`hermes gateway restart` on macOS never took the graceful path, so every
restart — including deliberate ones — was reported to chat as an unplanned
shutdown.
`launchd_restart()` diverged from `systemd_restart()` in two ways, each
sufficient to break it on its own:
1. Wrong helper. It called `_request_gateway_self_restart()`, which is gated
on `_is_pid_ancestor_of_current_process()`. That holds only when the CLI
was spawned *by* the gateway (in-chat `/restart`). Invoked from a shell the
gateway is a sibling, so the guard returns False and SIGUSR1 is never sent.
`_graceful_restart_via_sigusr1()` — same job, no ancestry gate, already
used by `systemd_restart()` and the updater — had no launchd call site.
2. Wrong budget. It waited `_get_restart_drain_timeout()`, which defaults to
0, so `_wait_for_gateway_exit(timeout=0.0)` could never succeed. The
systemd branch uses `_get_restart_exit_wait_budget()`
(drain + after_turn + 15s headroom); `resolve_restart_exit_wait_budget()`
documents that callers falling back to a hard kill must cover both phases
or they reintroduce #77184.
The result was a bare SIGTERM followed immediately by `kickstart -k`. Since
SIGTERM leaves `restart_requested` False, the gateway exited 1 instead of 75
and announced "⚠️ Gateway shutting down — Your current task will be
interrupted." instead of "restarting", dropping the resume_pending handoff
that lets a session resume after the bounce.
Observed on macOS 27.0 / Hermes 0.20.4:
→ Stopping gateway (PID 49787) — draining in-flight runs (up to 0s)...
⚠ Gateway PID 49787 still running after 0.0s — restart may fail
⚠ Gateway drain timed out after 0s — forcing launchd restart
Send SIGUSR1 with the exit-wait budget and return on success, leaving
launchd's unconditional KeepAlive to revive the process. `kickstart -k` stays
as the fallback for a genuine drain timeout, but must not run after a
successful graceful exit or it would kill the replacement instance.
The wedged-loop escalation (#81642) still short-circuits ahead of this, so a
provably dead event loop is not handed a signal it cannot process.
Tests: adds a launchd counterpart to the existing systemd graceful-restart
test, asserting SIGUSR1 with the exit-wait budget and no bare SIGTERM or
kickstart on success. Updates the three wedged-gateway tests, which asserted
the old SIGTERM-plus-drain shape; they also now stub
`_graceful_restart_via_sigusr1` so no real signal escapes to the fake PID.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Joby Ellington
7a76046a86