RegisterNotificationAsync published a refused registration into
NativeRegistrations under ConnectGate with NextRetryUtc = MinValue; the
SubscribeAsync caller booked the refusal backoff (NoteDeadFailure refused:
true) only after the gate was released and after its WARN. A probe tick in
that window took the gate, saw the registration as due, and retried it at
once - the CI flake in A_rearm_during_an_in_flight_retry_is_not_lost
("AttemptsFor(\"MAIN.T\") should be 1 but was 2").
RegisterNotificationAsync now books the failure (refusal backoff, or the
comms-class every-tick retry) before it publishes the dead registration, still
under the gate. The caller no longer books the refusal a second time (that
would double the backoff); its comms-class booking is idempotent and stays.
Tests: TwinCATCapturingLogger gains an OnWarning hook. A logger that holds
the refusal WARN for ten probe intervals forces the window open, so
A_rearm_during_an_in_flight_retry_is_not_lost exercises it on every run, and
the new A_refused_registration_is_published_with_its_backoff_already_set
pins the backoff (booked once, not doubled).
Pass rate of A_rearm_during_an_in_flight_retry_is_not_lost:
- before, unmodified test: 40/40 runs, plus 200/200 in-process repeats under
CPU load (the natural window is a few instructions wide; the flake is rare);
- before, window held open: 0/32 (deterministic failure, "should be 1 but
was 2");
- after, window held open: 40/40.
Full TwinCAT suite 663/663 at AKKA_TEST_TIMEFACTOR 1 and 3.
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV
- I1: the poll engine belongs to a teardown generation. ShutdownAsync/Dispose
retire the current engine and install a fresh one in the same swap as the
device/tag tables, then dispose the retired one (possibly in the background
after a cancelled or over-budget shutdown). A subscription made after the
next InitializeAsync can no longer land in an engine whose late dispose tail
would dispose its CTS without cancelling it (a loop no UnsubscribeAsync could
find). Poll handles are generation-qualified (TwinCATPollHandle) because each
engine numbers handles from 1; SubscribeAsync re-homes a subscription that
raced a retirement.
- M1: a write's status feeds per-device health - Good clears that device's
comms fault and advances LastSuccessfulRead, a comms status degrades, a
refusal keeps the state.
- M2: a symbol-version re-arm bumps a per-registration epoch; an in-flight
retry that fails afterwards no longer re-imposes the backoff.
- M3: a re-arm restarts the refusal backoff at 30 s.
- M4: documented that PLC-not-in-RUN detection needs the probe.
- M5: WSTRING and multi-dimensional array encode-plan tests; the cancelled-
shutdown test asserts Unknown health and awaits its background teardown.
- M6: an infinity spelled as a string ('Infinity', '-inf') passes like a
float/double infinity; a finite overflow stays BadOutOfRange.
Refs #739
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty