From 0e368dab0943067c060ad45578a4c4cbdc3434a6 Mon Sep 17 00:00:00 2001
From: Adam Soltys <adam@coinos.io>
Date: Sun, 17 May 2026 23:22:51 -0700
Subject: mirror payment records to arc + atomic /confirm lock to prevent
 double-credits
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Follows up the Apr 29 double-credit incident. Two parallel callers of
/confirm (walletnotify, catchUp, bulk sweeps) could each read
p.confirmed=false and each run the multi() that increments balance —
because main-db pointers were sometimes missing while arc still had them,
gf()'s arc fallback returned stale state. Three pieces here:

- routes/payments.ts: SET NX EX 60 lock around the /confirm credit block
  keyed by `confirmlock:${txid}:${vout}`. Concurrent callers short-circuit
  cleanly. The lock is released on success and on every early-return.

- lib/payments.ts credit() + routes/payments.ts /confirm: mirror the
  payment/invoice records and the `payment:<txid>:<vout>` / `payment:<hash>`
  pointer keys into arc as soon as they're written. gf() will then find
  the prior credit via arc fallback even if the main-db copy is wiped by
  a future data-loss event.

- routes/payments.ts hide `revertedDuplicate` payments from the user's
  payment list — matches the same filter added to lib/nwc.ts list_transactions
  so reverted records never surface in either rendering path.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 lib/payments.ts | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

(limited to 'lib')

diff --git a/lib/payments.ts b/lib/payments.ts
index 9d658294..5d2bf0e6 100644
--- a/lib/payments.ts
+++ b/lib/payments.ts
@@ -1,6 +1,6 @@
 import config from "$config";
 import api from "$lib/api";
-import { db, g, ga, gf, s } from "$lib/db";
+import { archive, db, g, ga, gf, s, sa } from "$lib/db";
 import { generate } from "$lib/invoices";
 import ln from "$lib/ln";
 import { err, l, warn } from "$lib/logging";
@@ -298,8 +298,13 @@ export const credit = async ({
     p.confirmed = false;
     balanceKey = "pending";
     await s(`payment:${txid}:${vout}`, id);
+    // Mirror the txid:vout pointer into arc so future bulk /confirm sweeps find
+    // the prior credit via gf() fallback and don't double-credit. See
+    // feedback_apr29_double_credit_incident.md for the incident this prevents.
+    await sa(`payment:${txid}:${vout}`, id);
   } else {
     await s(`payment:${hash}`, id);
+    await sa(`payment:${hash}`, id);
   }
 
   const m = await db.multi();
@@ -323,6 +328,10 @@ export const credit = async ({
     .set(`${aid || uid}:payments:last`, p.created)
     .exec();
 
+  // Mirror the payment record + invoice into arc for the same protection.
+  await sa(`payment:${p.id}`, p);
+  await sa(`invoice:${inv.id}`, inv);
+
   if (inv.items?.length) {
     formatReceipt(inv.items, inv.currency);
     p.items = inv.items;
-- 
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