# STATE-WP-0079 D2 dual-read cutover evidence — 2026-08-31

## Outcome

The Railiance Fabric authority snapshot is active on the `railiance01` State
Hub read model and the executable fin-hub parity gate is green. Import
idempotency and production rollback/roll-forward were exercised against
retained immutable imports.

This completes the D2 dual-read evidence. It does not authorize retirement of
State Hub or claim a hosted Railiance Fabric owner service; that operational
residual is `RAIL-FAB-WP-0028`.

## Authority snapshot

- Producer: `railiance-fabric`
- Contract: `railiance.fabric/v1alpha2`, `financial-fabric-v1`
- Revision: `snapshot-set:sha256:991bca294474e76a65e28011d813aace15d040aa7c173fcf8874a5d548aa7b35`
- Source path: `registry://accepted-snapshots`
- Exported at: `2026-08-31T20:44:15Z`
- Content hash: `caae66795ce8e969b086609f7905c129206e4a027eb60c65086fc183e88613a2`
- Counts: 131 nodes, 117 edges, 2 actors, 1 fabric, 0 unresolved references
- State Hub import: `47e5358e-d04b-4969-99a2-ca88423ad054`

## Compatibility defect and deployment

The first production import correctly failed closed, but exposed two receiver
defects: the Pydantic receiver omitted the contract's `deployment_overlay`, and
`fabric_graph_imports.source_commit` was `varchar(80)` while deterministic
snapshot-set revisions are 84 characters. The invalid-import diagnostic then
also hit that width constraint and returned HTTP 500 instead of 422.

State Hub commit `cf40c7b` aligned the receiver, bounded invalid provenance
metadata, added migration `b5e6f7a8c9d0`, and added regression coverage. It was
deployed atomically as image `main-cf40c7b`, Helm revision 56. Commit `cdff3b7`
then added immutable-import activation for operational rollback and was deployed
as image `main-cdff3b7`, Helm revision 57. Final health reported
`primary/railiance01`, database connected, and schema `b5e6f7a8c9d0` applied.

Verification:

- Full State Hub suite before the first deployment: 828 passed; dashboard build
  completed (one pre-existing SQLAlchemy resource warning and one broken-link
  warning).
- Focused activation/financial/import tests after the rollback addition: 5
  passed.
- The exact saved authority payload validated as 131 nodes / 117 edges before
  deployment.

## Parity and idempotency

`finhub fabric-cutover-check` compared the saved authority export with
`/fabric/graph/summary`. All checks passed: API/schema/kind, content hash,
node/edge/actor/fabric/unresolved counts, source revision/path, and export time.
The result was `ready: true` with no failures.

Posting the identical saved payload a second time returned `created: false`,
`idempotent: true`, and the same import id. No duplicate graph was created.

## Exercised rollback and roll-forward

The previous valid import remained intact as
`f844733d-bfc2-4809-a3c6-8cc8fbb5a84d` (49 nodes, 58 edges, content hash
`9d08056060753445727cff8cff7a7be1525b113dabcf45c4039bce98a1f5e912`).

1. Activating that import changed the live summary to 49 nodes / 58 edges and
   reported the 131/117 import as the previous import.
2. Activating `47e5358e-d04b-4969-99a2-ca88423ad054` restored 131 nodes / 117
   edges and reported the old import as previous.
3. The full fin-hub cutover gate was rerun after roll-forward and again returned
   `ready: true` with zero failures.

Activation changes only the per-source latest marker; both graph imports remain
immutable and readable.

## Caller and owner-surface review

A fresh code scan of repo-manager, fin-hub, hub-core, activity-core, ops-hub,
railiance-fabric, and the retirement project found no runtime callers of the
State Hub `/fabric/graph*` routes. Matches were contracts, operator docs, and
retirement inventory only.

Railiance Fabric currently documents a workstation-local registry service at
`127.0.0.1:8765`; no Kubernetes/Helm production deployment was found in
railiance-apps, railiance-cluster, rail-kubernetes, or railiance-fabric. Its
accepted snapshot set is deterministic, but many component snapshots predate
this cutover. `RAIL-FAB-WP-0028` owns the hosted runtime, persistence,
authentication, freshness, recovery, and eventual direct-consumer switch.