From f261afc7393e14eb65e1a959e9cdbd51eb612973 Mon Sep 17 00:00:00 2001
From: Michal Kuratczyk <michal.kuratczyk@broadcom.com>
Date: Mon, 24 Nov 2025 14:02:52 +0100
Subject: [PATCH] Set settle modes in link error frames

Follow-up to https://github.com/rabbitmq/rabbitmq-server/pull/14389

Without these changes, the attach frame doesn't set
any settlement mode. This leads to settlement negotiation
errors hiding the actual error.

For example,
omq amqp -y 0 -t /queues/no-such-queue
omq amqp -x 0 -T /queues/no-such-queue

Returned `amqp: sender settlement mode "unsettled" requested, received "mixed" from server"`,
when the actual error in the next (detach) frame was `amqp:not-found`.
However, the attach frame triggers a client-side error before the
detach frame is processed.
---
 deps/rabbit/src/rabbit_amqp_session.erl | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/deps/rabbit/src/rabbit_amqp_session.erl b/deps/rabbit/src/rabbit_amqp_session.erl
index b8e6ce82f5d..d9d9611ea0d 100644
--- a/deps/rabbit/src/rabbit_amqp_session.erl
+++ b/deps/rabbit/src/rabbit_amqp_session.erl
@@ -1136,7 +1136,9 @@ handle_frame(#'v1_0.attach'{name = {utf8, NameBin} = Name,
                             handle = Handle,
                             role = Role,
                             source = Source,
-                            target = Target} = Attach,
+                            target = Target,
+                            snd_settle_mode = SndSettleMode,
+                            rcv_settle_mode = RcvSettleMode} = Attach,
              State) ->
     try
         ok = validate_attach(Attach),
@@ -1152,7 +1154,9 @@ handle_frame(#'v1_0.attach'{name = {utf8, NameBin} = Name,
                                      handle = Handle,
                                      role = ?AMQP_ROLE_RECEIVER,
                                      source = Source,
-                                     target = null};
+                                     target = null,
+                                     snd_settle_mode = SndSettleMode,
+                                     rcv_settle_mode = RcvSettleMode};
                               ?AMQP_ROLE_RECEIVER ->
                                   #'v1_0.attach'{
                                      name = Name,
@@ -1160,7 +1164,9 @@ handle_frame(#'v1_0.attach'{name = {utf8, NameBin} = Name,
                                      role = ?AMQP_ROLE_SENDER,
                                      source = null,
                                      target = Target,
-                                     initial_delivery_count = ?UINT(?INITIAL_DELIVERY_COUNT)}
+                                     initial_delivery_count = ?UINT(?INITIAL_DELIVERY_COUNT),
+                                     snd_settle_mode = SndSettleMode,
+                                     rcv_settle_mode = RcvSettleMode}
                           end,
             Detach = #'v1_0.detach'{handle = Handle,
                                     closed = true,