Follow-up to the comprehensive payment-system review. Fixes the issues the
review found in the initial integration, plus the rough edges it introduced.
Money-safety:
- Replay-by-key now replays the FULL original request verbatim from a stored
square_request_snapshot, so a retained idempotency key returns the original
payment instead of IDEMPOTENCY_KEY_REUSED (previously the row sat pending
forever). IDEMPOTENCY_KEY_REUSED remains ambiguous (never proof of no charge).
- Dev mock mirrors real Square for unknown-key replays: ccof: saved-card
sources are charged and rescued; spent cnon: nonces surface
ErrReplayKeyNotRetained. (Fixes dev/prod parity divergence.)
- Webhook dedup row committed AFTER dispatch (at-least-once); FAILED till sales
claw back gift-card funding; event-type strings match Square's real catalog.
- Expired-gift-card cancellation refunds set creditFailed (never a phantom
'completed' refund); cancellation refunds lock all payment rows ascending.
- Sweep never rescue-completes a gift-card purchase without delivering the card.
- Tip no-client-key fallback is a deterministic count-based key under the
booking advisory lock (retry-safe, distinct tips don't collapse).
- M-cap subtracts completed refunds, clamped to [0, total].
2FA (PSD2 SCA stand-in) for online saved-card payments:
- Full feature: status/setup/verify/disable endpoints, gating helper wired into
all 7 saved-card charge paths (incl. BuyGiftCard + admin saved-card), account
admin-tab settings UI, frontend gating across all payment surfaces.
- Enforcement is FAIL-CLOSED: on unless REQUIRE_2FA=false or an explicit
mock/dev SQUARE_ENVIRONMENT; startup warning when off in a non-dev env.
- Verify is brute-force hardened (5-attempt lockout, timing-safe compare);
plaintext codes only logged when enforcement is off (dev).
- GDPR: anonymize_user also scrubs 2FA columns and staff notes.
Infra/docs:
- nginx: /api/ response cache removed (cross-user disclosure); port 80
redirects to HTTPS (localhost/RFC1918 exempt, end-anchored regexes); HSTS;
separate webhook rate-limit zone.
- Schema: users 2FA columns; payments/till_sales square_source_id +
square_request_snapshot.
- Legal docs: gift-card cooling-off, international-transfers section, tips
policy; Gap Backlog P3 webhooks marked done; stale counts/wording corrected.
- Flaky test race fixed (t.Parallel + global mock mutation); suite 26/26
packages green, 2,142 tests, svelte-check clean.
The in-memory dedup is now only a fast path; the square_webhook_events INSERT ... ON CONFLICT DO NOTHING is the source of truth, so replays across restarts and after FIFO eviction are skipped. A DB failure fails closed with 503 so Square retries. Empty event_ids are rejected with 400 (no dispatch, no dedup row). Ordering trade-off (insert-before-dispatch) documented for when handlers mutate state.
payment.updated/refund.updated handlers log only the Square object id and payload length instead of the raw JSON body (which contained buyer email, card brand/last4, cardholder name). Add a test asserting no raw payload reaches the log.
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
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>
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