Files
amethyst/quartz/src/commonTest
Vitor PamplonaandClaude Opus 4.8 62440748a7 fix(concord): stop a rejected edition orphaning the honest ones after it
An unauthorized control edition in the middle of an entity's chain
permanently froze that entity. Observed on device for a member's GRANT:

    v0 owner    (grant mods)
    v1 owner    (grant admins)     <- fold stopped here, forever
    v2 MIDTIER  (escalation, correctly rejected)
    v3,v4,v5 owner                    orphaned, unreachable

`AuthorityResolver` filtered unauthorized editions out BEFORE calling
`EditionFold.foldEntity`, and the walk only advances when the next
version cites the current head's hash. Removing v2 severed the chain, so
every honest edition above it was lost. Any member could permanently
freeze any member's role assignment — including the owner's ability to
change it — with a single event, recoverable only by a Refounding. It
predates the recent rank gates (verified with a zero-role identity); the
gates only widen which editions can poison.

Armada does not have this bug, and its approach settles the design.
Reading its control-plane fold (read for semantics only — Armada is
AGPLv3, Amethyst is MIT, no code taken): the chain walk runs over the
UNFILTERED set, producing an ordered candidate list — chain-verified head
first, then every remaining edition version-descending — and authority is
applied AFTERWARDS, per candidate, picking the first admissible one. A
rejected edition is skipped during the ascending admissibility walk
without truncating it. For the chain above, Armada picks v5.

So the fix is not to filter later but to gate later: `EditionFold` gains
candidate-based gated folding, and the resolver and community state now
gate per candidate instead of pre-filtering the pool. Authority checks
themselves are unchanged — only WHEN they run moved. Applied to ROLE,
GRANT, BANLIST, CHANNEL, METADATA and the authorized-head map.

The writer had to be fixed too, for a sharper reason than expected. With
an ungated `headOf`, a rogue banlist edition at the tip is read as
current state, so the owner's next ban REPUBLISHES THE ROGUE'S CONTENT
UNDER THE OWNER'S SIGNATURE — an unauthorized empty banlist laundered
into an owner-signed one the moment the owner bans anyone else. Tolerant
reading cannot heal that, because the resulting edition is genuinely
authorized. `ConcordModeration.headOf` now folds the authority-gated
heads, and `owner` is a REQUIRED parameter rather than defaulted, since a
silently-wrong default here is a consensus footgun.

Banlist healing is preserved with one necessary change: the ancestry walk
now runs over the full pool rather than the authorized subset. Ancestry is
structural — walking only authorized editions stops at the rejected one
and misreads genuine ancestors as concurrent forks, resurrecting bans an
unban had cleared.

Six regression tests, each verified to fail without the fix. Two process
notes worth recording: the first "without the fix" run reported BUILD
SUCCESSFUL because Gradle served a stale up-to-date `jvmTest` — trusting
it would have meant concluding the tests were worthless. And the
forged-edition test initially passed both ways because the forgery's
content coincided with the honest outcome; it was rewritten so the
mid-chain arm genuinely discriminates.

The rank-gate, rogue-higher-version, floor and rollback tests all pass
unchanged.

Known gap: `headOf` gates through the per-kind permission map, which is
coarser than the resolver's rank gates, so the writer can still pick a
head the reader rejects when an in-permission but out-of-rank edition
sits at the tip. Tolerant reading makes that benign, but it is not an
exact reader/writer match; tightening it needs the resolver to expose
per-entity heads.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-20 09:06:13 -04:00
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