N1 (HIGH) — BuyGiftCard concurrent same-key retry could double-issue gift
cards (2× value for 1 charge). Added pg_advisory_lock on the idempotency key
(mirroring the tip pattern) acquired before the idempotency check, so
concurrent same-key retries serialize and only one executes gift-card
creation.
N2 — Amount-equality guards in both reuse branches (CreateTipPayment and
BuyGiftCard). A same-key retry with a different amount now returns 400
instead of silently mutating the pending record's books/VAT/refund caps.
N3 — test coverage:
- TestBuyGiftCard_RetryPending_ReattemptsCharge: pending record + same-key
retry re-attempts, reuses the record (count=1), completes, and issues the
gift card exactly once.
- TestCreateCheckoutHTTP_DeviceOptionsWireShape: httptest.Server asserts
device_id is under checkout.device_options (not top-level). Extracted
createCheckoutHTTPWithClient for injectable base URL.
- MockClient.CreatePayment now dedups on idempotency key (paymentByKey map),
matching real Square behaviour.
N4 — Corrected the savepoint comments in handlers.go and giftcards.go: the
savepoint only exists in the test harness; in production db.Conn.Begin is a
plain tx and the status UPDATE runs on a separate pooled connection. Commit
is a harmless no-op in prod but required in tests.
Bonus bug fixed: CheckIdempotencyByKey scanned NULL booking_id/gift_card_id
(gift-card purchases) into plain string, failing with 'cannot scan NULL'.
Now uses sql.NullString.
Docs: Technical Manual.md:53 and Feature Catalog.md (2.1, 2.5) corrected —
no longer claim Web Payments SDK is live; new-card entry is documented as
pending P11, saved-card flow works via ccof tokens, dev mock rejects raw PANs.
New test files cover previously untested paths across DAV, validators,
S3, Square, mw, bookings, user, and payments packages.
Includes mock fix: HoldCheckouts flag on MockClient allows tests to
pause auto-complete goroutine for testing PENDING checkout states.
Coverage: 50.4% → 65.0% (+14.6pp)
Refactor BuyGiftCard to insert pending payment before Square call with VAT applied. Add transaction wrapping to gift card handlers. Remove redundant Content-Type header sets. Migrate all time.Now() to clock.Now().
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Migrate all test files from SetupTestDB/db.DB pattern to per-test transactions:
- Replace SetupTestDB(t) with SetupTestTx(t) for context + transaction
- Replace db.DB.Query/QueryRow/Exec with tx.Query/QueryRow/Exec
- Replace context.Background() with context from SetupTestTx
- Replace defer rows.Close() pattern with explicit rows.Close()
- Add testdb.SeedBaseline(pool) to all TestMain functions
- Wire db.Conn = db.NewPoolProxy(pool) in all TestMain functions
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
- Added generic formatAndPreserveCursor() helper on frontend to track
and restore selection caret position during dynamic input sanitization
- Applied to all card inputs, gift card code inputs, and expiry inputs
- Added Luhn validation (isValidLuhn) for saved cards and gift cards
- Rebuilt payments test DB and got 100% green tests