Intermittent message.add_reaction() - 403 Forbidden (error code: 50013)

Summary

Sometimes my bot gets 403 errors when trying to add reactions to messages.

Reproduction Steps

It comes up in my logs sometimes. I haven’t been able to figure out why.

Minimal Reproducible Code

import discord


def bot_can_react(message: discord.Message) -> bool:
    if message.channel.type == discord.ChannelType.private:
        return True
    
    perms = message.channel.guild.me.permissions_in(message.channel)
    
    return (
        perms.read_message_history and 
        perms.read_messages and
        perms.add_reactions and
        perms.manage_messages
    )


class Bot(discord.Client):
    async def on_message(self, message: discord.Message) -> None:
        if bot_can_react(message):
            message.add_reaction("✅")

Expected Results

The bot should react to messages with a ✅ emoji.

Actual Results

99% of the time this seems to work fine. Sometimes I get the 403 error 🤷🏻‍♀️

May 09 14:09:53 app/web.1 [2021-05-09 21:09:53][spellbot.operations][ERROR] - warning: discord (guild 841042902037823498): could not react to message: 403 Forbidden (error code: 50013): Missing Permissions
May 09 14:09:53 app/web.1 Traceback (most recent call last):
May 09 14:09:53 app/web.1   File "/usr/local/lib/python3.9/site-packages/spellbot/operations.py", line 133, in safe_react_emoji
May 09 14:09:53 app/web.1     await message.channel.send(s("reaction_permissions_required"))
May 09 14:09:53 app/web.1   File "/usr/local/lib/python3.9/site-packages/discord/abc.py", line 1065, in send
May 09 14:09:53 app/web.1     data = await state.http.send_message(channel.id, content, tts=tts, embed=embed,
May 09 14:09:53 app/web.1   File "/usr/local/lib/python3.9/site-packages/discord/http.py", line 248, in request
May 09 14:09:53 app/web.1     raise Forbidden(r, data)
May 09 14:09:53 app/web.1 discord.errors.Forbidden: 403 Forbidden (error code: 50013): Missing Permissions

Intents

32511

System Information

• Python v3.8.8-final
• discord.py v1.7.1-final
• aiohttp v3.7.4.post0
• system info: Darwin 20.3.0 Darwin Kernel Version 20.3.0: Thu Jan 21 00:07:06 PST 2021; root:xnu-7195.81.3~1/RELEASE_X86_64

Checklist

• I have searched the open issues for duplicates.
• I have shown the entire traceback, if possible.
• I have removed my token from display, if visible.

Additional Context

My main question is if I have the bot_can_react() function implemented correctly here. If it’s a private channel I just assume that I have the permissions because AFAIK there’s no way to tell? At least, I dug through the documentation and I couldn’t find a way.

Otherwise I use message.channel.guild.me.permissions_in() to ensure that I have all the following permissions:

• read-message-history
• read-messages
• add-reactions
• manage-messages

That should be good, right? Are there other permissions that I need to check here? Is there a way to check permissions for Direct Messages that I’m missing?

I just don’t know why I am seeing 403 errors here. It seems like it shouldn’t be possible.

[Rapptz]

Yeah when this was introduced we library developers were against 400s/403s counting as spam for this reason but the Discord developers thought we were over-exaggerating the issue.

[Rapptz]

Is there some way to know if I am blocked by the user before attempting the add_reaction() call?

Nope.