fix: guard connection-state callbacks against no running event loop

The previous hotfix's disconnect()-on-comm-error path can now fire
during server/brewpi.py's own final best-effort hardware-release
cleanup (finally: block's heater.close()/stirrer.activate(False)),
which runs after the event loop has already stopped - previously
nothing about hardware teardown touched an AttributeChange-tracked
field, so this path was dormant. asyncio.create_task() there raises
RuntimeError: no running event loop, crashing the shutdown sequence.

Adds fire_and_forget() (tasks/task.py) - asyncio.create_task() that
silently drops the message instead of raising when there's no loop to
schedule on - and uses it for the Connected/FirmwareVersion broadcasts.
SudTask.check_connections() also now no-ops entirely without a running
loop, since self.sud.stop() cascades into further unguarded
create_task() calls (on_state_changed, heater_task.shutdown(), ...)
that a stopped loop can't help with anyway.

Reproduced and verified fixed directly against HeaterTask/HeaterHendi
with no event loop running (mirrors the exact server/brewpi.py
shutdown-time call path that crashed on the brewpi Pi).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YaPLuRPpyjWcwhMvCvpHCL

tasks/__init__.py

@@ -1,4 +1,4 @@
-from tasks.task import ATask, TaskManager
+from tasks.task import ATask, TaskManager, fire_and_forget
 from tasks.tempsensor import TempSensorTask
 from tasks.heater import HeaterTask
 from tasks.stirrer import StirrerTask

tasks/heater.py

@@ -1,5 +1,5 @@
 import asyncio
-from tasks import ATask
+from tasks import ATask, fire_and_forget
 from components import AHeater
 from ws.message import MsgIo
 from utils.value import ChangedInteger
@@ -34,12 +34,12 @@ class HeaterTask(ATask):
 		self._on_connected_changed = callback
 
 	def on_connected_changed(self, value):
-		asyncio.create_task(self.send({'Connected': value}))
+		fire_and_forget(self.send({'Connected': value}))
 		if self._on_connected_changed:
 			self._on_connected_changed(value)
 
 	def on_firmware_version_changed(self, value):
-		asyncio.create_task(self.send({'FirmwareVersion': value}))
+		fire_and_forget(self.send({'FirmwareVersion': value}))
 
 	def shutdown(self):
 		"""Called when the brew ends (DONE/IDLE). Switches to open-loop at

tasks/stirrer.py

@@ -1,5 +1,5 @@
 import asyncio
-from tasks import ATask
+from tasks import ATask, fire_and_forget
 from ws.message import MsgIo
 from components import AStirrer
 from utils.value import ChangedInteger
@@ -34,12 +34,12 @@ class StirrerTask(ATask):
 		self._on_connected_changed = callback
 
 	def on_connected_changed(self, value):
-		asyncio.create_task(self.send({'Connected': value}))
+		fire_and_forget(self.send({'Connected': value}))
 		if self._on_connected_changed:
 			self._on_connected_changed(value)
 
 	def on_firmware_version_changed(self, value):
-		asyncio.create_task(self.send({'FirmwareVersion': value}))
+		fire_and_forget(self.send({'FirmwareVersion': value}))
 
 	async def recv(self, data):
 		for pair in data.items():

tasks/sud.py

@@ -1,6 +1,6 @@
 import asyncio
 import bisect
-from tasks import ATask
+from tasks import ATask, fire_and_forget
 from ws.message import MsgIo
 from utils.value import ChangedFloat
 from components import APid, AStirrer, AHeater
@@ -265,14 +265,28 @@ class SudTask(ATask):
 		outside RAMPING/HOLDING/WAIT_USER/PAUSED), the same path a manual
 		Stop press takes, so all the usual shutdown plumbing (heater
 		shutdown, sud log stop_run - see SudTask.set_on_end()'s wiring in
-		server/brewpi.py) fires exactly as it would for Stop."""
+		server/brewpi.py) fires exactly as it would for Stop.
+
+		No-op if there's no running event loop - happens when a
+		Connectable's connected attribute changes as a side effect of the
+		server's own final best-effort hardware-release cleanup
+		(server/brewpi.py's `finally:` block), which runs after the loop
+		has already stopped. self.sud.stop() below cascades into Sud's own
+		'state' observable (on_state_changed -> heater_task.shutdown()/
+		sud_log_task.stop_run()), which isn't itself guarded against a
+		stopped loop - the whole server is already tearing down at that
+		point regardless, so there's nothing useful to stop/notify."""
+		try:
+			asyncio.get_running_loop()
+		except RuntimeError:
+			return
 		if self.sud.state in (SudState.IDLE, SudState.DONE):
 			return
 		if self.heater.connected and self.stirrer.connected:
 			return
 		self.sud.stop()
-		asyncio.create_task(self.send({'Error': 'Heater/Stirrer disconnected - brew stopped.'}))
-		asyncio.create_task(self.send({'Error': None}))
+		fire_and_forget(self.send({'Error': 'Heater/Stirrer disconnected - brew stopped.'}))
+		fire_and_forget(self.send({'Error': None}))
 
 	def on_state_changed(self, value):
 		asyncio.create_task(self.send({'State': str(value)}))

tasks/task.py

@@ -3,6 +3,21 @@ import asyncio
 from utils.value import AttributeChange
 
 
+def fire_and_forget(coro):
+	"""asyncio.create_task(), tolerant of there being no running event loop.
+	An actor's observable attribute (e.g. Connectable.connected) can change
+	as a side effect of the server's own final best-effort hardware-release
+	cleanup (server/brewpi.py's `finally:` block - heater.close()/
+	stirrer.activate(False)), which runs after the loop has already
+	stopped. There's nobody left to notify at that point anyway, so this
+	just drops the message instead of crashing the shutdown sequence."""
+	try:
+		return asyncio.create_task(coro)
+	except RuntimeError:
+		coro.close()
+		return None
+
+
 class ATask(AttributeChange):
 	def __init__(self, interval):
 		AttributeChange.__init__(self)