zulip/zerver/lib/async_utils.py

import asyncio

from typing_extensions import override


class NoAutoCreateEventLoopPolicy(asyncio.DefaultEventLoopPolicy):
    """
    By default asyncio.get_event_loop() automatically creates an event
    loop for the main thread if one isn't currently installed.  Since
    Django intentionally uninstalls the event loop within
    sync_to_async, that autocreation proliferates confusing extra
    event loops that will never be run.  It is also deprecated in
    Python 3.10.  This policy disables it so we don't rely on it by
    accident.
    """

    @override
    def get_event_loop(self) -> asyncio.AbstractEventLoop:  # nocoverage
        return asyncio.get_running_loop()