G19 BUILT and PASSED LIVE; finds a latent defect in D-139's execution list ...

scripts/dc-node-v6-verify.sh (270 lines, 24-line header) + tests/dc-node-v6-verify
(55 cases); manifest 95 -> 96. All three subcommands exercised LIVE this session:
plan vr1-dc0 PASS exit 0 (9 machines, v6 plane set IDENTICAL across all 9, 6
planes, prefixes DERIVED); node vr1-dc0 <spec> on storage-01 against live peer
storage-02 PASS exit 0 with 12 assertions -- six address-presence, six
peer-reachability, every plane "up, global, DAD complete, sole global on the NIC"
and "replies, neighbour DELAY"; bridges vr1-dc0 reporting 7 bridges. Harness
55/55, gauntlet ALL GREEN (96), three mutations each turning a NAMED test red.
RUN AGAINST A REAL NODE while the boot window was open specifically so it would
not ship fixture-green -- the snap proxy's harness was green for a week before
anything was proven end to end.

NO v6 PREFIX LITERAL EXISTS IN THE FILE, and that was a constraint not a nicety:
D-139 retires the ULA /48 for GUA, so a baked table would be right today and wrong
on carve day. plan derives from live MAAS and emits a SPEC; node consumes it and
knows no prefixes. A harness case drives the same green path with a ULA fixture
AND a GUA fixture, so the property is EXECUTED, not asserted.

>>> LATENT DEFECT IN D-139's OWN EXECUTION LIST <<<
D-139 names dc-node-v6-carve.py to "re-carve 54 node v6 statics". VERIFIED against
that script's source: it assigns v6 "on every plane WHERE IT ALREADY CARRIES
IPv4", picks the v6 subnet "on the SAME MAAS vlan as that v4 link", derives the
host part from "the last octet of the node's own v4 address", and its loop body is
a bare `if not v4: continue`. Under D-139 five planes lose v4 and lb-mgmt never
had a v4 twin, so after v4 removal it would SILENTLY CARVE FOUR FEWER PLANES PER
NODE rather than fail. The v6 carve MUST run BEFORE v4 removal, or the tool must
be rewritten -- compounding the already-recorded fact that D-139's "remove v4
LAST" clause is unsatisfiable. LOGGED, NOT FIXED. My own agent mandate stated this
tool's input source WRONGLY (apex/D-136; it is live MAAS); the agent checked
rather than inheriting the error, which is why the defect surfaced.

THREE MORE FINDINGS: (i) the multicast reading is ESTATE-WIDE -- all six plane
bridges plus the WAN bridge at snooping=1/querier=0 on dc0 AND dc1, and the
jumphost's uplinks too, i.e. the default here, not a chosen setting; the
subcommand tags it SUSPECT and asserts no Linux behaviour, correctly, since
cold-start multicast ND was already measured working across it. (ii) plan's PEER
SELECTION IS DEPLOYMENT-BLIND -- it picked control-01, which is not deployed, so
the derived SPEC cannot pass in a PARTIAL deployment; worked around by
substituting the live peer, logged not fixed. (iii) a harness bug caught by the
instrument-currency rule, NINTH of its kind: absent-ip/absent-virsh REFUSE cases
were driven with PATH=/usr/bin:/bin, which still contains both, so they were red
for the WRONG REASON.

TWO OPEN CHECKS SETTLED on the live nodes: every NIC carries exactly ONE global
(sole-global predicate holds today), and an OVS-internal br-ex does report
LOWER_UP (predicate safe).

GA-R2: the build agent wrote its own changelog; folded VERBATIM into this
session's single changelog and removed. Crossing midnight does not start a new
session. repo-lint 0 fail.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf