I1: the U11 Bits[n] -> Bits[n/32] rewrite was unconditional. The native
runtime now keeps the original element path until the first reply settles the
layout: 0xD3 confirms DWORD addressing (bit n%32); any other reply type (e.g.
a 0xC1 per-element BOOL array) or a refusal of the DWORD index falls back to
Bits[n] and re-reads, and a write settles the layout by a read first, so it can
never decode or write element n/32 of an element-addressed array.
I2: libplctag ErrorNoMatch/ErrorBadDevice no longer fold into NotFound (they
now read as BadConnection: comms, Degraded, LastSuccessfulRead preserved).
ErrorNotImplemented - and the native runtime's own pre-send refusals - raise
AbCipLocalRefusalException: BadNotSupported, no health, LastSuccessfulRead NOT
advanced, no backoff record, not reachable for the probe or Test Connect.
M1: the bit RMW's parent read/write status words follow the health contract
(refusal: per-tag Bad + Warning; comms: evict the parent + Degraded).
M2: device Unsupported read refusals return Refused (advance
LastSuccessfulRead); device write refusals call RecordWriteAnswered (not the
pre-send native type gate).
M3: a good write clears a Degraded a write comms fault recorded (a read-side
Degraded is still left for the read path).
M4: a superseded init throws AbCipInitializationSupersededException (not an
OCE); ShutdownAsync stamps Unknown only if no newer init published meanwhile.
M5: the sync-Dispose timing assert is 2 s against a 4 s probe read; the
unencodable-array test asserts health.
Refs #737
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Native is the default, so a locally refused write must not look like a comms fault.
- AbLegacy: an AbTransportException with AbStatus.Unsupported (status-bit sub-element writes, PLC-5
non-N reads, all PLC-5 writes; libplctag's ErrorUnsupported maps here too) now returns
BadNotSupported on both the read and the write path (incl. the bit-RMW path). The tag handle is
not evicted and driver health is not touched. A native runtime whose init read is refused locally
is CACHED rather than disposed, so a poll of a refused tag does not re-create (and re-lease the
pooled connection) every cycle.
- AbCip: the same mapping on the write path and both read paths (single + whole-UDT).
- Uses the existing named BadNotSupported constants (StatusCodeParityTests guard).
- Tests (falsified by disabling the mapping, and separately the keep-on-refusal): status-bit
writes and PLC-5 read/write through the driver over the native runtime — BadNotSupported, zero
wire requests, one create, health unchanged; AbCip refused read/write via a refusing fake plus a
control that a non-refusal failure still evicts and degrades.
- Docs/CLAUDE.md: BadNotSupported; #571 known-gap wording removed.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Joseph Doherty