Money-safety idempotency fixes (external review bugs 1-3):
- processChargeGroup: aggregated refund key now hashes the sorted pending-row
set (chargeID-square-agg-<sha256 suffix>) so a changed group can never mark
a new row completed against an old smaller refund; >45-char chargeIDs use a
hashed prefix instead of verbatim truncation (which would collide charges on
Square's global key dedup). Same-set crash-retry keeps Square's dedup.
- CreateTerminalPayment saved_card: two-tier idempotency key — client-supplied
per-attempt UUID preferred (distinct identical charges no longer collapse),
deterministic booking+type+amount+card fallback for no-key retry safety.
PaymentModal sends a per-charge UUID cleared after success.
- ensureRefundKey: legacy NULL-key manual refunds persist a generated key to
the row BEFORE the Square call (race-safe AND idempotency_key IS NULL guard),
so a lost-response retry reuses the key and never double-refunds. Wired into
resumeManualPendingRefund and the sweep's manual-retry loop.
Classification + money-safety hardening:
- till.go/sweep.go: structured square.ErrorCode/IsNotFound are authoritative
when present; message-substring matching only for non-structured errors
(dev mock, client-side status errors). Fixes fragile string-matching driving
sweep retries and gift-card clawbacks.
- SaveCardForUser: ON CONFLICT (user_id, square_card_id) DO NOTHING + re-select
(was a latent UNIQUE-violation 500 on save-card retry).
- CreateBookingPayment: partial payments re-validated against remaining balance
inside the advisory lock (closes concurrent-overpayment race).
- InvalidateSquareCustomerCache on GDPR erasure paths (account.go,
time-blockers.go stale-guest anonymization).
- GetUserGiftCardBalanceAdmin: in-handler admin check (defense-in-depth).
- getCheckoutHTTP: warn on multi-payment checkouts instead of dropping
payments[1:].
- Cash/giftcard terminal branch: removed dead idempotency SELECT, "tip-" ->
"till-" prefix.
- UserPaymentModal: removed vestigial polling state; proper interval cleanup.
- account/+page.svelte: gift-card redeem dialog links /terms.
- nginx CSP: allow *.squarecdn.com and js.squareup.com so the Square Web
Payments SDK + card iframe can tokenize behind the proxy.
Tests: +8 regression tests covering changed-set refund keys, legacy NULL-key
single-refund, saved-card client-key dedup/no-dedup, concurrent partials, and
cache invalidation. Full suite + race detector clean via run-tests.sh lockfile.
Re-review (2 Oracle + security + QA + librarian + context-miner) surfaced fixes, all applied: (1) UserPaymentModal and the account-page gift-card buy now key the cached idempotency key on a stable 'new-card' sentinel instead of the cnon: nonce, so clearing the nonce on a failed charge no longer regenerates the key — a lost-response retry now dedups at Square instead of double-charging (the tip flows already keyed on amount only). (2) The create-with-redeem clawback now logs CRITICAL when the guarded balance reversal is blocked (previously silent), and its transaction DELETE is scoped to this sale instead of deleting every transaction on the card. (3) reconcileStalePaymentAtSquare now treats APPROVED/PENDING as non-terminal (leave pending) instead of definitively failed, matching Square's documented state machine. (4) GetTillCheckoutStatus returns 404 for a sale already swept to failed instead of reporting a live state. (5) The critical-payment scan job skips candidates whose booking was hard-deleted, so one orphan can no longer silence all critical alerts.
HIGH-1: a till sale whose card-machine checkout is provably dead, or whose Square reconcile proves the charge never landed, now claws back the funded gift card atomically with the failed mark (claim-first gating UPDATE serializes against the admin retry; blind-fail and ambiguous/lost-response rows never claw back, and a bare CANCEL_REQUESTED is not treated as proof of non-completion). HIGH-2: a card-machine checkout created at Square but not committed is cancelled on any pre-commit failure. HIGH-3: a cash/on_the_house retry of a pending card sale is reconciled at Square first (COMPLETED rescues + refuses cash; NOT_FOUND/FAILED/CANCELED allows cash; lost-response forces the card-method retry; ambiguous rejects). GetTillCheckoutStatus no longer resurrects a swept-failed sale, and the cash-completion UPDATE checks RowsAffected so the admin is never told to take cash against an already-resolved sale. 23 new tests covering the clawback matrix, the reconcile-or-reject matrix, cancel-on-error, and a till concurrency test.
Downgrades routine sweep bookkeeping from CRITICAL to WARN (genuine post-charge manual-reconciliation branches keep CRITICAL) and replaces the per-attempt time.After in tryAdvisoryLock with a single reusable timer.
One-off new-card charges now pass the cnon: nonce directly as source_id (no card-on-file, no customer). Save-card charges forward customer_id; legacy saved cards lazily provision a Square customer before charging (EnsureSquareCustomerForSavedCard). Terminal checkouts insert the terminal_checkouts row FIRST with a provisional tmp- id, then update with the real checkout_id, closing the crash window. GetDiscountPreviewHandler gains the fail-closed ownership check (IDOR). DeletePaymentMethod disables the card at Square before soft-delete. Sweep resolves provisional/tmp- terminal rows without a Square round-trip. GetCheckoutStatus rejects tmp- ids.
R1/R4: saved_card branch in CreateTerminalPayment now mirrors CreateTipPayment
- advisory lock (crussell:payment:<bookingID>) serializes concurrent double-clicks
- deterministic key bookingID-sc-type-amount-cardID (<=45 chars) so a lost-response
retry derives the same key and dedups instead of double-charging
- idempotency switch inside the lock: completed -> dedup, pending -> reuse with
pence amount-guard, failed -> clean 409
- success response includes card_brand/card_last4 (frontend already reads them)
R2: add 'failed' case to all four retry switches (tip, booking, gift card, till)
- a swept/definitively-rejected record returns 409 instead of 500-ing on the
idempotency_key UNIQUE constraint
R3: extend SweepStalePendingPayments to till_sales card rows
- sweeps pending till_sales (online_square/in_person_card) past Square's ~24h
key retention, closing the double-charge window for till sales
- swept rows logged with the same CRITICAL manual-reconciliation marker as the
refund sweep
Webhook fail-closed: reject 503 when SQUARE_WEBHOOK_SIGNATURE_KEY unset, 403 on
bad signature (was: skip verification in dev)
Refund status resolution: refunds now resolve by Square status
(COMPLETED/PENDING/FAILED/REJECTED) instead of assuming completed; real error
codes (REFUND_AMOUNT_INVALID, PAYMENT_NOT_REFUNDABLE, REFUND_ALREADY_PENDING)
added to the definitive/processed classification
HTTP client: CreateCard key truncated to <=45 chars, device_options always sent
(env SQUARE_TERMINAL_DEVICE_ID fallback), processing_fee reads amount_money,
ListCards cursor loop, refund keys hashed to <=45 chars
Other fixes: payment/till/gift-card advisory-lock + FOR UPDATE asymmetries,
GetPaymentByID NULL scans, loyalty redemption lock, card upsert on conflict,
mock ccof: prefix parity, IsValidSquareCheckoutID for real Square IDs,
isAdminRequest defense-in-depth on all 6 admin payment handlers, webhook
signature docs, M8/L5 debug markers removed
Docs: README/FC/TM/Overview updated (22 jobs, 20 CRITICAL sites, 23-section
GDPR export, sweep jobs, webhook fail-closed); P11 plan marks remaining items
(sandbox smoke test, M-8 customer_id, saved-card key dedup trade-off) as
deferred with rationale; gap backlog pruned of completed items
popertots