QA Warm gate (lmxopcua#907, 2026-11-13): a graceful stop of the Warm Primary
reported ServiceLevel 0 for ~6 s - shorter than the 10 s degraded window - the
next unreadable sample cleared the streak, and the connection retried the stopped
node FailoverRetryCount times: Good on the peer after 66 s, peer Active in 0.2 s.
Two going-away triggers on top of #138, both still requiring a Healthy (>= 200),
higher level on the other endpoint and honouring the minimum dwell:
- ServiceLevel 0 (Part 4 Maintenance) probes the other endpoint at once instead
of waiting out the window - once per degraded streak, so a non-Healthy peer is
re-probed once per window, not every poll. Other Degraded levels (standby 90/50,
booting 1) still wait the window.
- A lost link whose session's last KNOWN ServiceLevel was < 200 (unreadable
samples don't overwrite it) probes the other endpoint before the first
reconnect attempt, holding the reconnect timer. Healthy -> switch and reconnect
at zero delay, the stopped node is never retried; otherwise the ordinary retry
cycle runs (less the probe's time). After only Healthy levels (250/240, Unset),
inside the dwell, or with the feature off: unchanged retry-then-failover.
Tests: DataConnectionGoingAwayFailoverTests (10 cases, each trigger and
non-trigger with positive controls, connect-order artifact assertions) and a real
in-process OPC UA server pair graceful-stop e2e on production defaults: 1.1 s
(lost-link trigger alone 12.1 s, neither 33.1 s -> fails the 10 s bound).
13 mutants, all killed. DCL tests 608/608 (3 full runs); solution 0 warnings.
Docs: Component-DataConnectionLayer, components/DataConnectionLayer.
Not deployed; QA live re-check pending.
Claude-Session: https://claude.ai/code/session_01GT67ACmpMR7b9LGRPLijMi
Joseph Doherty
c4ec51e89a