asyncio holds only a weak reference to tasks returned by
``create_task``. Fire-and-forget callers that discard the return value
let the event loop GC the task before it finishes, logging
``Task was destroyed but it is pending!`` with no traceback. The #1648
support-bundle review surfaced 94 such warnings in 8 days of v0.2.4.5
-- the silently-vanished exceptions reach support bundles as opaque
GC notices instead of actionable errors.
New backend/app/core/tasks.py::spawn_background_task(coro, *, name=None)
is the one place in the codebase that calls asyncio.create_task. It
stores the task in a module-level set, attaches a done-callback that
auto-removes on completion AND surfaces any uncaught exception via the
logger with the originating traceback, and accepts name= so a leak
source is traceable through /tracebacks and the log line. Cancelled
tasks don't log (a shutting-down service is not an error).
Migrated the 16 truly-orphan create_task call sites to the helper:
main.py (8):
reconcile-stale, cooldown-poweroff, energy calc, smart-plug,
maintenance-check, photo-then-notify, layer-timelapse,
scan-timelapse, print-scheduler, notify-no-archive (the last one
was hand-rolling the same pattern with task + no-op done_callback)
printers.py:3123 apply-pa-after-refresh
print_queue.py:1034 queue cooldown-poweroff
firmware_update.py:261 firmware upload
archive.py:1514 timelapse mp4 convert
print_scheduler.py:2199 watchdog print-start
library.py:1614 STL backfill
smart_plugs.py:259 tasmota scan
discovery.py:159 subnet scan
smart_plug_manager.py x3 plug auto-off-pending
background_dispatch.py x2 (lambda-wrapped inside
loop.call_soon_threadsafe) upload progress
Sites that already kept strong refs are unchanged:
self._tasks.append(asyncio.create_task(...)) -- VP manager,
tcp_proxy, mqtt_server
self._x_task = asyncio.create_task(...) on service instances --
mqtt_bridge, obico_detection, github_backup, archive_purge,
local_backup, library_trash, discovery service
Locally assigned + awaited/gathered -- tcp_proxy bidirectional
pumps, camera_fanout, slice_dispatch, slicer_api progress_task,
manager._finish_release_task, main.py module-level cleanup loops
maziggy
f243e4e598