RediscoverPolicy is now mode-dependent: UntilStable in Sparkplug B (a tag's
dataType is optional -- the birth certificate declares it, so the discovered
tree fills in asynchronously), Once in Plain (nothing about the authored set
arrives on the wire).
DiscoverAsync resolves each Sparkplug tag's datatype per pass from the live
BirthCache, with the ingest path's own precedence: authored dataType wins,
else the birth's, else the record default. An unsupported Sparkplug type
(DataSet/Template/PropertySet/Unknown) falls back rather than blanking the
tag. The authored tag SET is never conditional on a birth -- an authored tag
is part of the declared configuration, not something the plant grants by
publishing.
SparkplugIngestor.BirthObserved is wired to RaiseRediscoveryNeeded behind a
two-part change gate, which is the anti-storm mechanism rather than an
optimisation: fire only for a scope an authored tag binds, and only when the
birth's metric-name SET (ordered-distinct, ordinal) differs from the last one
seen for that scope. Edge nodes re-birth freely -- on their own timer, on
every reconnect via the late-join rebirth fan-out, and once per rebirth NCMD
the gap policy sends -- and firing on each of those would make a healthy plant
a permanent address-space-rebuild loop. No extra debounce: what survives the
gate is a real edit to the served tree, and delaying it would need its own
trailing-edge flush to avoid dropping the last change.
The signature map is NOT cleared on death/reconnect/ingest rebuild (the
ingestor drops its whole birth cache on reconnect, but "the driver forgot" is
not "the address space changed"); it is pruned when a redeploy stops
authoring a scope.
ScopeHint is the "Mqtt" discovery folder, deliberately not the Sparkplug scope
path the plan named: the discovered tree is flat, so an edge-node/device path
would name a subtree that does not exist and a consumer scoping a rebuild on
it would rebuild nothing. The scope is carried in Reason instead.
Falsifiability: always-fire reddens the identical-rebirth + reordered-rebirth
pins; always-authored-datatype reddens the birth-fill pin; dropping the
authored-scope filter reddens the unauthored-device pin. 524/524 MQTT unit
tests green (was 513).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Joseph Doherty
6917d8805d