Files
ERP/docs/PILOT_READINESS.md
T
denis_ireri ee5bb5beb8 Stop simultaneous transfers from overdrawing a branch
A transfer read the sending branch's stock and then wrote its movements
as two separate steps. Requests arriving together all saw the same
balance and all passed the check: five simultaneous transfers of 4 from
a stock of 10 all succeeded, sending 20.

The check and the write now run under withStockLock: a short lease on
one product's stock at one branch, taken with a single atomic upsert
(it only succeeds when no unexpired lease exists) and released when the
request finishes. A second request waits briefly, then sees the updated
balance; after 5 seconds it gets 409 "try again". A lease expires after
10 seconds, so a crashed request cannot block the stock for good.

Physical counts take the same lock, so a count is never computed from a
balance a transfer is changing. A double-tapped transfer that races
itself still moves stock once. Sales do not take the lock: they are
recorded even when stock runs out, by design.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-12 10:57:17 +03:00

9.2 KiB

Pilot readiness changes

This branch (fix/pilot-readiness) closes the gaps found when the MVP was reviewed against PRD.md and REVIEW.md. This page records what changed, the decisions taken along the way, and what is still open.

What changed

Tenant isolation and roles (PRD 5.1)

  • Every role-limited API route goes through authorize() in src/lib/server/auth.ts: 401 when signed out, 403 for the wrong role. Cashiers can no longer read profit, expenses or purchases, or record expenses and purchases. Only the owner creates or edits products and prices.
  • PATCH /api/users/:id deactivates and reactivates staff (managers: only their own cashiers). Deactivating or moving a user revokes their device sessions.
  • PATCH /api/branches/:id renames a branch (owner only).
  • Login and token refresh refuse an inactive or SUSPENDED business.
  • Public signup refuses any address in PLATFORM_ADMIN_EMAILS.
  • Ids in query strings and bodies are validated (400, not a 500), inventory routes check the product belongs to the tenant, and reconciliation lookups are tenant-scoped.

Stock ledger and transfers (PRD 5.2)

  • StockMovement is the ledger: a branch's stock of a product is the sum of its movements. Each movement names its cause, and (type, refId) is unique, so a replayed sale or retried transfer never moves stock twice.
  • Sales and confirmed M-Pesa payments deduct stock; purchases of a catalogue product add it.
  • POST /api/stock/transfers moves stock between branches. POST /api/stock/adjustments records opening stock, breakage and physical counts. GET /api/stock returns stock per branch with LOW/OUT flags (per-product lowStockThreshold, default 10).
  • The admin Stock page (/admin/stock) covers all of this, plus the existing morning dispatch and evening count. The dashboard shows stock on hand per branch.

Offline POS and sync (PRD 5.3, 5.5)

  • POST /api/transactions/cash answers each sale with saved, duplicate or rejected. Previously a replayed sale was skipped silently, the device never marked it synced, and once more than 100 rows piled up every sync failed.
  • The device queue (src/lib/offlineQueue.ts) is keyed by cashier and branch, sends only the signed-in cashier's sales, chunks to 50 per request, and stops retrying rejected sales (they are shown to the cashier instead).
  • A service worker (public/sw.js) caches the app shell, and the last session and product list are kept on the phone, so the terminal opens and sells with no network.
  • Sales can contain several products, the customer phone is optional for cash, and the terminal shows a printable receipt.

Other

  • "Today" and "this month" follow Africa/Nairobi, not the server's UTC clock (src/lib/server/businessDay.ts).
  • M-Pesa is behind FEATURE_MPESA (off by default; out of scope for the pilot per PRD section 4).

Decisions taken

Decision Why
Offline sales are always accepted, even if they take stock below zero. The sale already happened. Refusing it would lose real cash. Negative stock is shown on the Stock page and fixed with a physical count.
Transfers are refused when the sending branch lacks the stock. Transfers are made online by a manager, so they can be checked. The check and the move run under a short per-branch, per-product lock (withStockLock in src/lib/server/stock.ts), so simultaneous transfers cannot together overdraw a branch; physical counts take the same lock.
The server price is authoritative; a different price shown on the device is kept (clientUnitPrice) and flagged (priceMismatch). Trusting the device's price would let a cashier under-charge. Overwriting it silently would hide a cash discrepancy.
A queued sale stays with the branch where it was recorded, even if the cashier has since moved. That is where the stock left and the cash was taken.
A product deactivated while a phone was offline is still recorded at its price. Same reason as the first row: the sale happened.

Rolling out to an existing database

  • No migration is needed: new fields have defaults, and Mongoose creates the new indexes on start-up.
  • Existing branches start with no stock on record. Before the pilot, each branch should record an opening count on the Stock page.
  • Cashiers' phones upgrade their offline queue automatically; any unsynced sales from the old version are sent on the next sync.

Testing

  • npm test runs 62 API tests against an in-memory MongoDB, covering role enforcement, tenant isolation for sales, stock and transfers, suspension, the sync protocol (including a 120-sale backlog replayed twice), and the business day.
  • The offline flow was also checked end to end in headless Chrome: sign in, stop the server, reload the terminal, record two sales, restart the server, confirm they sync once and deduct stock.

Follow-ups from the 11 October 2026 test report

The initial test report (run on the build before these changes) raised seven findings and a retest plan. All of them are addressed on fix/test-report-followups:

Finding What changed
F-01 Trial allows one branch A business on its free trial may run 2 active branches whatever its tier (TRIAL_MAX_BRANCHES in src/lib/tiers.ts). After the trial the tier's limit applies to adding branches.
F-02 No current stock Done in the previous change (stock ledger). Purchases recorded before the ledger existed are added by npm run backfill:stock.
F-03 Reversed report dates Refused in the page and by the API (400). The page labels which period the cards show. Report dates are Nairobi business days.
F-04 No way back for deactivated products Products page lists deactivated products under a toggle, with Reactivate. Deactivating warns about stock still on hand; that stock stays on the Stock page and can be transferred or counted out.
F-05 Eggs shown as litres Products carry a unit (L, ml, kg, g, pcs, tray, pack), chosen when the product is created and shown everywhere.
F-06 No branch or staff removal Staff: deactivate/reactivate (previous change). Branches: rename and deactivate/reactivate on the Branches page. A branch can only be deactivated once it has no stock and no active staff; its history stays in reports.
F-07 Purchases shown as cost of goods Cost of goods sold is now units sold x the product's average buying price. Purchases in the period are shown separately as "Stock purchased", with a "Cash surplus" line.
STA-04 No invites Staff and new branch managers can be invited: the owner or manager gets a one-time link (7 days) to send, and the person sets their own password. A new link can be made from Staff.
CAT-12 Zero price, duplicates Prices must be above zero; product names are unique per business, ignoring case.
OFF-02 Local stock deduction The till shows each product's stock and deducts every sale immediately, online or offline.
POS-02 / INV-05 Oversell, cancel The till warns before selling more than the recorded stock and asks to confirm (it does not block, because the sale may already have happened). A "Clear sale" button empties the cart.

tests/retest-plan.test.ts runs the report's completion and retest plan (online sale, transfer, two offline sales replayed twice, a Branch B sale) and checks every balance and total it predicts.

Before re-running the test report's plan on ZERRO

  1. Deploy, then run npm run backfill:stock once so the existing test purchases count as stock. Run it before anyone records an opening count, or those units would be counted twice.
  2. ZERRO is trialling, so it can now add Branch B without a plan change.
  3. Create the manager and cashier logins with invite links from Staff.

Branch prices

Owners set a different price per branch on Products -> Branch prices (/admin/prices, API /api/branch-prices). Setting a price back to the default removes the override. Branch managers see their own branch's prices read-only.

  • It is a Growth/Enterprise feature (as the plan list already advertised), also available during the free trial. After a trial on Starter, existing branch prices keep applying and can be reset, but not changed.
  • The till, cash sales and M-Pesa all read the branch price. A phone picks up a change the next time it loads products; a sale it records offline in the meantime is kept at the server's price and flagged as a price mismatch.
  • The Products page always shows default prices.

Still open

  • Global email and phone uniqueness. One person cannot work for two businesses, and signup reveals whether an address is already registered.
  • Isolation by convention. Tenant filters are still written per route. The tests cover the sales, stock, transfer and access paths, not every route.
  • Cost of goods is an average. It uses each product's average buying price across the business, not first-in-first-out per branch. Units sold with no purchase on record are counted and flagged, but have no cost.
  • M-Pesa, if turned on. Only one product per payment. A prompt that times out still needs a manual check before taking cash.
  • Not modelled yet: email verification at signup, sending invites by email (links are shared by hand, e.g. WhatsApp), empty-bottle and deposit tracking, home-screen icons for the PWA.