Review r1 N1 (Important): the I1 fix made IsDeviceRefusal default-open and
mapped libplctag's ERR_REMOTE_ERR to an answer. libplctag folds EVERY non-zero
PCCC STS and CIP status into that code, including a routing hop's "unconnected
send timed out" / "connection lost" / "remote node missing", and native
BadReply covers truncated / mismatched / unmapped replies - so a powered-off
PLC behind a bridge read as reachable: Healthy, LastSuccessfulRead advancing,
the comms-loss watchdog unable to fire.
Three classes now, each pinned both ways:
- no reply (Timeout/BadConnection/Abort/Pending/unknown): comms fault;
- answered - an ALLOW-LIST again (NotFound/NotAllowed/OutOfBounds/TooLarge/
TooSmall/TypeMismatch/DeviceStateConflict): proves reachability;
- OPAQUE (BadReply/Partial; ERR_REMOTE_ERR/ERR_BAD_STATUS now translate to the
existing BadReply, OPC UA BadCommunicationError as before r0): per-tag Bad,
handle kept, coalescing fallback, never fail-fast, never an answer. Option
(a): a device whose pass/call produced only opaque outcomes is Degraded with
LastSuccessfulRead not advanced, so the watchdog reaches a dead routed PLC.
The probe and index reads classify the same way.
Minors:
- N2: a mismatched array (type vs data file) READS BadTypeMismatch instead of
decoding the file at the wrong width as Good.
- N3: a swept indirect resolution is never reconnected under a forgotten gate;
that one call answers neutrally.
- N4: an index read answered Unsupported is neutral, not a transport fault.
- N5: ArrayFileMismatch checks indirect addresses (the file letter is static).
- Test nit: the evicted-while-waiting test signals gate arrival via a seam
instead of sleeping.
Live: 51/51 on ab_server (slc500/micrologix/plc5 x both transports), incl. an
opaque-only libplctag device staying Degraded with LastSuccessfulRead frozen.
Refs #738
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty
e3cb4f0c7b