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
- I1: the upgrade restart itself moves every no-key AbCip/AbLegacy driver to Native (every process
start constructs drivers, incl. boot-from-cache). Docs + CLAUDE.md now say so and tell operators
to set "transport": "Libplctag" BEFORE upgrading (older builds ignore the unknown key).
- I2: AbLegacy release note leads with the status-bit write refusal (T4:0.DN, C5:0.CU, R6:0.EN, ...)
on defaulted SLC/MicroLogix drivers and the fallback. The real client status is
BadCommunicationError, not BadNotSupported (the driver's write catch-all maps the runtime's
AbTransportException like any transport failure, as #571 does for PLC-5), with handle eviction
and Degraded health; pinned by a driver-level test (no 0xAA write on the wire, with a positive
control). ST string byte order stated as unverified. Also corrects the docs' "T4:0/DN" examples:
the driver's address grammar is "T4:0.DN" ("/DN" is a malformed address).
- I3: DriverProbeHandshakeE2eTests' two AbCip probe tests are a [Theory] over Native and
Libplctag. Run against ab_server controllogix: all 4 rows pass with identical exact messages.
- M1: documented (docs + resolver XML doc): the AdminUI merges only the probed device, so a
mixed-family defaulted AbLegacy driver can probe Native while running Libplctag.
- M2: factory ParseEnum rejects undefined integer strings ("7") via Enum.IsDefined (both drivers).
- M3: AbCip driver-level bad value reads "AB CIP config in '<id>' has unknown Transport ..."; the
named constant is gone (tagName: null now means driver-level).
- M4: the explicit-Native limited-family Warning is once per instance, not per (re)init.
- Nit: EffectiveTransport docs note that injected factories bypass it.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Task 22 (spec section 8 P5), with the controller rulings that exclude PLC-5 and LogixPccc.
- Transport is nullable on both option records; null (key absent) means "use the default" and is
never serialized. Factory DTO parse: absent -> null; a bad value still fails via ParseEnum.
- One resolver per driver (AbCipTransportResolver / AbLegacyTransportResolver), used by the driver
constructor, the Test Connect probe and (through the driver) the CLI.
AbCip: null -> Native. AbLegacy: null -> Native unless any device is Plc5 or LogixPccc, then the
whole driver resolves to Libplctag. Explicit values always win; explicit Native with a
Plc5/LogixPccc device logs one Warning at init.
- Init log shows configured vs effective, e.g. transport=Native (default).
- AdminUI forms: "Default (...)" / "Native (managed)" / "libplctag (fallback)". Default omits the
key on save (reverses Task 19's explicit re-emit, which would have pinned every edited driver).
- CLIs: --transport default|native|libplctag, default "default" via the resolver, so
--plc-type Plc5 with no --transport runs libplctag.
- Tests pinned to Libplctag where a default-path runtime was created: found by instrumenting the
native factories with the current xUnit test name (one unit test, AbLegacyReinitConfigAdoption;
plus the two fixture-gated AbCip probe E2E tests whose exact messages were proven on libplctag).
TransportMatrix and the differential harness already pass explicit transports.
- Switch/resolver/CLI/form tests are falsified by mutating the resolver (default -> Libplctag,
exclusion removed, AbLegacy default -> Libplctag): each mutation turns them red.
- Replaces the inline role-name literal in AbCipDriverFactoryExtensions' ParseEnum call with a named
constant; RoleAuthorityGuardTests was already red on the base commit for that line.
- Docs: AbCip.md / AbLegacy.md default + release note; CLAUDE.md AB section.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Pass 2 (2026-10-08 00:21Z, df776170): 17/17. Browse 3162=3162 tags, 20 UDT
templates identical, 200 tags read with 0 unexpected divergences (6 live
values compared structurally + every still element), 1 Forward Open and 1
acked Forward Close per native phase. Latency native p95 105.8 ms vs
libplctag 139.5 ms (limit 153.4) PASS. Pass 1 failures and their fixes are
recorded in the gate-results doc; pass 2 had no independent pcap.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
The 5069-L3x supports the Large open, as the press proved. The narrow/refusing case is a pre-v20 1769-L3x or a bridge. AbCipDeviceOptions.ConnectionSize: the native transport honours it on the wire; libplctag ignores it.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
M2: after plc_tag_destroy, the release writes 0 back to the wrapper's nativeTagHandle, so a repeat release is a no-op instead of touching a destroyed id. The runtimes keep the destroyed handle for tests and diagnostics.
M1: the rooting fallback is now described accurately, as an unbounded leak (one native tag per failed create), not a bounded one. A test seam (ForceRootingForTest) pins that the fallback roots the tag and destroys nothing.
Both pins are red with their line removed. The orphan tests share a non-parallel collection, because the counters and the seam are process-wide.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
I1: a live verdict no longer waives the value check. Only elements that moved between the two libplctag reads are excused.
- An element equal in both libplctag reads must also be equal through native; otherwise **NO: stable element i**.
- A moved element must not read NaN or infinity on native unless libplctag saw it too; otherwise **NO: non-finite element i**.
- Live tags log their full raw bytes and every element, and the summary reports live tags as N of the total.
- The offline pin adds the pass-1 Real[5] shape: a stable element shifted on native fails. It is red with the element check disabled.
M9: after each native phase (differential and latency), wait for the session close. With AB_DIFF_COUNT_OPENS=1, assert exactly one Forward Close was sent, using the new CipConnection counters; acked is logged.
M8: each latency pass logs its GC collection deltas (gen0/1/2) for both transports, plus native per-exchange round-trip min/mean/max.
M4: the latency test also asserts that no libplctag orphan had to be rooted.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
CipConnection gains two process-wide gate-diagnostic counters next to ForwardOpenCount: ForwardClosesSent (incremented as the request goes on the wire) and ForwardClosesAcked (incremented when the reply arrives within the 1 s budget).
It also records round-trip statistics for completed exchanges: ResetExchangeStats() clears them and ReadExchangeStats() returns count, min, max and mean. The cost is two Stopwatch reads and a few interlocked operations per request. No behaviour changes.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
In T21 press pass 1, two REAL tags diverged only because their live values moved
between the sequential libplctag and native phases (WW_M4ActualTemp 384.887 ->
385.138).
The libplctag phase now reads every selected tag a second time, paced, before
native starts (TransportObservations.ProbeReads). A tag whose two libplctag reads
both succeed and differ is classed live. For a live tag, parity still requires:
- the same status (and the native-TypeMismatch rule);
- no decode error;
- the same raw length;
- the same CIP type code when both sides expose one (native records it now;
libplctag.NET 1.5.2 does not);
- the same decoded shape.
Value equality is not required. Live tags get their own list and a "libplctag
probe" table column, and are counted as neither expected nor unexpected
divergences.
A tag that reads stable on libplctag but differs on native is still an unexpected
divergence, and a missing or failed probe never makes a tag live. The offline pin
A_live_value_is_compared_structurally_and_a_stable_one_by_value goes red with the
live branch disabled.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
The T21 press pass 1 test host died at exit with "A callback was made on a garbage
collected delegate of type ...plctag+callback_func_ex::Invoke". The cause is in
libplctag.NET 1.5.2. When a tag's create fails, for example with NotFound,
InitializeAsync throws with the callback still registered. Dispose() destroys a tag
only if it is initialised, so the native tag outlives its wrapper. The GC then frees
the delegate, and libplctag's atexit plc_tag_shutdown raises DESTROYED into it.
Reproduced against ab_server: the production LibplctagTagRuntime with a NotFound tag
exits 134 with that exact message, and exits 0 with this fix.
A timed-out create unregisters its callback but never destroys the handle either,
so that native tag keeps reconnecting for the life of the process.
The fix adds LibplctagOrphanRelease (AbCip and AbLegacy). After a failed
initialise/read/write that leaves the tag uninitialised, it reads the handle through
the pinned wrapper's private fields, unregisters the callback and destroys the tag.
If those fields cannot be read, it roots the tag for the life of the process
instead. It is applied in both tag runtimes, the symbol-listing reader and the
template reader. GetStatus keeps the status the tag held before it was destroyed.
Pins: offline refused-connection tests in AbCip.Tests and AbLegacy.Tests, a live
NotFound test on ab_server, and a reflection-shape pin. All go red with the release
disabled. The differential harness also asserts that no orphan had to be rooted.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
- AbCip/AbLegacy driver forms gain a Transport InputSelect; FromOptions/ToOptions now carry
Transport, so saving any other field no longer silently reverts Native to libplctag.
- Both drivers log the constructed transport once per init.
- AbCip factory now takes the host ILoggerFactory (it ran on NullLogger in production, hiding
every AbCip log line); DriverFactoryBootstrap passes it.
- Gate results: AdminUI /run (T19) native, inverted (dead port) and libplctag legs.
The libplctag adapters assigned Tag.Path straight from the device's parsed
CipPath. A device address with no route (ab://host:44818/ - the normal
Micro800 form, and a MicroLogix with no route) parses to "", and libplctag
rejects an empty path attribute with ErrorBadData; omitting the attribute
(null) is what it accepts. So Micro800 could not connect on the default
libplctag transport.
This predates the native transport work and exists on master.
Add an internal LibplctagPath.Normalize helper per driver project (blank ->
null) and route all four Tag constructions through it (AbCip tag runtime,
symbol-list enumerator, template reader; AbLegacy tag runtime). The runtime
tag construction is extracted to an internal BuildTag so tests can inspect
Tag.Path without connecting. Tests fail with Normalize reverted to identity.
Update the Micro800 smoke-test comment: both transports are expected to pass.
ab_server answers every Execute PCCC with a fixed requestor id (pccc.c
PCCC_RESP_PREFIX: 07 3D F3 45 43 50 21) instead of echoing the request's, so
the R14-3 echo check rejected every native reply sent under the 0x1337 CIP
originator identity as BadReply. The pooled runtime now sends libplctag's
identity (PcccServices.RequestorVendor/RequestorSerial), which passes the echo
check against ab_server and against a real controller that echoes. Pinned by a
FakeEipServer round trip that answers with ab_server's fixed prefix.
ab_server's RegisterSession sanity check rejects any non-zero sender context
with encapsulation status 1 and a header-only reply, so every native session
against the simulator failed with BadCommunicationError. libplctag sends zero
(logix-register-session.hex); the codec test now matches that capture byte for
byte instead of excluding the context, and a client test pins the zero on the wire.
Scheduler tests (exclusive mid-queue and at head) and a template-reader test that
genuinely queues a Read Template behind a small read; bounded QueuedCount wait
replaces the fixed delay. Falsified: removing exclusive from the reader turns the
reader test red; removing the Exclusive handling in RequestScheduler turns all three red.
Joseph Doherty