A start-marker probe failure (Get-Process timing out on a PowerShell 5.1
cold start, #87169) in claimBackendChild used to stop the freshly spawned
backend and rethrow — killing a healthy backend, triggering the renderer's
repair respawn, and looping. And because stderr piping only attached after
the claim, every before-ready failure surfaced as a bare exit code.
- extract probe + claim policy into electron/backend-claim.ts:
processStartMarker/execText (moved verbatim from main.ts), probeStartMarker,
and a pure claimDecision(childAlive, probe) a Windows CI lane can drive
with real PowerShell
- probe failure + LIVE child now degrades to PID-only identity
(pid-only:<pid> marker, WARNING logged), matching the existing
createParentStartMarkerResolver degrade pattern; processIdentityMatches
verifies degraded identities by PID liveness (command check still layers
on top in backendIdentityMatches)
- probe failure + DEAD child keeps the fail-closed throw, now carrying the
child's buffered stderr/stdout tail
- ring-buffered ~8KB output tail attached at spawn time in BOTH spawn paths
(pool + primary); tail appended to claim errors, before-ready exit
messages, and backend-ready's exited-before-port-announcement errors so
the real exit reason reaches desktop.log and the boot UI
- tests: claimDecision matrix (degrade test fails against the old
stop+throw behavior), real processStartMarker probe, ring-buffer caps,
and output-tail suffixes on backend-ready exit errors
hermes-seaeye[bot]