IndexError - pop from an empty deque

[Iinksafe]

Summary

The library tries to .popleft() from an empty deque when receiving the READY event.

Reproduction Steps

1. Run the code.
2. Wait for the on_connect function to be dispatched.
3. 2/5 of the time errors with the error in the title (and on_ready will NOT run).

Minimal Reproducible Code

Traceback (most recent call last):
  File "main.py", line 279, in <module>
    asyncio.run(start())
  File "/nix/store/hd4cc9rh83j291r5539hkf6qd8lgiikb-python3-3.10.8/lib/python3.10/asyncio/runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "/nix/store/hd4cc9rh83j291r5539hkf6qd8lgiikb-python3-3.10.8/lib/python3.10/asyncio/base_events.py", line 636, in run_until_complete
    self.run_forever()
  File "/nix/store/hd4cc9rh83j291r5539hkf6qd8lgiikb-python3-3.10.8/lib/python3.10/asyncio/base_events.py", line 603, in run_forever
    self._run_once()
  File "/nix/store/hd4cc9rh83j291r5539hkf6qd8lgiikb-python3-3.10.8/lib/python3.10/asyncio/base_events.py", line 1884, in _run_once
    handle = self._ready.popleft()
IndexError: pop from an empty deque

Expected Results

Actual Results

Intents

message_content, guild_messages, dm_messages, presences, members, emojis, guilds

System Information

• Python v3.10.8-final
• discord.py v2.3.1-final
• aiohttp v3.8.3
• system info: Linux 5.19.0-1027-gcp #.29~22.04.1-Ubuntu SMP Thu Jun 22 05:13:17 UTC 2023

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

I upgraded today to Python 3.10. This wasn't happening in Python 3.8. Maybe we should check whether _ready can be .popleft()ed (i.e., check if it's NOT empty before trying to use .popleft()).

[Iinksafe]

Please note that this only happens 2/5 of the time, not always. So there seems to be a problem with receiving events from the gateway (in specific, the READY payload.)

[Rapptz]

There's nothing in this traceback that points to anything within the library and seems like an asyncio internal issue.

[Iinksafe]

Alright, thanks for the quick response. Closing.