Self-review of the commit before this one caught a defect in the contract it
published rather than in the code it ran. AcceptBirth's doc said it records
"a birth (NBIRTH/DBIRTH)". That is wrong on both halves of this type, and the
wrong version plants exactly the defect the bdSeq tie exists to prevent.
Only the NBIRTH restarts the Sparkplug sequence; a DBIRTH carries the next
number in the edge node's ongoing stream, so it belongs to Accept. And only
the NBIRTH and NDEATH carry bdSeq at all -- a DBIRTH has none to pass. So a
Task 21 that followed the old doc and routed a DBIRTH to AcceptBirth would do
two wrong things at once: rebase the sequence mid-stream, and wipe the node's
session token to null. A stale Last Will arriving afterwards would then find
nothing to compare against, fall through the deliberate fail-toward-stale
rule in IsDeathForCurrentSession, and kill the live node.
Renamed AcceptBirth -> AcceptNodeBirth so the DBIRTH call site reads wrong at
a glance rather than only in prose, documented the hazard on both methods,
and added DeviceBirth_ContinuesTheNodeSequence_AndLeavesTheSessionTokenAlone
to pin the shape at this type's own boundary -- the ingest state machine now
has something to fail against if it wires the call sites the other way round.
Falsifiability: mutating Accept to clear _birthBdSeq reddens exactly the new
test (1 RED), reverted. 29 tests, 438/438 for the MQTT suite.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Joseph Doherty
3fdf24659f