The single-query signal handler in cli.py raises KeyboardInterrupt on
SIGTERM/SIGHUP. For interactive 'hermes chat -q' that unwinds the main
thread cleanly. For kanban workers spawned by the dispatcher, the
worker process is likely to have a non-daemon thread alive (terminal
_wait_for_process, custom plugins, etc.). With KeyboardInterrupt only
the main thread unwinds; the non-daemon thread keeps the process alive,
the gateway has already restarted, and the dispatcher's _pid_alive
check returns True forever — task stuck in 'running' indefinitely.
When HERMES_KANBAN_TASK is set (dispatcher-spawned worker), flush
logging + stdout/stderr, then os._exit(0) instead of raising
KeyboardInterrupt. The kernel reclaims the PID immediately, and the
existing zombie-state detection in _pid_alive flips the task to
crashed on the next dispatcher tick. detect_crashed_workers then
re-spawns it on the following tick — no manual recovery needed.
A SIGALRM(2s) deadman is armed before the flush so a pathological
blocking-I/O flush can't wedge the worker forever. In practice the
reporter measured flush in <1ms; the alarm is a failsafe, never
the common path.
Interactive (non-kanban) chat -q is unchanged — the env-gated branch
only fires for dispatcher-spawned workers.
Live verification on this machine:
- Without HERMES_KANBAN_TASK + non-daemon thread alive: process hangs
alive 4+ seconds after SIGTERM. Dispatcher's _pid_alive returns
True → task stuck.
- With HERMES_KANBAN_TASK + same non-daemon thread: process exits in
0.10s via os._exit(0). Dispatcher reclaims on next tick.
Tests:
- tests/hermes_cli/test_signal_handler_kanban_worker.py (3 cases):
end-to-end subprocess test with a non-daemon thread,
HERMES_KANBAN_TASK env, SIGTERM, dispatcher-style _pid_alive check.
Plus a source-level invariant test catching future refactors that
drop the env-gated exit.
- 452/452 kanban tests pass.
Co-authored-by: andrewhosf <andrewho.sf@gmail.com>
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