Two situations were silently landing in the "none" answer, which
require_drivable_supervisor accepts and the script then falls back to a raw
kill + nohup — exactly the wrong move when a supervisor actually IS present:
- installed-but-not-loaded, on either supervisor. `systemctl --user is-active`
answers "no" for activating/deactivating/failed and while an auto-restart is
pending too, and every one of those is a host that IS under systemd (or
launchd) and about to act again. `*_installed` already knew this; it was
only ever consulted for a warning line, never by the decision itself.
- a systemd probe that could not answer at all (e.g. systemctl cannot reach
the user bus over a non-lingering ssh session) looked identical to a clean
negative, because both probes redirected stderr straight to /dev/null.
detect_supervisor now returns a fifth answer, "unclear", for both cases.
systemd_loaded/systemd_installed capture systemctl's exit status and stderr
separately and set their own *_ERRORED flag only on a real tool failure
(non-zero exit WITH stderr), never on a clean negative. "none" now means only:
neither supervisor installed, neither loaded, neither probe errored.
require_drivable_supervisor die()s on "unclear" exactly like it already does
on "ambiguous", naming the specific supervisor and reason via the new
SUPERVISOR_UNCLEAR_DETAIL global.
Tests: 4 new cases (systemd/launchd installed-but-not-loaded, a real
systemd_loaded run through a systemctl stub that errors on stderr, and the
die() refusal for "unclear" naming the unit). All 3 new guards were verified
by mutation: each was removed from the real script, the suite caught it (a
new FAIL line naming the exact broken assertion), then the file was restored
byte-identically and the suite went green again.
launchd, systemd --user, and unsupervised are three different answers, not two.
Refuse (die) rather than fall through to kill+nohup when a supervisor is
detected that this script cannot drive (e.g. both signals fire at once), and
add a post-restart check that fails the run if more than one fleetd process
is alive. detect_supervisor()/require_drivable_supervisor()/
count_daemon_pids()/assert_single_daemon() are pure, overridable functions so
scripts/test-redeploy-fleetd.sh can exercise them without a real launchd or
systemd.
Dai Ha