MAJOR-1: the SDK skips TypeInfo.IsInstanceOfDataType on any node with an
OnWriteValue handler (every writable equipment node), and the node manager's
fail-fast treated numeric<->numeric as compatible, so a UInt32[] to a Galaxy
Int32 array matched MxValueEncoder's int[] arm by CLR covariance and was
written bit-reinterpreted with a Good result. EvaluateEquipmentWriteStructure
now matches an ARRAY write's element type exactly (Byte[]/ByteString the only
equivalence; Variant[]/object[] refused) -> BadTypeMismatch, nothing
dispatched. MxValueEncoder's int[]/long[] arms are exact-type guarded too, and
the Galaxy parity test's false "the SDK refuses" premise is corrected (the
UInt32/UInt64 exclusion is now the encoder's own answer). Scalar writes keep
numeric widening by decision: consumers write CLR-typed values (Double to a
Float node) and every driver's scalar encoder range-checks.
MINOR: Modbus row honours maxRegistersPerWrite (smallest of DriverConfig /
the tag's DeviceConfig, default 123) and FC15's 1968-coil ceiling, and
requires region + numeric address; Modbus/S7/Galaxy require isArray + integer
arrayLength >= 1 (Galaxy: an unbounded node would let a short write resize the
attribute); an array value to a scalar node is refused inline. Docs: Uns.md
array-write rules + upgrade note (ReadWrite array tags become client-writable
on first boot), Modbus.md, Galaxy.md.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Array nodes were forced read-only for every driver. A new single authority,
Core.Abstractions DriverArrayWriteSupport, says which (driver, element type)
pairs encode a whole-array write: Modbus (Coils / numeric HoldingRegisters),
S7 (Byte/Int16/UInt16/Int32/UInt32/Float32), OpcUaClient (pass-through) and
Galaxy (Boolean/Int32/Int64/Float/Double/String/DateTime). Everything else
stays read-only, so the server never advertises a write the driver refuses.
- Composer derives RawTagPlan.ArrayWritable + UnsReferenceVariable
.BackingArrayWritable at compose time (both seams, byte-parity); the
applier's one writability rule is Writable && (!IsArray || ArrayWritable)
for materialise and surgical paths, raw and UNS alike.
- ArrayWritable is on the classifier's surgical raw-tag whitelist and
mirrored on the UNS record (UnsReferenceBackingParityTests updated).
- Node manager refuses a wrong-length / non-array value on an array node
(BadTypeMismatch) and any IndexRange write (BadWriteNotSupported) inline,
before dispatch; WriteOperate/ACL gates and the revert are unchanged.
- Per-driver parity tests pin the table against the real Modbus write path,
S7 EncodeArrayBlock and Galaxy MxValueEncoder (UInt32/UInt64 excluded:
array covariance reinterprets their bits).
- Over-the-wire proof in OpcUaServer.IntegrationTests (ArrayWriteWireTests).
- ValueRank > 1 documented as out of scope by decision (docs/Uns.md).
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
- Galaxy: deadline bounds the wait, not the subscribe RPC; BadTimeout for all tags and late handles unsubscribed; doc comment relocated
- S7: probe connect runs on the connect deadline so a timeout opens the backoff window
- S7: a successful write only retires a Faulted the write side owns
- S7: null array elements rejected (BadTypeMismatch); multi-PDU array writes documented non-atomic
- S7 integration: array write test gated on S7_SIM_ALLOW_WRITES=1
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
A first-touch native write to a T/C/R status-bit sub-element (T4:0.DN) created
and initialised the tag's runtime before the runtime's write refusal could fire;
the init is one READ, so against a device lacking the file (the ab_server
fixture has no T/C/R) it surfaced as BadCommunicationError + Degraded health
instead of BadNotSupported. The bit-RMW path was not involved: AbLegacyAddress
rejects sub-element + /N, so a status bit's BitIndex is always null.
NativeAbLegacyTagRuntime.WriteRefusal is now the single predicate (status bit
by address whatever the authored type; any PLC-5 write), asked by the driver via
IAbLegacyTagFactory.WriteRefusal (default null, so libplctag is unchanged)
before EnsureTagRuntimeAsync and ahead of the bit-RMW branch.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
STAB-21 ConnectionBackoff in EnsureConnectedAsync; STAB-22 write-pass accumulator with a
write-side Faulted that a clean read does not erase; _health on the Volatile idiom;
S7-016 contiguous array write (Bool arrays stay refused).
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
LastFixedPollUtc is stamped by the fixed-tree bootstrap before any axis snapshot
is published, so under load Each_duplicate_axis_reads_its_own_position could read
inside that window and get BadNodeIdUnknown. The helper now waits for the last
axis slot plus the servo/spindle caches. 45/45 green under 14-core yes load.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
The driver stamps DateTime.UtcNow at init and again per read pass; under CPU
contention both land in the same tick, so the strict greater-than assertions
flaked (reproduced 1/40 under load, sibling test A_cancelled_pass_still_flushes...
failed identically with equal timestamps). Test-only race; no production defect.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
The libplctag-path positive control asserted 'timed out', but libplctag's internal
timeout equals the probe timeout and races the probe's own cancellation; under CPU
load it surfaces as 'ErrorTimeout' instead. Accept either libplctag stall outcome
(native never produces either: it fails at once with 'Connection lost').
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Ab.Transport.Tests: predecessor-wait counter instead of 300 ms (DeviceSessionPoolTests x2), throttle
queue/interval-park hooks instead of 50/100 ms (ForwardOpenThrottleTests x2), UnobservedTaskProbe with a
must-report control fault instead of N GC cycles (EncapsulationClientTests), re-armed keep-alive timer as
the control for the never-opened keep-alive test.
AbCip.Tests: still-polling sibling / control driver read counts instead of 300-500 ms (subscriptions x4,
alarm projection x5), structural ProbeTask==null + enabled-probe control (host probe x2), predecessor
wait (NativeAbCipLeaseReleaseTests), processed waits in the shutdown/logging tests.
AbLegacy.Tests: sibling-subscription control (Unsubscribe_halts_polling), ProbeCts==null + control.
AbCip.IntegrationTests differential safety: a post-phase control open through the same throttle instead
of 1.5-2.5 s sleeps (via a native tag init, keeping the harness read-only guard green).
Fake tag ReadCount made interlocked; CapturingLogger entries snapshotted under a lock.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
- Process-wide CipConnection statics (ForwardOpenCount, Forward Close counts, RequestsSent, exchange
stats, OpenAttempts, OpenAttemptBudget) move to an instance ConnectionDiagnostics owned by each
DeviceSessionPool (and by a stand-alone CipConnection). The open-attempt budget becomes a disposable
per-DeviceKey limit (LimitOpenAttempts); the differential harness scopes one to the press under test.
- LibplctagOrphanRelease.ForceRootingForTest is gone: ReleaseIfOrphaned(tag, canReadHandles) overload.
- A connected reply with general 0x01 / extended 0x0107 or 0x0203 (target no longer holds the class-3
connection, TCP still up) retires the session at once; the next send reopens through the throttle.
- New tests: dispose during RegisterSession, abandoned-open observer (falsified), scheduler-dispose-throws
guard (DeviceSessionPool.CloseAsync), release-in-background with a shared open in flight, per-device
limit scoping, CIP-close recycle (request + keep-alive + negative control).
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
#570
- STRING: the built-in 88-byte Logix STRING holds 82 characters (LEN + DATA[82] + 2 pad), not 84; the
write still sends the whole 88-byte structure and a read never decodes the pad as characters.
- Mistype churn: a type refusal (CIP 0xFF/0x2107) on the existence read no longer throws from
InitializeAsync, so the runtime is not disposed/re-created (and re-Forward-Opened) every poll; the driver
also keeps a runtime that throws TypeMismatch from init and records the device as reachable.
- Malformed tag name: a TagPath that does not parse, or a name the CIP symbolic encoder refuses (now also
non-ASCII, empty member, >255-char member, unterminated subscript), is AbCipTagConfigurationException ->
per-tag BadConfigurationError (named const in AbCipStatusMapper), warned once, never feeding the device
backoff or health; siblings keep reading. A malformed probe tag no longer feeds the backoff either.
- Micro800 BYTE/WORD/LWORD (0xD1/0xD2/0xD4) are type-checked as integers of their width: REAL/LREAL or a
narrower integer over LWORD is TypeMismatch, not decoded garbage.
#579
- ConnectionLease.ReleaseInBackground: one non-blocking release shape for both native AB runtimes. The
AbCip runtime's Dispose no longer waits up to 2 s under the per-tag lock; the pool still registers the
close synchronously so a re-create cannot overlap it. Offline soak tests (25 cycles, AbCip + AbLegacy)
prove no leaked connection; FakeEipServer gains OpenConnections.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
#572: listing continues at max(instance in page)+1 (no ascending-order assumption, no-progress guard kept);
browsePageDelayMs (default 5 ms) paces pages; DiscoverAsync reads templates through one batch reader
(IAbCipTemplateReaderFactory.CreateBatch) holding one lease.
#575: differential harness reports a same-status template refusal as an equal refusal; offline test pins the
open-attempt budget without relying on the abort ending the phase.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Joseph Doherty