Sessions now survive `hermes gateway stop` / `restart` on native Windows.
Previously the gateway died on schtasks `/End` + os.kill SIGTERM without
ever running the drain loop, so the v0.13.0 session-resume feature (#21192)
silently broke on Windows: `resume_pending=True` was never written, and
the next boot started with a blank conversation history (issue #33778).
Root cause is twofold and the reporter only identified half of it:
1. `hermes_cli/gateway_windows.py::stop()` did not write the
`planned_stop_marker` before signalling. The reporter caught this.
2. The bigger reason: `asyncio.add_signal_handler` raises
NotImplementedError for SIGTERM/SIGINT on Windows, so even if the
marker had been written, the gateway's existing SIGTERM handler
(which is what calls `runner.stop()` and the `mark_resume_pending`
loop) was never invoked. Writing the marker would have been
necessary-but-insufficient.
The fix has two parts:
* gateway/run.py: new `_run_planned_stop_watcher` daemon thread polls
for the planned-stop marker file every 0.5s. When the marker appears
it `loop.call_soon_threadsafe(shutdown_signal_handler, None)` — the
same shutdown path a real SIGTERM would have driven, including the
pre-drain `mark_resume_pending` writes (run.py:5977) and graceful
drain wait. The existing signal handler already accepts
`received_signal=None` and falls through to
`consume_planned_stop_marker_for_self()`, so no handler changes
needed. Runs on every platform as cheap belt-and-suspenders.
* hermes_cli/gateway_windows.py: `stop()` now writes the marker for
the running gateway PID and waits up to `agent.restart_drain_timeout`
(default 30s) for the PID to exit cleanly. On clean drain, the kill
sweep is non-forceful; on timeout, escalates to
`kill_gateway_processes(force=True)` which routes to taskkill /T /F
per `references/windows-native-support.md`.
Validation:
* 7 new tests in tests/gateway/test_planned_stop_watcher.py covering:
marker→handler dispatch, no-marker idle, already-draining skip,
not-yet-running skip, stop_event responsiveness, fire-once
semantics, error tolerance.
* 8 new tests in tests/hermes_cli/test_gateway_windows.py covering:
marker-before-kill ordering, clean-drain skips force-kill,
drain-timeout escalates to force=True, no-pid-skips-drain,
invalid-pid handling, fast-exit success, timeout failure,
marker-write-failure tolerance.
* E2E (Linux, detached orphan): write_planned_stop_marker(pid) +
`_drain_gateway_pid(pid, 5.0)` returns True in 0.5s after the
victim sees the marker and exits. Tested with a double-forked
subprocess so the test parent isn't holding it as a zombie.
* Targeted: tests/gateway/{restart_drain,restart_resume_pending,
signal,signal_format,status,shutdown_forensics,approve_deny_commands,
planned_stop_watcher} + tests/hermes_cli/{gateway_windows,
gateway_service} → 519/519.
What was wrong with the reporter's claim (for future archaeology): they
described the symptom as "no `resume_pending=True` written to
`sessions.json`" — but Hermes uses `state.db` (SQLite), not
`sessions.json`, and `mark_resume_pending` is called regardless of
the marker (the marker only affects exit code 0 vs 1 for systemd
revival semantics). The real session-loss path is the missing drain
on Windows, not a missing marker. Both halves are fixed here.
Closes#33778.
