merchant

commit 2fe548c732fbe0cd46c1142b94f9597527a3a28f
parent 7dbf4d319487cc38e65eea1c8dc9c21d4dec47f6
Author: Christian Grothoff <grothoff@gnunet.org>
Date:   Fri, 14 Aug 2026 23:31:22 +0200

subtract tip from total to be paid to compute the regular contract total

Diffstat:
M
src/backend/taler-merchant-httpd_post-templates-TEMPLATE_ID.c
 | 
34
++++++++++++++++++++++++++++++++++

1 file changed, 34 insertions(+), 0 deletions(-)
diff --git a/src/backend/taler-merchant-httpd_post-templates-TEMPLATE_ID.c b/src/backend/taler-merchant-httpd_post-templates-TEMPLATE_ID.c
@@ -1730,6 +1730,40 @@ handle_phase_compute_price (struct UseContext *uc)
       GNUNET_assert (uc->template_contract.no_amount);
       *uc->compute_price.totals
         = uc->parse_request.amount;
+      if (! uc->parse_request.no_tip)
+      {
+        /* Per the API specification, the client's 'amount' is "the
+           amount to be paid, including tip", while the total we compute
+           in this phase excludes the tip: #handle_phase_check_tip()
+           adds it back on top.  Without removing it here, the total
+           would end up being 'amount' + 'tip' and could thus never
+           match the 'amount' that #handle_phase_check_total() compares
+           it against. */
+        if (GNUNET_YES !=
+            TALER_amount_cmp_currency (&uc->parse_request.tip,
+                                       uc->compute_price.totals))
+        {
+          GNUNET_break_op (0);
+          use_reply_with_error (uc,
+                                MHD_HTTP_CONFLICT,
+                                TALER_EC_MERCHANT_GENERIC_CURRENCY_MISMATCH,
+                                uc->parse_request.tip.currency);
+          return;
+        }
+        if (0 >
+            TALER_amount_subtract (uc->compute_price.totals,
+                                   uc->compute_price.totals,
+                                   &uc->parse_request.tip))
+        {
+          GNUNET_break_op (0);
+          use_reply_with_error (
+            uc,
+            MHD_HTTP_CONFLICT,
+            TALER_EC_MERCHANT_POST_USING_TEMPLATES_AMOUNT_CONFLICT_TEMPLATES_CONTRACT_AMOUNT,
+            "tip exceeds amount");
+          return;
+        }
+      }
       /* Only an amount the client chose is subject to the limits. */
       if (GNUNET_OK !=
           check_amount_limits (uc,