"RuntimeWarning: coroutine 'BotBase.load_extension' was never awaited" after upd-CodePudding

The discord bot I made a year ago and deployed to Heroku has worked until now. However, after changing some cogs and updating python to version 3.9.10, I get the following warning in the Heroku logs:

app[worker.1]: /app/m_bot.py:120: RuntimeWarning: coroutine 'BotBase.load_extension' was never awaited
app[worker.1]: client.load_extension(f"cogs.{filename[:-3]}")
app[worker.1]: RuntimeWarning: Enable tracemalloc to get the object allocation traceback
app[worker.1]: Bot is ready.
app[api]: Build succeeded>

The 120 line block is:

for filename in os.listdir("./cogs"):
    if filename.endswith(".py"):
        # cut of the .py from the file name
        client.load_extension(f"cogs.{filename[:-3]}")

The bot goes online but doesn't respond to any command. I haven't made any other changes apart from what was listed above.

It works when I run my bot on my PC, so I suspect it might be a version problem.

How can I resolve this?

CodePudding user response：

Explanation

As of discord.py version 2.0, Bot.load_extension is now a coroutine and has to be awaited. This is to allow Cog subclasses to override cog_unload with a coroutine.

Code

In your client's file:

async def load_extensions():
    for filename in os.listdir("./cogs"):
        if filename.endswith(".py"):
            # cut off the .py from the file name
            await client.load_extension(f"cogs.{filename[:-3]}")

You should also wrap your login in an asynchronous 'main' function, where you would call this function:

async def main():
    async with client:
        await load_extensions()
        await client.start('your_token')

asyncio.run(main())

These two functions replace the old way:

client.run("your_token")

along with the code you posted in your question.

In each of your cogs:

Replace the standard setup function with an asynchronous one:

async def setup(bot):
    await bot.add_cog(YourCog(bot))

Reference

discord.py 2.0 async changes (Thank you ChrisDewa for mentioning this in your comment)