Phase 0 hardware characterization showed real mbedTLS/wss client teardown
takes ~5-6s per connected slot, sequentially, so the flat 8s
MQTT_STOP_TIMEOUT_MS force-timed-out healthy multi-slot stops (2-slot
non-PSRAM ~11-12s, 3-slot PSRAM ~16s), which sets the dirty latch and
makes the OTA barrier withhold flashing -- multi-slot nodes could never
ota update.
Replace the flat constant with a slot-scaled budget computed per stop in
end(): 5s base + 8s per enabled slot (~1.5-2x headroom over measured),
applied via new MQTTLifecycle::Coordinator::setStopTimeoutMs() before
requestStop(). Headroom is nearly free: end() returns as soon as the task
acks (checked before the timeout ticks), so a larger bound only lengthens
the wait before force-killing a genuinely wedged task.
Hardware-verified on V3: a 2-slot stop that force-timed-out at 8s pre-fix
now logs "timeout 21000 ms" and acks clean in ~11.7s. Native suite +
both observer firmware builds green.
Fork-owned, host-tested MQTT bridge lifecycle state machine and the narrow
dependency seam to drive it deterministically, plus the cross-core ownership
model. This is the Phase 4 "ownership and teardown test seams" safety net that
must land before the Phase 5 cooperative-shutdown refactor.
- src/helpers/MQTTLifecycle.h: pure state machine
(Stopped->Starting->Running->StopRequested->Stopping->Stopped) + injected
Ops seam (clock / task / resource owner / OTA barrier) + Coordinator with a
bounded stop timeout. No Arduino/FreeRTOS/WiFi deps.
- test/test_mqtt_lifecycle/: 18 GoogleTest cases covering the phase's teardown
matrix (stop during every activity, callback timing, duplicate/early stop,
restart, timeout fallback, no-access-after-release) and the OTA-barrier
scenarios.
- MQTT_OWNERSHIP.md: one owner per mutable runtime domain, current cross-core
hazards with file:line references, target primitives, and Phase-0-pending
(hardware-characterization) items.
- STABILITY_TESTABILITY_HANDOFF.md: Phase 4 status and verified premise
refinements.
Scope: MQTTBridge.cpp is intentionally untouched. The production rewiring
(plain-data snapshot publication, volatile-handshake replacement, cooperative
shutdown) is deferred to Phase 5.
mikecarper
agessaman