D-139 ruling B's deciding reason REFUTED by measurement; ruling FLAGGED ...

Closing the unverified premise D-139 named at ruling time inverted its own
argument. Recorded, flagged for operator reconsideration, NOT amended.

MEASURED, two steps:
 1. jammy libc-bin 2.35-0ubuntu3 ships /etc/gai.conf with ZERO active lines --
    every line commented. The node image applies NO override, so glibc's
    compiled-in table governs.
 2. glibc 2.35 default_precedence[], fetched in full from sourceware at tag
    glibc-2.35 and read rather than recalled, carries glibc's OWN comment
    "See RFC 3484 for the details" and is:
      ::1/128 50 | 2002::/16 30 | ::/96 20 | ::ffff:0:0/96 10 | ::/0 40
    THERE IS NO fc00::/7 ENTRY IN THE PRECEDENCE TABLE.

CONSEQUENCE: ULA falls through to ::/0 = 40, identical to GUA; IPv4-mapped is
10. So on the node image ULA = GUA = 40 and BOTH outrank IPv4. Ruling B was
declared on "ULA loses to IPv4 (3 vs 35), GUA wins (40 vs 35)" -- the RFC 6724
table. RFC 6724 obsoletes RFC 3484 and does define those values, but glibc 2.35
DOES NOT IMPLEMENT IT. Right about the RFC, wrong about the software this cloud
runs. The fc00::/7 entry that does exist is in default_labels[] (label 6), which
drives SOURCE selection rules 5/6 -- a different mechanism, recorded so the two
are not later conflated into "the argument stands after all".

A NEW VARIANT OF THE CITATION CLASS, worth naming: the citation was real,
current and correctly quoted, and still wrong here because nobody checked
whether the IMPLEMENTATION follows the RFC. Checking a source's status and dates
is not sufficient for a standards citation.

SURVIVING REASONS (independent of the refuted one): conformance with Willamette
(a real site) and VR0 DC0, both full GUA; and MINIMIZE DELTA TO ROOSEVELT, whose
2602:f3e2:103::/48 is GUA with no ULA and no plane carve yet. The ruling may well
stand on these -- but under GA-R5 that is the operator's call, since they
answered a question whose stated deciding reason no longer holds.

D-139's text is UNCHANGED. Nothing of D-139 is executed, so nothing is half-built
in either direction. repo-lint 0 fail.

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

D-139 ADOPTED: VR1 goes IPv6-only east-west, whole carve moves to GUA ...

TWO GA-R5 rulings, taken in SEPARATE exchanges, recorded separately.

A -- family matrix. Operator: "IPv6 on all planes except for metal-admin and
provider-public which will remain dual stack". metal-internal, data-tenant,
storage, replication and lb-mgmt become IPv6-ONLY. Amends D-101's matrix twice:
metal-internal's "datastore east-west stays v4-bound" is superseded, and lb-mgmt
(ruled v6-only by D-101 but NEVER carved anywhere) becomes a first-class plane.

B -- addressing model. Operator: "Full GUA on every plane (Recommended)". Every
plane carves from its DC's GUA /48 on the :10/:11/:20/:21/:30/:40/:50/:80 octet
map VR0 DC0 and the Willamette site ALREADY use -- conforming to an existing org
standard, not inventing one. The ULA /48 fd50:840e:74e2::/48 is RETIRED for VR1.
Amends D-101 and D-111. Deciding reason is measurable: RFC 6724 ranks IPv4-mapped
at precedence 35 and ULA at 3 while GUA falls under ::/0 at 40, so on a dual-stack
plane a ULA leg LOSES address selection to IPv4 and is decorative. SEC-010, D-052,
D-125 and D-107 unchanged -- containment lives at the forwarding layer.

THE RECORDED ROOT CAUSE OF THE v4-ONLY CONTAINERS WAS WRONG AND THIS REPO CARRIED
IT (GA-R1 C2 -- measurement corrects the document). CURRENT-STATE said MAAS "has
nothing to give for v6". Measured, and re-verified independently: subnet
statistics on fd50:840e:74e2:220::/64 returns available_string "100%",
num_available 18446744069414584320. Zero ipranges rows means zero RESTRICTIONS,
not zero availability. dc-plane-ipam.sh:368-372 has carried the correct behaviour
since 2026-07-27, in the tree, contradicting the authoritative doc the whole time.

The real mechanism is juju-side and there is NO knob: EthernetDeviceForBridge
(tag v3.6.27) takes addrs[0] from an UNSORTED query and derives one CIDR -> one
LinkSubnetArgs. gomaasapi documents "Any number of STATIC links can exist on an
interface", so MAAS would accept both families; the limit is juju's. LP #1723240
is this exact symptom, Triaged/Low since 2017, and the theory this repo recorded
is the one its reporter rebutted in-thread. Consequence: on a container plane
DUAL-STACK IS NOT EXPRESSIBLE while v6-only IS -- ruling A is the achievable
configuration, not merely the desired one.

SNAP PROXY: dc0 INSTALLED, RUNNING, check dc0 PASS exit 0 (16 assertions,
re-verified independently). A REAL SNAP PAYLOAD WAS FETCHED THROUGH IT -- HTTP 206,
first bytes hsqs. No longer fixture-green. BUG-3 confirmed by measurement, no
assertion changed. BUG-4 fixed at BOTH sites (the review named one); T20b/T41b NEW.

OWNED: my BUG-1 fix was WRONG. ip route get 10.12.8.4 -> src 10.12.8.2; .4 is a
SECONDARY and Linux never auto-selects a secondary as a source, so the rule is
still dead. Not fixed now -- editing the generator turns the LIVE gate red until
install re-runs. T23b annotated so nobody "fixes" the test to a wrong value.
Generalisable: any ACL keyed to a service ALIAS (the whole D-134 utility .4 band)
misses that host's own traffic -- same exposure in dc-mirror.sh, dc-cache-proxy.sh.

OWED, unverified: the deployed jammy /etc/gai.conf, which can override the RFC 6724
default table that ruling B rests on. Nothing of D-139 is executed.

repo-lint 0 fail; tests/dc-snap-proxy 55/55; 4 mutations killed.

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