A wildcard writeTopic was published verbatim. MQTT-3.3.2-2 forbids a wildcard in a
PUBLISH topic and a conformant broker answers a protocol violation by closing the
connection — which for this driver is the one connection every subscription lives
on, so a single write to a mis-authored tag took the whole driver dark. The
Sparkplug side had the same hole plus a worse one: the binding tuple IS the
NCMD/DCMD topic, so a '/' in groupId/edgeNodeId/deviceId silently addressed a
different edge node than the tag names.
MqttWriteEncoder now refuses both as NoWriteDestination (-> BadNotWritable); the
read path is untouched. metricName is exempt on purpose — it rides in the payload
and Sparkplug's own canonical names use '/'.
MqttTagDefinitionFactory.Inspect gained the matching ADVISORIES (never rejections
— the mappers accept these blobs, and the gate must never be stricter than the
runtime). Both rules were already hard errors in the AdminUI's typed editor, but
that is one authoring path of several: the raw-JSON textarea, CSV import and the
API all reach the deploy gate directly, so the authoring surface was stricter than
the gate — the drift class the #549-#559 arc exists to close.
Shared shape rules single-sourced in the new internal MqttAddressRules.
Driver.Mqtt.Tests 724 (was 708); AdminUI.Tests 1466; ControlPlane.Tests 261.
Joseph Doherty
6eace4bbba