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
Review r0 I1. On the default libplctag transport a PLC refusal (non-zero PCCC
STS, e.g. an element past the end of the file; or a CIP error) arrives as
ERR_REMOTE_ERR / ERR_BAD_STATUS, which fell into the BadConnection default: a
no-reply comms fault. A coalesced block with one such member then failed as a
group every poll, and two refused tags in a row opened the device's fail-fast
window against a device that was answering.
- LibplctagLegacyStatusTranslation maps ERR_REMOTE_ERR / ERR_BAD_STATUS to the
existing AbStatus.DeviceStateConflict (BadDeviceFailure): "reachable, refused
the operation". No new AbStatus value (Driver.Ab.Transport is Lane K's).
- IsNoReply (Timeout / BadConnection / Abort / Pending / unknown codes) is now
the ONLY comms-fault class; IsDeviceRefusal is every other non-Ok status
except Unsupported (BadReply / Partial included: a reply arrived).
- A coalesced block refused with ANY returned status falls back to per-member
reads in the same pass; the shape is remembered only after a repeat, and the
refused block's handle is always evicted (M5).
- A runtime status Unsupported is neutral (keeps the handle); the probe no
longer counts it as a fault.
- Refusal warnings log the status actually answered (M8).
Live: the new past-end-of-file ab_server case fails on libplctag with the old
translation and passes with it, on slc500/micrologix/plc5 x both transports.
Refs #738
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Review 07 P7 (rest): adjacent words on one data file were never coalesced
(one round trip per tag) although the array path proves the transport can read
a span. Within a device pass, scalar tags on one N/B/F/L file within 8
elements of each other (block <= 200 data bytes, under the 236-byte typed-read
limit) now ride one multi-element read and are decoded from their offsets with
exactly the CLR types the single-tag path returns (int / float / bool).
Only shapes the single path decodes identically are coalesced: indirect,
sub-element, array, file-number-less (S:/I:/O:) and width-mismatched tags keep
the single path. A block the device refuses (an authored element past the end
of the file, a native PLC-5 non-N file) falls back to per-tag reads for its
members and its shape is remembered; a comms fault fails the members together.
New driver-config key coalesceReads (default true) with an AdminUI switch
(Razor change: AbLegacyDriverForm, for the Wave 4 live check). Adds an
env-gated ab_server parity case (coalesced == per-tag values).
Refs #738
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty