Addresses the two follow-up notes from review: document that
pre_restart_pids is a bare PID set (not (pid, start_time) pairs), so a
recycled PID from one gateway landing in another's stale record could
still mislabel it as down; and add a companion test asserting a
matching start_time still yields the live/current row.
collect_fleet_versions()'s gateway_state.json fallback path only checked
_pid_exists(pid) to decide whether a recorded gateway was still running.
On Windows, a paused gateway's PID can be recycled by an unrelated
process spawned during the update's own churn (npm/git/python
subprocesses) before the record is refreshed, so the dead gateway's
stale code_sha still gets compared against HEAD and reported STALE for a
PID that no longer belongs to it (#93258).
Switch to runtime_status_pid_is_live(), the existing (pid, start_time)
PID-reuse guard already used elsewhere in gateway/status.py, so a
recycled PID is treated the same as a dead one (DOWN row, or no row, per
the existing rollout-safety rules) instead of a false STALE.
Phase-1 verification gap (#91277, found auditing our own landed matrix
against the mapped issues): collect_fleet_versions only listed gateways
with a LIVE pid, so 'restart stopped it and nothing came back' produced
NO row at all — the exact silent-failure shape the matrix exists to
catch (#88848/#74973 class) passed with exit 0.
- collect_fleet_versions(pre_restart_pids=...): a dead pid becomes a
'down' row only when it was alive at update start AND its runtime
status still claims a running state. Rollout-safe: no snapshot (old
callers), clean stops, startup failures, and stale records from
long-dead gateways keep the historical no-row behavior.
- print_fleet_version_matrix escalates on down rows like stale ones
(exit 1) with the per-profile restart remediation.
- cmd_update passes its existing pre-restart PID snapshot.
Sabotage-verified (reverting the membership check fails the new test);
live-verified with a real spawned-then-killed process producing the
DOWN row and matrix escalation.
chelsealong