer(text=self.footer())
        await self.get_destination().send(embed=embed)

async def setup(bot):
    await bot.add_cog(HelpCog(bot))
    print("Cog loaded - HelpCommand.py")

• 两种方式都能解决加载问题，方式2更符合discord.py v2的设计规范，支持Cog的卸载逻辑；
• 修正了send_bot_help方法中使用未过滤命令的问题，确保只显示用户有权限访问的命令；
• 原代码中的@commands.Cog.listener()装饰器是无效的，因为commands.HelpCommand不是Cog子类，无法监听事件，加载提示直接放在setup函数中即可。

内容的提问来源于stack exchange，提问作者Sierra