Replace fire_coroutine_threadsafe with asyncio.run_coroutine_threadsafe (#88572)

fire_coroutine_threadsafe did not hold a reference to the asyncio
task which meant the task had the risk of being prematurely
garbage collected

homeassistant/core.py

@@ -14,6 +14,7 @@ from collections.abc import (
     Iterable,
     Mapping,
 )
+import concurrent.futures
 from contextlib import suppress
 from contextvars import ContextVar
 import datetime
@@ -79,11 +80,7 @@ from .exceptions import (
 )
 from .helpers.aiohttp_compat import restore_original_aiohttp_cancel_behavior
 from .util import dt as dt_util, location, ulid as ulid_util
-from .util.async_ import (
+from .util.async_ import run_callback_threadsafe, shutdown_run_callback_threadsafe
-    fire_coroutine_threadsafe,
-    run_callback_threadsafe,
-    shutdown_run_callback_threadsafe,
-)
 from .util.read_only_dict import ReadOnlyDict
 from .util.timeout import TimeoutManager
 from .util.unit_system import (
@@ -294,6 +291,7 @@ class HomeAssistant:
         self._stopped: asyncio.Event | None = None
         # Timeout handler for Core/Helper namespace
         self.timeout: TimeoutManager = TimeoutManager()
+        self._stop_future: concurrent.futures.Future[None] | None = None
 
     @property
     def is_running(self) -> bool:
@@ -312,12 +310,14 @@ class HomeAssistant:
         For regular use, use "await hass.run()".
         """
         # Register the async start
-        fire_coroutine_threadsafe(self.async_start(), self.loop)
+        _future = asyncio.run_coroutine_threadsafe(self.async_start(), self.loop)
-
         # Run forever
         # Block until stopped
         _LOGGER.info("Starting Home Assistant core loop")
         self.loop.run_forever()
+        # The future is never retrieved but we still hold a reference to it
+        # to prevent the task from being garbage collected prematurely.
+        del _future
         return self.exit_code
 
     async def async_run(self, *, attach_signals: bool = True) -> int:
@@ -682,7 +682,11 @@ class HomeAssistant:
         """Stop Home Assistant and shuts down all threads."""
         if self.state == CoreState.not_running:  # just ignore
             return
-        fire_coroutine_threadsafe(self.async_stop(), self.loop)
+        # The future is never retrieved, and we only hold a reference
+        # to it to prevent it from being garbage collected.
+        self._stop_future = asyncio.run_coroutine_threadsafe(
+            self.async_stop(), self.loop
+        )
 
     async def async_stop(self, exit_code: int = 0, *, force: bool = False) -> None:
         """Stop Home Assistant and shuts down all threads.

homeassistant/util/async_.py

@@ -1,9 +1,9 @@
 """Asyncio utilities."""
 from __future__ import annotations
 
-from asyncio import Semaphore, coroutines, ensure_future, gather, get_running_loop
+from asyncio import Semaphore, gather, get_running_loop
 from asyncio.events import AbstractEventLoop
-from collections.abc import Awaitable, Callable, Coroutine
+from collections.abc import Awaitable, Callable
 import concurrent.futures
 import functools
 import logging
@@ -20,29 +20,6 @@ _R = TypeVar("_R")
 _P = ParamSpec("_P")
 
 
-def fire_coroutine_threadsafe(
-    coro: Coroutine[Any, Any, Any], loop: AbstractEventLoop
-) -> None:
-    """Submit a coroutine object to a given event loop.
-
-    This method does not provide a way to retrieve the result and
-    is intended for fire-and-forget use. This reduces the
-    work involved to fire the function on the loop.
-    """
-    ident = loop.__dict__.get("_thread_ident")
-    if ident is not None and ident == threading.get_ident():
-        raise RuntimeError("Cannot be called from within the event loop")
-
-    if not coroutines.iscoroutine(coro):
-        raise TypeError(f"A coroutine object is required: {coro}")
-
-    def callback() -> None:
-        """Handle the firing of a coroutine."""
-        ensure_future(coro, loop=loop)
-
-    loop.call_soon_threadsafe(callback)
-
-
 def run_callback_threadsafe(
     loop: AbstractEventLoop, callback: Callable[..., _T], *args: Any
 ) -> concurrent.futures.Future[_T]:

tests/util/test_async.py

@@ -10,43 +10,6 @@ from homeassistant.core import HomeAssistant
 from homeassistant.util import async_ as hasync
 
 
-@patch("asyncio.coroutines.iscoroutine")
-@patch("concurrent.futures.Future")
-@patch("threading.get_ident")
-def test_fire_coroutine_threadsafe_from_inside_event_loop(
-    mock_ident, _, mock_iscoroutine
-) -> None:
-    """Testing calling fire_coroutine_threadsafe from inside an event loop."""
-    coro = MagicMock()
-    loop = MagicMock()
-
-    loop._thread_ident = None
-    mock_ident.return_value = 5
-    mock_iscoroutine.return_value = True
-    hasync.fire_coroutine_threadsafe(coro, loop)
-    assert len(loop.call_soon_threadsafe.mock_calls) == 1
-
-    loop._thread_ident = 5
-    mock_ident.return_value = 5
-    mock_iscoroutine.return_value = True
-    with pytest.raises(RuntimeError):
-        hasync.fire_coroutine_threadsafe(coro, loop)
-    assert len(loop.call_soon_threadsafe.mock_calls) == 1
-
-    loop._thread_ident = 1
-    mock_ident.return_value = 5
-    mock_iscoroutine.return_value = False
-    with pytest.raises(TypeError):
-        hasync.fire_coroutine_threadsafe(coro, loop)
-    assert len(loop.call_soon_threadsafe.mock_calls) == 1
-
-    loop._thread_ident = 1
-    mock_ident.return_value = 5
-    mock_iscoroutine.return_value = True
-    hasync.fire_coroutine_threadsafe(coro, loop)
-    assert len(loop.call_soon_threadsafe.mock_calls) == 2
-
-
 @patch("concurrent.futures.Future")
 @patch("threading.get_ident")
 def test_run_callback_threadsafe_from_inside_event_loop(mock_ident, _) -> None: