The cross-process update lock (fe8e4d93d) made the in-progress marker
mutually exclusive across every update entrypoint — but the Tauri
updater holds that marker for its WHOLE run and then spawns
hermes update as a child stage. The child read the marker, found its
own parent's live pid, refused with exit 2, and the GUI mapped that to
"Hermes is still running. Close all Hermes windows and try the update
again." Retry spawns a fresh updater that deadlocks against itself the
same way, so every GUI-driven update dead-ends on the failure screen
with no winnable retry (observed: three consecutive self-refusals in
bootstrap-installer.log within 90 seconds).
Hand the claim off explicitly: update_child_env exports
HERMES_UPDATE_HANDOFF_PID naming the updater's own pid, and
UpdateLock.acquire treats a live holder matching that pid as the lock
we are already running under — run without claiming, and release
leaves the parent's marker untouched. The env var alone grants
nothing: the pid must also be the live marker owner, so a stale or
forged value cannot bypass the lock, and a dashboard-spawned
hermes update (no handoff env) is still refused exactly as before.
The Windows-footgun linter caught a real bug in the new update lock. On
Windows os.kill(pid, 0) is not a no-op: CPython routes sig=0 to
GenerateConsoleCtrlEvent, which sends Ctrl+C to the target's entire
console process group (bpo-14484). The liveness probe would have killed
the very updater it was asking about -- and any sibling sharing that
console.
Delegate to gateway.status._pid_exists, the project's existing no-kill
probe, which uses psutil (OpenProcess/GetExitCodeProcess on Windows) and
also reports zombies as dead. Any pid we cannot evaluate still counts as
dead so a corrupt marker cannot wedge the lock.
Three surfaces start updates against one checkout: a terminal
"hermes update", the dashboard's Update button (which spawns that same
command detached), and the desktop's, which hands off to the Tauri
updater. Only the Tauri updater published the in-progress marker, and
only Electron read it -- to gate backend startup, not to stop a second
updater. So a dashboard-spawned update and an installer-driven git
checkout could mutate the same tree concurrently, rewriting source under
a live interpreter.
Claim the same marker from cmd_update rather than adding a second
mechanism: same path, same pid+started_at payload the Rust and Electron
readers already parse. A marker only counts as live when its pid is alive
and it is inside the shared age ceiling, so a crashed updater self-heals
instead of wedging every future update. Release only removes a marker we
still own, leaving a handoff partner's claim intact.
Refusing exits 2, matching the existing concurrent-instance contract the
Tauri updater already recognizes.
