Vendors the NORMATIVE (proto2) Eclipse Tahu sparkplug_b.proto and compiles it
in .Contracts with build-time Grpc.Tools, message-only (GrpcServices="None") --
Sparkplug rides MQTT, there is no gRPC service, so no Grpc.Core.Api is pulled in.
Provenance rides in the file header: repo, path, pinned commit
5736e404889d4b95910613040a99ba79589ffb13, permalink, git blob SHA-1
bf72ab5f..., content SHA-256 4432c5c4..., EPL-2.0, and a re-verify recipe. The
body below line 38 is byte-for-byte upstream; the blob SHA-1 matches the tree
entry at that commit, so the copy is provably genuine and not reconstructed.
Chose the proto2 file over upstream's sibling sparkplug_b_c_sharp.proto: the
sibling is a lossy proto3 restatement that drops explicit presence, and protoc
generates valid C# from proto2 into the identical namespace
(Org.Eclipse.Tahu.Protobuf, PascalCased from the package -- no
csharp_namespace option). Presence matters downstream: an NBIRTH legitimately
carries seq = 0 and a DATA metric legitimately omits `name`, so Has{Seq,Name,
Alias,IsNull,Datatype} is the difference between "absent" and "present, zero".
.Contracts stays transport-free: Google.Protobuf is a serialization dependency
with a framework-only graph, Grpc.Tools is PrivateAssets=all, and the resolved
graph is exactly {Google.Protobuf, Grpc.Tools, Core.Abstractions} -- no MQTTnet.
Codegen tests pin the round-trip, the namespace, the Sparkplug field numbers,
the DataType spec indices, and protoc's enum-name mangling (UInt64 -> Uint64,
UUID -> Uuid) that Task 17's datatype map has to spell correctly.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
The P1 live gate had to insert MQTT driver config directly via SQL: DriverConfigModal and
DeviceModal both fell through to "No typed config form for driver type Mqtt" with no raw-JSON
fallback, so broker host/port/TLS/credentials were unauthorable from the AdminUI. Task 12 built
the *tag* editor; these are the driver + device surfaces.
MqttDriverForm authors the whole MqttDriverOptions connection surface (host/port/clientId,
TLS + CA pin, credentials, protocol version/clean-session/keep-alive, connect timeout, reconnect
backoffs, mode, maxPayloadBytes, and the Plain sub-object). The Sparkplug sub-object stays P2 —
a marked placeholder mirroring MqttTagConfigEditor's stub, with any existing sparkplug keys
preserved untouched.
The connection is authored on the DRIVER, not the device — unlike Modbus/S7/OpcUaClient and
contrary to what docs/drivers/Mqtt.md said. DriverDeviceConfigMerger merges a device's keys up
only when the driver has exactly ONE device, so a device-authored broker connection vanishes
silently the moment a second device is added. MqttDeviceForm is therefore informational (the
GalaxyDeviceForm shape) and round-trips DeviceConfig verbatim; it flags legacy connection keys
left on a device by a pre-form deployment, because those still win via merge-up.
Serialization goes through the ONE shared MqttJson.Options instance (Task 9's decision), never a
fifth per-form copy — pinned by an assertion that an ordinal-only reader CANNOT bind the emitted
blob, and by extending the fleet-wide DriverPageJsonConverterTests guard to resolve a form's
serializer from an explicit external-instance registry when it has no _jsonOpts field. Dropping
the converter from MqttJson.Options reddens 3 tests and leaves the symmetric round-trip green —
the Task 9 lesson, reproduced.
RawTags is stripped from the emitted blob (the deploy artifact owns it) and unknown top-level
keys survive a load->save. Validation mirrors the driver's own [Range] bounds inline, and
ToOptions() additionally clamps, so an ignored error still cannot persist a
connectTimeoutSeconds:0 driver-brick. A non-blank clientId raises the P1 live-gate warning
inline (fixed ids make redundant pair nodes evict each other while both report Healthy).
AdminUI 761/761 green (was 730), TWAE-clean; Driver.Mqtt 266/266 green.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
The read-only Sql driver's runtime factory/probe and tag-side editors were
wired, but the AdminUI could not author the DRIVER: the /raw "New driver" type
list, the DriverConfigModal switch, and the legacy identity dropdown all omitted
Sql, and no SqlDriverForm existed. Live-driving the AdminUI surfaced this.
- Add SqlDriverForm.razor over the SqlDriverConfigDto shape: Provider
(SqlServer-only in v1), required connectionStringRef (an env-var NAME, not a
connection string — label is explicit), optional poll/operation/command
timeouts, maxConcurrentGroups, nullIsBad. Enums serialize by NAME via
JsonStringEnumConverter; a connection-string literal can never be authored
(no such field is collected); rawTags (composer-owned) + allowWrites (inert,
read-only v1) are never emitted.
- Wire Sql into DriverConfigModal switch, RawDriverTypeDialog type list, and
DriverIdentitySection legacy dropdown.
- Add SqlDriverFormContractTests: the exact JSON the form emits constructs a
driver through the real factory, missing connectionStringRef is rejected, and
provider round-trips as the "SqlServer" name (never an ordinal).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Task 14 — the P1 milestone gate. Ran the live /run verification on a docker-dev
rig against the real Mosquitto TLS+auth fixture, and recorded the result.
The gate did its job: it found MQTT was unauthorable in production.
RawDriverTypeDialog's driver-type list is a hand-maintained array that nobody
added MQTT to, so the /raw "New driver" picker never offered it — with every
other layer (contracts, driver, browser, factory, host registration, typed tag
editor) complete and 266 green unit tests. Nothing tied that array to
DriverTypeNames and AdminUI has no bUnit, so no offline test could see it.
Fixed, plus RawDriverTypeDialogParityTests: a reflection parity guard that
fails for ANY DriverTypeNames entry missing from the picker. Verified
falsifiable — RED with "…cannot be authored from the /raw New-driver picker,
so they are unreachable in production: Mqtt" before the one-line fix.
A second gap is left OPEN and documented, not fixed (no task ever covered it):
MqttDriverForm / MqttDeviceForm do not exist, and DriverConfigModal/DeviceModal
have no raw-JSON fallback — so an operator can create an MQTT driver but cannot
author its broker endpoint or credentials. P1 is not operator-complete until
those two razor forms land. The gate authored config via SQL to get past it.
Live gate result (isolated 2-node MAIN stack, image built from this branch,
fixture at 10.100.0.35:8883, AllowUntrustedServerCertificate rather than
pinning the CA into the rig):
- typed MQTT tag editor renders and round-trips; Json shows the JSON-path
field, Raw/Scalar hide it; wildcard topic a/+/c blocked at save; data-type
list offers Float64 and no Double; qos/retainSeed absent on "(driver
default)" and qos:2 written as a number; isHistorized/historianTagname
survive a topic-only edit; SparkplugB renders the P2 placeholder and
switching back keeps Plain values; jsonPath is guidance not a gate in all
three shapes ($ seeded only for a brand-new blank tag, blank stays absent,
clearing saves fine)
- deployed, and both editor-written blobs resolved and served changing live
values through OPC UA (22.8 / 1629, StatusCode Good) — no BadNodeIdUnknown
- the bespoke #-observation browser drove a real broker session and rendered
the fixture's actual topic tree (line1/{counter,state,temperature},
noise/chatter, retained/seed); a Modbus device's picker still correctly
reports "Browsing unavailable"
Also found live and documented (not a code change): both nodes of a redundant
pair run the driver, so a FIXED clientId makes them evict each other forever —
the broker logs "already connected, closing old connection" and both nodes
reconnect every ~2s while still reporting Healthy. Unset (the default) is
correct; confirmed 0 reconnects/60s on both nodes after removing it.
Suites: offline 1134 passed / 0 failed (266 Driver.Mqtt + 730 AdminUI incl. the
3 new guards + 138 Core.Abstractions); live 7/7 against the fixture.
Docs: new docs/drivers/Mqtt.md + Mqtt-Test-Fixture.md (the per-driver + fixture
convention every other driver follows), MQTT rows in docs/drivers/README.md,
TestConnectProbes.md, root README.md, and infra/README.md §3.
CLAUDE.md drift corrected while adding the MQTT endpoints:
- the "every fixture carries project: lmxopcua" claim was false — only the
MQTT fixture does; the filter returns one stack, not the fleet
- lmxopcua-fix.ps1 is Windows-VM-only; on macOS drive the host over ssh/rsync
(and the docker-dev rig itself runs locally under OrbStack)
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
MQTTnet 5 does not throw on an unsuccessful CONNACK — it returns the reason in
MqttClientConnectResult.ResultCode and v5 removed v4's ThrowOnNonSuccessfulConnectResponse,
so ConnectCoreAsync's unconditional SetState(Connected) sealed a wrong-password deployment
green: DriverState.Healthy / HostState.Running on a session that never authenticated.
Caught by the Task-13 Mosquitto fixture; 240 offline tests missed it.
ConnectCoreAsync now inspects the CONNACK and raises MqttConnectRejectedException.
Credentials/identity/protocol/Last-Will refusals are unrecoverable and set Faulted, which
stops the reconnect supervisor; transient refusals (ServerUnavailable, ServerBusy,
QuotaExceeded, UseAnotherServer, ConnectionRateExceeded, and anything unrecognised) stay
Reconnecting under backoff. MqttDriverProbe now shares the rejection wording, so the
AdminUI Test-connect button and the running driver can no longer disagree.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Adds the MQTT driver integration-test project: an eclipse-mosquitto fixture running
auth AND TLS (allow_anonymous false on both listeners), a mosquitto_pub-based JSON
publisher emitting retained messages, a cert/password generator script whose output is
gitignored, and a live suite gated on MQTT_FIXTURE_ENDPOINT that skips clean offline.
The fixture is never anonymous by design: an anonymous broker would let the driver's
TLS/CA-pin and auth paths go untested, and those fail silently. The CA-pin leg carries
its own falsifiability control (a foreign CA generated in-process must be rejected).
Live gate on 10.100.0.35: 7/7 passed. It found a driver defect, reported not fixed
here (src/ is out of this task's scope): MqttConnection.ConnectAsync RETURNS NORMALLY
when Mosquitto rejects a CONNECT as not-authorized -- MQTTnet 5 does not throw on an
unsuccessful CONNACK, so a wrong broker password yields DriverState.Healthy from
InitializeAsync. The auth-negative test therefore asserts the invariant that holds
either way (no session is ever established) and documents the finding.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Review follow-up. Dropped the hard Validate rejection of a blank jsonPath under
a Json payload: the runtime defaults it to the document root, which is the real
"publisher puts a bare JSON scalar on the topic" case, so rejecting it made the
editor refuse what the driver accepts — inverting "authoring surface accepts <=>
publish accepts" — and blocked whole CSV-import batches, since this validator
also gates RawManualTagEntryModal's review grid.
Replaced with guidance: an UNAUTHORED tag (no topic AND no jsonPath) seeds the
field with "$", so a fresh tag emits an explicit "jsonPath":"$" while an
existing path-less tag keeps the key ABSENT and the driver defaults it. The
wildcard-topic rule stays strict — a wildcard has no legitimate single-Tag
interpretation.
Also: omit a blank "topic" rather than writing "topic":"", and record why the
_lastConfigJson guard diverges from the Modbus template — the landmine is a
DERIVED, NON-PERSISTED UI FIELD INFERRED FROM BLOB CONTENT (Mode), which Task
24's Sparkplug field group will be tempted to add more of. Named the host-side
dependency (RawTagModal only mutates through this callback) that keeps the
staleness trade benign today.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
C1 (Critical) — DisposeAsync went straight to TeardownAsync with no lifecycle-gate
wait, reopening the orphaned-connection class. Interleaving: ReinitializeAsync's
rebuild branch holds the gate mid-InitializeCoreAsync, past its own teardown but
before `_connection = connection`; an ungated dispose sees a null connection, does
nothing, and sets `_disposed`; the rebuild then publishes a live connection plus a
host-probe loop that every later dispose short-circuits past. Not proven reachable
today (DriverInstanceActor.PostStop calls the gated ShutdownAsync), but MqttDriver
publicly implements IAsyncDisposable, which invites `await using`.
- DisposeAsync now takes the gate with the same bounded wait + fallback teardown
ShutdownAsync uses, and sets `_disposed` BEFORE the wait.
- InitializeCoreAsync re-checks `_disposed` after the connect and disposes the
connection it just built rather than publishing it — this closes the residual
window on the bounded-timeout fallback path.
- The doc comment no longer claims parity with ShutdownAsync it did not have, and
stops conflating "don't Dispose() the semaphore object" with "don't WaitAsync".
I1 (Important) — the SameSession == false rebuild branch had no test driving it.
Adds three: an endpoint-changing delta rebuilds and Faults on a refused connect;
an ingest-only delta (MaxPayloadBytes) ALSO rebuilds, pinning that IngestIdentity
is nested inside SessionIdentity; and DisposeAsync serializes behind a lifecycle
operation parked at a new internal BeforeConnectHookForTests seam (mirroring
MqttConnection's AfterConnectHookForTests, which exists for the same race class).
Minors: comments recording that IngestIdentity names no Sparkplug field and must
grow one in P2 (tasks 21/22), and why _options/_subscriptions/_authoredRawPaths
get looser memory discipline than _health/_hostState.
Falsifiability: reverting DisposeAsync to the ungated form reddens exactly the new
serialization test ("Shouldly.ShouldAssertException : raced"); forcing SameSession
to always-true reddens exactly the two new rebuild tests. 240/240 MQTT tests pass;
forced rebuild of the driver project is 0 warnings under TreatWarningsAsErrors.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Task 9. Adds MqttDriverFactoryExtensions (DriverTypeName = DriverTypeNames.Mqtt,
direct deserialization of MqttDriverOptions — no intermediate DTO, mirroring
OpcUaClientDriverFactoryExtensions), the DriverTypeNames.Mqtt constant, and both
host wiring sites: the factory in DriverFactoryBootstrap.Register and the probe in
AddOtOpcUaDriverProbes (the admin-node path Program.cs calls in its hasAdmin
block — a probe wired only on driver nodes makes Test-connect silently dead).
Carried-forward items:
- Converges every MQTT config-parsing seam onto ONE JsonSerializerOptions —
MqttJson.Options, in .Contracts alongside MqttDriverOptions. It replaces the
probe's internal JsonOpts and the browser's separate private copy; the factory,
the probe, MqttDriver.ParseOptions and MqttDriverBrowser now all parse through
it. .Contracts is the only assembly all four consumers reference, and the
browser's reference to the runtime .Driver project is a documented layering
exception scheduled for removal — anchoring the options there would resurrect
the duplicate the day it goes away.
- Replaces the "Mqtt" literals in MqttDriverProbe, MqttDriverBrowser and
MqttDriver with the constant (string value unchanged).
- Tightens MqttDriverProbeTests.ProbeAsync_EnumAsName: it asserted only
Ok == false + non-empty message, which is also exactly what a JSON-parse
failure produces — so it stayed green under the very regression it names.
It now asserts the probe got past the parse and reached the network.
Falsifiability: deleting JsonStringEnumConverter from MqttJson.Options reddens 9
tests across 4 suites, including the tightened probe test (message becomes
"Config JSON is invalid: The JSON value could not be converted to
MqttProtocolVersion") — which the pre-fix assertions would have passed.
Also references the MQTT driver from Core.Abstractions.Tests so
DriverTypeNamesGuardTests' reflective bin scan discovers the new factory and the
constant/factory parity check stays honest.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Thin typed model over a preserved JsonObject key bag, mirroring the sibling
<Driver>TagConfigModel template. Key names and strictness rules mirror
MqttTagDefinitionFactory rather than inventing an editor-side schema; enums
round-trip as NAMES (the factory reads them strictly by name).
No FullName key: under v3 a tag is identified by its RawPath, which the factory
keys the definition's Name off — a composed identity key here would be dead
weight nothing reads.
Mode is a UI-only sub-shape selector inferred from the blob (any Sparkplug
descriptor key present) and never serialised — the driver takes Plain vs
SparkplugB from its DRIVER config. Only Plain Validate() is implemented; the
Sparkplug branch is a stub Task 24 fills, and its keys are preserved untouched.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Composes MqttConnection + MqttSubscriptionManager + LastValueCache into the
IDriver / ITagDiscovery / ISubscribable / IReadable / IHostConnectivityProbe /
IRediscoverable capability set.
- Discovery replays ONLY the authored raw tags (RediscoverPolicy = Once,
SupportsOnlineDiscovery = false) — a chatty broker can never auto-provision.
- Composition order is register -> AttachTo -> ConnectAsync; the manager's
Reconnected handler is passed through unwrapped so its throw-on-total-failure
still tears a deaf session down.
- ReinitializeAsync applies a tag-only delta in place and never faults on a bad
one; a session-changing delta rebuilds.
- ReadAsync serves the last-value cache and degrades per reference
(BadWaitingForInitialData), never throwing for the batch.
- FlushOptionalCachesAsync is a no-op: the last-value cache IS IReadable.
- Adds MqttDriverOptions.RawTags (the authored-tag delivery mechanism every
other driver's options DTO already has) and promotes MaxPayloadBytes from a
manager ctor knob to an operator-facing key.
- Converges on MqttDriverProbe.JsonOpts rather than a second, divergent
JsonSerializerOptions.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Wires the bespoke MqttDriverBrowser into AdminUI's IDriverBrowser
registrations alongside OpcUaClient/Galaxy, overriding the universal
DiscoveryDriverBrowser fallback for driverType "Mqtt".
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Test-connect probe for the Mqtt driver type: parses MqttDriverOptions
(shared enum-as-name JsonSerializerOptions), opens a bounded MQTT CONNECT
via MqttConnection.BuildClientOptions with a distinct -probe-{guid8}
client-id suffix, and classifies the outcome. Live-probed against
MQTTnet 5.2.0.1603 to confirm the real contract: a broker-rejected
CONNACK is a MqttClientConnectResult.ResultCode, never a thrown
exception, and timeout classification checks the deadline token itself
rather than switching on exception type (which varies unpredictably
between MqttConnectingFailedException and bare OperationCanceledException
for the same frozen-peer shape).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
C1 (CRITICAL). AuthoredTable routed any wildcard-authored tag into `Wildcards`
and never into the concrete topic index. But the two paths that reconstruct
state from a SUBSCRIBED FILTER STRING — OnReconnectedAsync's re-subscribe set
and DegradeTopic — both looked up that concrete-only index, and
`_subscribedTopics` keys on the wildcard PATTERN ("f/+/temp"). So:
- reconnect resolved zero filters for a wildcard tag, hit a silent early
return, and issued NO subscribe. The cache keeps its last Good value, so the
tag never turns Bad — it just stops updating forever behind a connection
reporting healthy. Exactly the silent-death mode MqttConnection's own remarks
warn about, left unguarded for wildcards.
- DegradeTopic missed too, so a SUBACK rejection of a wildcard filter degraded
nothing and left the tag at BadWaitingForInitialData.
Fix: AuthoredTable now carries `ByFilter` (EVERY def, keyed by its authored
topic filter, wildcards included) alongside `ByExactTopic` (concrete only) and
`Wildcards`. Delivery matches an incoming published topic — which never carries
a wildcard — so it keeps using ByExactTopic + the comparer scan. Every path
keyed on a filter string uses ByFilter. The distinction is documented on the
record. The silent early return is now a Warning naming the orphaned topics.
Also in this pass:
- I2: bounded decode on the dispatcher thread. A body over `MaxPayloadBytes`
(default 1 MiB, ctor-settable) is refused BEFORE any GetString/JsonDocument
parse and degrades its own tags. Unbounded decode on the shared dispatcher is
paid by every subscription, not just the offending topic. NOTE: promoting this
to an operator-facing MqttDriverOptions key (+ WithMaximumPacketSize) needs a
.Contracts edit this task is scoped out of; flagged in the XML docs.
- I3: integral-valued reals now coerce to integer tags. JS/Python edge gateways
serialize an integer as 5.0, and TryGetInt32/int.TryParse are syntactic — an
Int32 tag fed by such a gateway silently never received data. Parsed via
decimal so integrality and range are exact across Int64/UInt64. A genuinely
fractional 5.5 is still refused, never rounded.
- I4: the JSON document is parsed ONCE per message and shared across the whole
fan-out (the documented "one document, one JSONPath per signal" shape was
re-parsing per tag). Zero-alloc via a ref struct when no Json tag matches.
- I5: pinned the documented JSON-string-holding-a-number coercion end-to-end.
- Minor: Register now prunes `_subscribedTopics` / `_handleByRawPath` entries for
tags a redeploy dropped, so a deleted topic stops being re-subscribed forever.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Three review findings, all "unbounded work/memory from untrusted broker input"
rather than correctness bugs - but this points at a live plant broker.
1. InferPayload decoded the WHOLE payload on MQTTnet's dispatcher thread before
trimming to 64 chars. The node cap never engages here: a multi-MB blob on an
already-known topic creates no node, it just updates one, so the cost repeats
per message forever. Now at most PayloadInspectMaxBytes (512) are examined.
A blind slice can cut a multi-byte sequence, which the strict decoder would
report as "binary" - TrimToUtf8Boundary backs the window off to the last whole
sequence so good UTF-8 is never mislabelled. A clipped payload is String by
construction rather than inferred from a partial view.
2. The node cap bounded COUNT, not bytes. MQTT topics run to ~65KB, so 50k nodes
near that ceiling is a multi-GB tree. Topics now bounded at 1024 chars and
segments at 256, rejected whole (a truncated topic is a DIFFERENT topic the
picker would commit as a tag address) and surfaced via an __oversized__ marker
kept distinct from __truncated__ - the operator's remedy differs.
3. Control characters in a snippet would break the picker's single-line row;
Trim() only strips the ends. Now scrubbed to spaces.
Each guard was falsified independently by neutering it and confirming exactly one
test reddens. That found a real gap: the oversized-topic test was passing via the
SEGMENT bound, leaving the whole-topic bound untested - the test now uses many
short segments so only the topic bound can reject it.
Also records the .Driver project reference as a known, deliberate exception to the
.Browser -> .Contracts pattern, with its cost (AdminUI gains Core + Polly + Serilog)
and the clean fix (a leaf transport project; NOT a move into .Contracts, which is
deliberately transport-free).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
MqttSubscriptionManager is the P1 plain-MQTT ingest path: it holds the authored
RawPath → MqttTagDefinition table behind the shared EquipmentTagRefResolver,
establishes one SUBSCRIBE per distinct authored topic, and turns each inbound
message into a LastValueCache update plus an OnDataChange notification.
Load-bearing choices, each pinned by a falsified test:
- The published reference IS the RawPath (def.Name), never the topic and never
the TagConfig blob — DriverHostActor's dual-namespace fan-out is RawPath-keyed,
so any other key passes every unit test and delivers nothing in production.
- One message fans out to EVERY tag on its topic; several tags routinely share a
topic with different jsonPaths, and stopping at the first match silently starves
the rest.
- An unauthored topic raises nothing: MQTT ingest never auto-provisions.
- Wildcard-authored topics (accepted by the parser, warned at deploy) match via
MQTTnet's own MqttTopicFilterComparer, so '+'/'#' behave as a broker would.
Concrete topics stay a single lookup; the wildcard scan runs only when one exists.
- Retained seeds are honoured natively on MQTT 5.0 (retain handling) AND filtered
client-side on the retain flag, because 3.1.1 brokers always replay.
- Nothing throws on MQTTnet's dispatcher thread: a malformed payload degrades that
tag (BadDecodingError / BadTypeMismatch), and a throwing OnDataChange subscriber
is contained without starving the tags behind it.
- The manager issues the FIRST subscribe itself — Reconnected deliberately does not
fire after the initial ConnectAsync.
- Reconnect re-subscribe: total failure THROWS (MqttConnection then tears the
session down and retries under backoff, rather than serving a connected-but-deaf
driver); a partial SUBACK rejection degrades only the denied refs, because
retrying forever over one ACL-denied topic would take every tag dark.
MqttConnection gains a MessageReceived observer (fired on the dispatcher, throwing
observers contained) and a bounded SubscribeAsync under its own linked-CTS deadline
— deliberately not MqttClientOptions.Timeout, which already governs every MQTTnet
op. A refused filter is an outcome, not an exception; only the SUBSCRIBE itself
failing throws. Classify() is parameterised by operation name (messages unchanged
for connect).
JSONPath is a documented subset ($, $.a.b, $['a'], $.a[0]); filters/slices/
recursive descent report a miss rather than pulling in a JSONPath package for an
expression form that selects a set where a tag needs one scalar.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
A will is published by the BROKER, so it is invisible to PublishCountForTest.
MqttDriverOptions carries none today, but Sparkplug NDEATH is a will message -
once P2 adds it, an ungraceful browse disconnect would fire NDEATH under the
plant's own edge-node identity. ToBrowseOptions is where it must be cleared.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
MQTT has no discovery protocol, so the AdminUI address picker learns the topic
space the only way there is: subscribe to the wildcard and accumulate what
arrives. MqttBrowseSession serves that observation as a segment tree (split on
'/'); MqttDriverBrowser opens it with a distinct "{clientId}-browse-{guid8}"
identity under a 5-30 s clamped budget.
Browsing publishes NOTHING - the load-bearing safety property, since the picker
runs against a live plant broker. Every outbound message must route through the
single PublishAsync seam that counts into PublishCountForTest; P2's operator-
triggered Sparkplug rebirth is the one intended exception. Sparkplug mode fails
fast rather than serving a raw spBv1.0 topic tree that looks like a metric tree.
Deviation from the plan's ref list: the project also references .Driver so the
browse CONNECT reuses MqttConnection.BuildClientOptions (TLS posture, CA-pin
chain validator, credentials). A second copy would be a security divergence.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
The C1 credential-hygiene fix converted InitializeAsync and ReadAsync to
surface only ex.GetType().Name, but left HandlePollError building its
operator-facing Degrade() message from raw ex.Message, gated only by
'if (ex is DbException) return;'. That guard exists for the I1
double-classification concern, not for message safety, and it is incomplete
for the leak vector: a malformed connection string throws ArgumentException
from the keyword parser (the same unquoted-';'-in-password shape the sibling
SqlDriverBrowser.Sanitize special-cases), which is not a DbException and so
reaches Degrade(ex.Message) unredacted.
It is unreachable in today's control flow only because the connection string
is static and validated identically at Initialize first — an emergent
property, not an enforced invariant, and a live per-poll leak the moment a
future edit (refresh-on-reinit, a different provider) breaks that assumption.
Make the fallback type-only like the other two sites; the full exception still
reaches the log sink via the exception parameter. The I1 defer + control tests
are unaffected (they assert Degraded, not message text). Pinned by a new test
driving a credential-bearing ArgumentException through HandlePollError;
verified load-bearing (red against Degrade(ex.Message), green after).
Closes the C1 review finding on commit 37f444b9.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Add DriverTypeNames.Sql (+ All) as the shared source of truth, and wire the driver
into the Host: register the factory in DriverFactoryBootstrap.Register via
Driver.Sql.SqlDriverFactoryExtensions.Register(registry, loggerFactory), add the
SqlProbe (= Driver.Sql.SqlDriverProbe) probe via TryAddEnumerable, and add the
Driver.Sql project reference to the Host. Default tier A (SQL client is managed +
cross-platform, so ShouldStub needs no change).
Repoint the interim SqlDriver.DriverTypeName / SqlDriverFactoryExtensions.DriverTypeName
literals at DriverTypeNames.Sql; both still resolve to "Sql", so the AdminUI
TagConfigEditorMap/TagConfigValidator keys and the DriverTypeName-parity test stay
green. The Core guard test discovers factories from its own bin, so it also gains a
Driver.Sql project reference — that is the "registered-factory side" that lets
DriverTypeNamesGuardTests' bidirectional-parity check pass (4/4 green).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Closes the connect-vs-connect defect: MQTTnet throws (and raises no DisconnectedAsync)
on a connect-while-connected, so a caller's ConnectAsync and the reconnect supervisor
corrupted each other in both directions. Both paths now check first; when the supervisor
finds the session already restored it stands down WITHOUT firing Reconnected.
Reconnected becomes Func<CancellationToken, Task>, fed from the lifetime token and capped
at ConnectTimeoutSeconds, so a hung re-subscribe can no longer park the supervisor.
Connected is published only after the re-subscribe succeeds; a supervisor that dies now
reports Faulted instead of Reconnecting forever.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Review follow-up on the blackhole gate. Two robustness gaps, both bounded to the
disposable dedicated container (never shared infra), fixed:
- If the outer token fired while 'docker pause' was in flight, 'paused' was set
only AFTER the await, so a cancellation there left paused=false while the
container could still complete the pause — the finally then skipped unpause and
leaked a frozen container. Mark paused BEFORE the await, and make the finally's
unpause best-effort (unpausing a never-actually-paused container errors
harmlessly, and a cleanup failure must never mask the real test outcome).
- The pause/unpause shell commands had no wall-clock bound of their own — only the
post-pause read was capped — so a hung SSH handshake would hang CI. Give
RunShellCommandAsync its own 30s hard cap that kills the process and throws
TimeoutException, distinct from an operator's own cancellation.
Offline skip still clean (1 skipped, 9ms, no socket/docker).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
C1: SqlDriver's Initialize/Read failure paths no longer interpolate the ADO.NET
provider's ex.Message into LastError, the thrown message, or host status — only
ex.GetType().Name reaches the operator surface; the full exception goes to the log
sink via the structured logger's exception parameter. The driver is dialect-agnostic
over an arbitrary DbProviderFactory, so it cannot rely on any provider's message
discipline (Microsoft.Data.SqlClient's parser echoes an unrecognised keyword
lower-cased, which a value-based redactor misses).
C1a: replace the vacuous credential test (SQLite's "unable to open" message never
contains the connection string, so it passed regardless) with one that fabricates a
DbException whose own .Message carries a credential token and drives it through the
Initialize liveness-failure path via the injectable factory seam — red against the
pre-fix ex.Message interpolation.
I1: HandlePollError now ignores the DbException class ReadAsync already classified,
so a subscribed-read outage is classified (and logged) once, not twice with the
worse message.
I2: the poll's Healthy verdict routes through a shared SetHealthUnlessFaulted guard
(the one Degrade already used), so a late in-flight poll cannot un-fault a driver a
concurrent ReinitializeAsync just faulted.
I3: DiscoverAsync warns when materializing an omitted-type tag as String, the only
operator signal for the declared-vs-published type mismatch on a numeric column.
M1: BuildTagTable wraps the per-entry parse so a stray non-JsonException throw skips
the tag instead of stranding health at Initializing (it runs before Initialize's
try/catch). M2 left as a documented TODO to avoid touching SqlPollReader.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
SqlTagConfigModel + SqlRowSelectorModel mirror SqlEquipmentTagParser's
accept/reject boundary byte-for-byte on the fields they own: model/type
serialize as NAME strings (never numbers), KeyValue requires
table+keyColumn+keyValue+valueColumn, WideRow requires table+columnName+a
selector (where-pair OR topByTimestamp), Query is rejected, and unknown keys
(top-level and nested rowSelector) survive load->save. Registered in
TagConfigEditorMap + TagConfigValidator keyed off SqlDriver.DriverTypeName
(DriverTypeNames.Sql is deferred to Task 11). A minimal placeholder
SqlTagConfigEditor.razor lands the map entry now; Task 20 fleshes out the UI.
The load-bearing test rounds editor output back through
SqlEquipmentTagParser.TryParse (editor-output <=> parser-input agreement).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Its doc said it pinned "the real provider's cancellation path", but the
token is cancelled before ReadAsync so the OCE is raised at the reader's
SemaphoreSlim.WaitAsync gate, before any SqlConnection opens — it never
exercises Microsoft.Data.SqlClient's in-flight command cancellation.
Softened (option (a)) to state accurately what it proves: an already-
cancelled token propagates as OCE and is never swallowed into a Bad
snapshot or an unreachable-database verdict. The in-flight/deadline path
is covered by SqlBlackholeTimeoutTests.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Adds the frozen-peer / BadTimeout gate for the Sql driver — the single
highest-value integration test. Mirrors the S7 R2-01 blackhole gate:
docker pause a DEDICATED mssql mid-poll, assert the next read surfaces
BadTimeout within the client-side operationTimeout (≈3s) and well below
the server-side CommandTimeout backstop (30s), the driver degrades
(Degraded + host Stopped), and docker unpause recovers to Healthy/Running.
- Docker/docker-compose.yml: disposable `otopcua-sql-blackhole` mssql on
:14333 (never the shared :14330 ConfigDb server) + one-shot seed.
- Docker/seed.sql: the two sample tables.
- SqlBlackholeTimeoutTests.cs: env-gated (SQL_BLACKHOLE_ENDPOINT); pauses
ONLY the hard-coded container name; skips loudly if the endpoint is the
shared port 14330; bounds its own wait so a wedged impl fails, not hangs.
Offline: clean skip (no socket, no docker shell-out).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Locks the driver's injection guarantee against the SQLite fixture. An
authored VALUE ('; DROP TABLE TagValues; --) binds as a DbParameter and can
only ever be a key that matches no row (BadNoData); the seed table survives.
A hostile IDENTIFIER in table/column position is dialect-quoted into a
single nonexistent identifier — inert — and the payload never executes.
Scope, stated plainly: design §8.1 also specifies a catalog gate (validate
an authored identifier against INFORMATION_SCHEMA, reject an unknown one as
BadNodeIdUnknown). That gate does NOT exist in the driver yet and no task
here builds it, so a hostile identifier is not rejected up front — it is
quoted, the query fails after the connection opened, and the tag Bad-codes
as a query failure (BadCommunicationError), not BadNodeIdUnknown. These
tests assert what the code actually guarantees — the payload is inert and
the table intact — rather than a catalog gate that isn't there. The gate is
a tracked follow-up.
No implementation change: the reader already binds correctly (Task 7); this
suite pins it. Falsifiability-checked — forcing a real DROP before the
row-count assertion turns it red, so "table survives" is load-bearing.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Register SqlDriverBrowser as an IDriverBrowser beside the OpcUaClient/Galaxy
lines, project-reference Driver.Sql.Browser, and add SqlAddressPickerBody.razor:
a DriverBrowseTree schema/table/column picker (DriverOperator-gated) with a
column attribute side-panel, manual-entry model/selector fields retained, that
composes the per-tag TagConfig blob (KeyValue / WideRow) matched to
SqlEquipmentTagParser. Pasted ad-hoc connection strings are session-only and
never persisted into the composed blob or driver config.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
The AdminUI "Test Connect" probe for the Sql driver: open a connection, run
the dialect's LivenessSql (SELECT 1) under a linked-CTS deadline, return
green with latency or red with a reason. Implements IDriverProbe; never
throws (malformed JSON, missing connectionStringRef, unprovisioned
connection string, a provider open failure, timeout, cancellation all
become red results).
Parses the SAME factory DTO with the SAME JsonStringEnumConverter as
SqlDriverFactoryExtensions (R2-11 factory parity, mirroring
ModbusDriverProbe) and resolves connectionStringRef the same way, so a
config that Test-Connects is the config that Deploys.
Credential hygiene: the resolved connection string never reaches the result
message. A provider exception can embed the data source in its OWN message
(the real SqlException shape), so the catch-all names the exception TYPE
only, never ex.Message. The regression test's fake connection embeds the
connection string in its thrown message specifically so surfacing ex.Message
would leak it — verified load-bearing by breaking the guard and watching it
go red.
ForTest injects factory+dialect for the offline SQLite fixture path.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
SqlDriverFactoryExtensions turns a deployed DriverConfig blob into a live
SqlDriver, and SqlConnectionStringResolver resolves the authored
connectionStringRef NAME from Sql__ConnectionStrings__<ref> so credentials
never ride in a config blob (design §8.2).
Three behaviours worth naming:
- String-enum guard. JsonOptions carries JsonStringEnumConverter +
camelCase, so `provider` parses whether authored as a name or an ordinal
and always round-trips as the NAME — the systemic AdminUI defect where a
page serialised an enum numerically against a string-typed DTO.
- Config validation lands here because nothing below does it.
operationTimeout must be STRICTLY greater than commandTimeout (design
§8.3); the reader and the driver stay deliberately usable with the pair
inverted so the frozen-database tests can prove the client-side bound
fires. Non-positive timeouts / poll interval and maxConcurrentGroups < 1
are rejected too.
- Credential hygiene. The resolved connection string reaches the provider
and nothing else: messages name the ref, the environment variable, or
SqlDriver.Endpoint's credential-free server/database rendering. Both a
log-leak and an exception-leak test cover it.
DTO changes:
- Adds RawTags (List<RawTagEntry>), following the Modbus precedent — the
deploy artifact delivers a driver's tags this way and the DTO had no way
to receive them, so an authored Sql tag could never reach the driver.
- Deletes SqlProbeDto + the `probe` key. It had no consumer: SqlDriver was
specified without a background probe loop, and deliberately so — its
IHostConnectivityProbe state is a by-product of the Initialize liveness
check and of every poll, i.e. a statement about traffic that actually
happened rather than a synthetic ping. On-demand connectivity is Task
10's SqlDriverProbe. Shipping a config key that silently does nothing is
worse than not shipping it; UnmappedMemberHandling.Skip means a blob that
still carries `probe` keeps parsing.
allowWrites stays inert (SqlDriver implements no write capability) but an
authored `true` now WARNS rather than passing silently — the flag cannot do
harm, an operator who believes writes are enabled can.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Opens one transient DbConnection from a form-supplied driver-config blob and
hands ownership to SqlBrowseSession, which closes it on disposal. A database is
named either by connectionStringRef — resolved in the AdminUI process from
Sql__ConnectionStrings__<ref>, with an unresolvable ref naming the exact missing
variable — or by a pasted, session-only literal. The literal wins and the ref is
then not read; it cannot arrive from a persisted blob (SqlDriverConfigDto has no
such property), so its presence proves an operator typed it now.
Credential hygiene is the point of the type: no cached config field, nothing
persisted, and no connection text in any log line or exception. Live-probed:
Microsoft.Data.SqlClient and Microsoft.Data.Sqlite keep connection-string values
out of SqlException/SqliteException, but their connection-string PARSER echoes an
unrecognised keyword verbatim — and an unquoted ';' inside a password splits, so
the tail of the password is reported as a keyword (Password=Sup3r;SecretTail =>
"Keyword not supported: 'secrettail;connect timeout'."). The parser's message is
therefore never surfaced; every other failure additionally passes through a
substring redactor that drops the inner exception when it fires.
DriverType comes from SqlDriver.DriverTypeName, the driver's interim local
constant — DriverTypeNames.Sql is added by the driver-factory task.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Three review findings against SqlPollReader (967e5140).
1. WideRow's where-pair form emits no ORDER BY and no row limit, so a
selector that is not actually unique made the reader publish an
arbitrary, storage-order-dependent row — silently, unlike IndexByKey's
duplicate-key warning. Row selection moves out of MapMember into a new
SelectWideRow, which is called once per group and emits the same
rate-limited contract warning (naming table, selector and row count).
The row-limit half of the suggested fix was deliberately NOT taken: a
TOP 1 with no ORDER BY is not deterministic either, and it would
destroy the Rows.Count > 1 evidence the warning depends on, turning a
loud misconfiguration into a permanently silent one. Rationale is in
SelectWideRow's docs. No SQL changed, so no planner golden string moved.
2. The "a frozen database can never accumulate more than
maxConcurrentGroups connections" claim was asserted in the docs and
untested. ReadAsync_aTimedOutGroupKeepsItsConcurrencySlotUntilTheQuery-
TrulyFinishes wedges a group behind an EXCLUSIVE transaction, times it
out, and proves the slot is still held (a second poll on a cap of 1
times out on the gate without ever reaching the factory) and is handed
back only once the abandoned query truly finishes. Moving the release
from the work to the waiter fails this test and no other.
3. Task.Run thread-pool starvation: documented, not changed.
Microsoft.Data.SqlClient's async path parks no pool thread on a frozen
server, so the driver cannot starve itself; LongRunning would cost a
dedicated OS thread per group per poll forever to insure against a
provider this driver does not ship. RunGroupAsync now records the
decision and what a BadTimeout does and does not mean, for the
blackhole gate.
Also: the timeout warning now names the group's table, so a BadTimeout
storm identifies which source is frozen.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Walks schemas -> tables/views -> columns via ISqlDialect's catalog SQL, with
@schema/@table bound as parameters at every level. Column leaves carry the
dialect-mapped DriverDataType in the attribute side-panel (ViewOnly, read-only
v1).
The NodeId encoding deliberately departs from the design sketch's literal
`schema.table|column`: SQL Server permits `.` and `|` inside a quoted
identifier, so that form mis-parses (main.a.b|c reads equally as schema
`main`+table `a.b` and schema `main.a`+table `b`) and silently binds an
operator's tag to the wrong column. SqlBrowseNodeId encodes
`<kind>:<part>[|<part>...]` with `\`/`|` escaped and the kind prefix carrying
the arity; it is public because the picker body decodes it back.
The session owns the connection it is handed and closes it on dispose -- the
registry-held session is the only lifetime hook, so a non-owning session would
leak one pooled connection per reaped picker. Per-call work stays bounded by
the AdminUI's existing 20s linked CTS (BrowserSessionService.PerCallTimeout);
no second deadline is invented here.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
SqlDriver implements IDriver / ITagDiscovery / IReadable / ISubscribable /
IHostConnectivityProbe / IAsyncDisposable over the landed SqlPollReader,
mirroring ModbusDriver. IWritable is deliberately absent: v1 is read-only
structurally, and every discovered variable is SecurityClass=ViewOnly.
The shell classifies poll outcomes because nothing below it does. The reader
honours IReadable literally — it throws only when the database is unreachable
and Bad-codes everything else — so a frozen database returns all-BadTimeout
snapshots through a perfectly successful PollGroupEngine tick. Without
ObservePollOutcome the driver would report Healthy while every value was Bad.
Connection-class codes (BadTimeout / BadCommunicationError) degrade health and
report the host Stopped; authoring-class codes (unresolvable RawPath, absent
row, type mismatch) change nothing, so a tag typo never reports the database
down. It deliberately does NOT synthesise an exception to earn engine backoff:
the engine's exception path publishes nothing, which would cost clients the
Bad quality the reader went out of its way to produce.
Initialize builds the authored RawPath table first (pure, cannot fail; a
malformed TagConfig is logged and skipped) then verifies liveness over one
open-use-dispose connection bounded by wall clock as well as by token (the
R2-01 lesson) — failure records Faulted and rethrows so DriverInstanceActor
retries. The connection string is never logged: a credential-free
server/database Endpoint is the only rendering that reaches a log, LastError,
or the host status.
DriverTypeNames.Sql is NOT added here — DriverTypeNamesGuardTests asserts
bidirectional parity with registered factories, so the constant must land with
the factory (Task 11). SqlDriver.DriverTypeName carries the string until then.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
LastValueCache bridges MQTT's subscribe-first push model to the OPC UA
server's polled IReadable.ReadAsync: the subscription path calls Update()
per RawPath, the read path calls Read(). Read never throws; an unseen
RawPath returns BadWaitingForInitialData (0x80320000) rather than an
exception or null, so a batch covering many references degrades per-ref
instead of failing wholesale.
Deviates from the plan's GoodNoData snippet: GoodNoData is reserved
repo-wide for "the historian window held no samples" (NullHistorianDataSource,
OtOpcUaNodeManager HistoryRead paths); BadWaitingForInitialData is the
established convention for "no live value observed yet" (CalculationDriver,
VirtualTagEngine, FOCAS, AddressSpaceApplier). Keyed by RawPath per the v3
driver-reference identity, not a topic/JSON-path-derived key.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Review follow-ups on MqttConnection (Task 3):
- Every certificate test asserted rejection, so the accept branch was
unreachable-by-regression. Adds a leaf genuinely issued by the pinned CA and
asserts acceptance.
- ValidateAgainstPinnedCa never seeded ChainPolicy.ExtraStore from the incoming
chain, so a leaf behind an intermediate delivered during the handshake failed
despite a legitimate path to the pinned root. Seeds from both the incoming
chain's elements and its ExtraStore; CustomRootTrust still means only the
pinned roots may terminate the chain.
- A DisposeAsync racing an in-flight connect escaped as an unclassified
exception; it now folds into ObjectDisposedException.
- Promotes the single-caller concurrency invariant into the type remarks, with
the accurate blast radius (a leaked live connection, not a benign throw).
Serialising the lifecycle remains Task 4's job.
- X509Chain.Build can throw; an exception escaping a TLS validation callback is
an opaque handshake crash, so it is caught and refused.
- Adds a connect-retry test (Task 4's reconnect loop reuses the instance) and a
disposed-then-connect test.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Task 2 review follow-up. The plan specified MqttEquipmentTagParser.TryParse(reference)
with def.Name = the TagConfig blob, and told us to mirror a type named
ModbusEquipmentTagParser. Both are plan defects:
- EquipmentTagRefResolver documents that a v3 driver reference "is now always a
RawPath" and that the blob-parse fallback is retired. Keying Name by the blob
would make OnDataChange publish under a reference that never matches the
RawPath-keyed fan-out in DriverHostActor - silently dead in production with
every unit test still green.
- ModbusEquipmentTagParser does not exist. The six sibling drivers all use
<Driver>TagDefinitionFactory.FromTagConfig(tagConfig, rawPath, out def).
Changes:
- Rename MqttEquipmentTagParser -> MqttTagDefinitionFactory; TryParse(reference,
out def) -> FromTagConfig(tagConfig, rawPath, out def) setting Name: rawPath,
matching ModbusTagDefinitionFactory's structure, param docs and guard order.
- Pin the identity contract with a dedicated test so a regression to blob-keying
goes red.
- Read qos with the same strictness as the enums: a present-but-invalid qos
("high" / 1.5 / 5 / null) now rejects the tag and is warned by Inspect,
instead of being silently absorbed into the driver-level default and handing
the operator a weaker delivery guarantee than the one they authored.
- No ToTagConfig inverse: the siblings carry one solely for their Driver.<X>.Cli
project, the MQTT plan defines none, and the AdminUI editor template
references no driver factory. Recorded as an explicit YAGNI call in the type
doc rather than added speculatively.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Code-review Minor: the record typed ParameterNames/Parameters/Members/
SelectedColumns as IReadOnlyList<T> but was handed the planner's live List<T>
instances. SqlQueryPlan documents itself as safe to hold for plan caching, so
an aliased list is a real hazard once the reader starts reusing plans across
polls: IReadOnlyList<T> is downcastable, and one mutation would corrupt every
subsequent poll served by that plan.
Copying at the record boundary fixes it for every call site at once rather
than relying on each planner branch remembering to call AsReadOnly.
Pinned by a test that mutates the caller's lists after construction; verified
load-bearing (reverting the record turns it red).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Executes a poll pass: resolve refs -> SqlGroupPlanner.Plan -> one command per
group -> slice the result set back to per-tag DataValueSnapshots, positionally
aligned with the caller's reference list (design §3.2).
The frozen-peer contract (design §8.3, the R2-01 S7 lesson) is the core of it.
CommandTimeout is only the server-side backstop; the client-side bound is a
linked CancelAfter PLUS Task.WaitAsync, because a linked token bounds only a
provider that honours it and ADO.NET providers vary. The whole per-group
operation — waiting for a concurrency slot, OpenAsync, and the query — runs off
one operationTimeout budget, so ReadAsync returns on time regardless of what the
database is doing. A breach Bad-codes that group (BadTimeout); caller
cancellation propagates instead, since nobody consumes a torn-down poll.
Also: absent row (BadNoData) stays distinct from a NULL cell (Uncertain, or Bad
under nullIsBad); duplicate plan members are all fed (two tags on one keyValue
bind one parameter but stay two members); the concurrency slot is released by the
work, not the waiter, so a frozen database can never hold more than
maxConcurrentGroups connections; the whole call throws only when the connection
itself cannot open, which is what earns PollGroupEngine's backoff.
SqlStatusCodes is driver-local, matching every sibling driver's own table — there
is no shared helper in Core.Abstractions and drivers do not reference the OPC UA
SDK. Values were read off Opc.Ua.StatusCodes rather than copied from a sibling,
because two of those tables carry transcription errors.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Joseph Doherty