fix: avoid premature garbage collection of tasks (#2510)

* avoid premature garbage collection of Client tasks

* style(pre-commit): auto fixes from pre-commit.com hooks

* remove typehint (pre-commit makes it non compatible with older python)

* style(pre-commit): auto fixes from pre-commit.com hooks

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

discord/client.py

@@ -256,6 +256,9 @@ def __init__(
             VoiceClient.warn_nacl = False
             _log.warning("PyNaCl is not installed, voice will NOT be supported")
 
+        # Used to hard-reference tasks so they don't get garbage collected (discarded with done_callbacks)
+        self._tasks = set()
+
     async def __aenter__(self) -> Client:
         loop = asyncio.get_running_loop()
         self.loop = loop
@@ -423,8 +426,12 @@ def _schedule_event(
         **kwargs: Any,
     ) -> asyncio.Task:
         wrapped = self._run_event(coro, event_name, *args, **kwargs)
-        # Schedules the task
-        return asyncio.create_task(wrapped, name=f"pycord: {event_name}")
+
+        # Schedule task and store in set to avoid task garbage collection
+        task = asyncio.create_task(wrapped, name=f"pycord: {event_name}")
+        self._tasks.add(task)
+        task.add_done_callback(self._tasks.discard)
+        return task
 
     def dispatch(self, event: str, *args: Any, **kwargs: Any) -> None:
         _log.debug("Dispatching event %s", event)