merchant

commit 7247592dd7ce3542a26a72897c9b6e6021f0241a
parent 8aca4ab356fa801c8c5d6ec944388f5623679ee1
Author: Christian Grothoff <christian@grothoff.org>
Date:   Fri,  9 Oct 2026 22:39:00 +0200

Fixes that paying the same order twice with the same coin
and different amounts (smaller the 2nd time) the merchant
backend would incorrectly trigger a refund.

Diffstat:
M
src/backend/taler-merchant-httpd_post-orders-ORDER_ID-pay.c
 | 
21
++++++++++++++++-----

1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/src/backend/taler-merchant-httpd_post-orders-ORDER_ID-pay.c b/src/backend/taler-merchant-httpd_post-orders-ORDER_ID-pay.c
@@ -290,6 +290,15 @@ struct DepositConfirmation
   bool matched_in_db;
 
   /**
+   * true if #deposit_paid_check() found a deposit of this coin for
+   * this order in the database, regardless of the exchange URL and
+   * amount given by the client.  Such a coin must never be offered
+   * a refund in the "already paid" response, as the refund would
+   * be honored by the exchange against the existing deposit.
+   */
+  bool deposited_in_db;
+
+  /**
    * True if this coin is in the current batch.
    */
   bool in_batch;
@@ -4397,10 +4406,12 @@ deposit_paid_check (
   {
     struct DepositConfirmation *dci = &pc->parse_pay.dc[i];
 
+    if (0 !=
+        GNUNET_memcmp (&dci->cdd.coin_pub,
+                       coin_pub))
+      continue;
+    dci->deposited_in_db = true;
     if ( (0 ==
-          GNUNET_memcmp (&dci->cdd.coin_pub,
-                         coin_pub)) &&
-         (0 ==
           strcmp (dci->exchange_url,
                   exchange_url)) &&
          (GNUNET_YES ==
@@ -4678,8 +4689,8 @@ phase_contract_paid (struct PayContext *pc)
     struct DepositConfirmation *dci = &pc->parse_pay.dc[i];
     struct TALER_MerchantSignatureP merchant_sig;
 
-    if (dci->matched_in_db)
-      continue;
+    if (dci->deposited_in_db)
+      continue; /* part of the payment on file, never refund it here */
     TALER_merchant_refund_sign (&dci->cdd.coin_pub,
                                 &pc->check_contract.h_contract_terms,
                                 0, /* rtransaction id */