# Inventory Module — Manual Review Checklist

## Concurrency Safety
- [ ] Stock deduction uses atomic operations (optimistic lock, Redis decr, DB atomic update)
- [ ] No SELECT + UPDATE gap for stock operations
- [ ] Lock granularity: per-SKU, not global lock on inventory table

## Pre-sale / Reservation
- [ ] Pre-sale inventory separated from actual inventory
- [ ] Reservation timeout and auto-release mechanism
- [ ] Reservation-to-actual-deduction transition is atomic

## Audit Trail
- [ ] Every stock change logged with: SKU, quantity, operation type, order ID, timestamp
- [ ] Stock reconciliation queryable from audit log
- [ ] No direct DB updates bypassing the service layer

## Stock Recovery
- [ ] Order cancellation triggers stock recovery
- [ ] Recovery is idempotent (double-cancel doesn't double-recover)
- [ ] Recovery handles edge case: stock recovered after SKU deleted