# Modern runtime J4.2 — inventory transaction ownership

**Status:** COMPLETE
**Production commit:** `011efbeaa72509b35ea7f4a442e50a2377ae1ea4`
**Parent plan:** `../plans/2026-07-26-modern-runtime-slice-j4.md`

## Result

`RuntimeInventoryState` is the single presentation-independent owner for the
live external-container state, item-mana state, shortcut assignments, desired
spell-component counts, and the retail one-inventory-request-at-a-time
transaction gate.

It borrows J3's exact `ClientObjectTable`; it does not construct or synchronize
a second item collection. The live-session router, item interaction,
retained UI, developer tools, current-runtime/plugin boundary, and future
no-window hosts all observe those same owner instances.

`InventoryTransactionState` now owns the request/response gate previously
split across App interaction code. It records the retail request token,
matches the corresponding response, maintains the shared busy reference,
tracks use reservations, and resets the transaction atomically. Callback
failures are isolated after canonical state commits, so one observer cannot
strand the busy cursor or prevent a later request.

Presentation-only state remains in App: pending backpack-slot projection,
drag/drop hover and selection, cursor choice, item icons, panel layout, and
optimistic visual placement. App may borrow the Runtime transaction owner but
cannot dispose or replace it.

## Retail basis

The ownership move preserves the already-ported retail transaction behavior:

- `ACCWeenieObject::RecordRequest` at `0x0058C220`;
- `ACCWeenieObject::RecordResponse` at `0x0058CAB0`;
- `ClientUISystem::UsageCallback` at `0x00565B20`;
- `2026-07-23-retail-use-busy-ownership-pseudocode.md`;
- `2026-07-13-retail-give-item-pseudocode.md`.

ACE and Holtburger remain interpretation cross-checks as recorded in the
busy-ownership pseudocode. No request ordering, wire packet, optimistic move,
rollback, use-completion, or cursor behavior changed in J4.2.

## Automated evidence

- Runtime suite: 157 passed.
- App suite: 3,770 passed / 3 established skips.
- Core suite: 3,305 passed / 2 established skips.
- Complete Release solution: 8,515 passed / 5 established skips.
- Release build: pass, zero errors. A clean rebuild reports 17 established
  test warnings; the J4.2 diff introduces none.
- `git diff --check`: pass.

The focused matrix covers exact object-table identity, external-container
open/replace/close, item-mana replacement, shortcut/component replacement,
request/response matching, use reservations, dispatch failure rollback,
observer failure isolation, reset/reconnect, borrowed lifetime, idempotent
disposal, and two independent Runtime instances.

One parallel full-suite run hit the established allocation-sensitive portal
projection test with a 1,536-byte measurement. The isolated App rerun passed,
and an immediate complete-solution rerun passed all 8,515 tests without a code
change.

## Exact-binary connected evidence

`logs/connected-world-gate-20260726-082057/report.json` passed on exact source
and embedded binary commit
`011efbeaa72509b35ea7f4a442e50a2377ae1ea4`:

- six capped checkpoints through login, outdoor/dungeon/facility travel and
  revisit plus one fresh-process uncapped reconnect checkpoint;
- 244.011-second capped route and 61.422-second reconnect route;
- both sessions exited gracefully with code zero;
- zero failures.

Its only warning is the established set of 25 expected world-edge landblock
misses.

## Divergence audit

J4.2 changes lifetime ownership and failure containment only. It introduces no
new retail behavior and retires no registered divergence, so the divergence
register is unchanged.

## Rollback

```text
git revert 011efbeaa72509b35ea7f4a442e50a2377ae1ea4
```

Do not revert J3's canonical entity/object ownership to mask an inventory
transaction failure.

## Next boundary

J4.3 moves construction and lifetime of the coupled `Spellbook` and
`LocalPlayerState` into Runtime. Immutable DAT spell tables remain supplied by
the content host; retained spellbook, active-effect, character-sheet, and
paperdoll presentation remain in App/UI.