Fix timeout refund on an unlimited channel

.changelog/unreleased/bug-fixes/4822-fix-timeout-unlimited.md

@@ -0,0 +1,2 @@
+- Fix refund when timeout on unlimited channel
+  ([\#4822](https://github.com/namada-net/namada/issues/4822))

crates/ibc/src/vp/mod.rs

@@ -400,13 +400,18 @@ where
             IbcMessage::NftTransfer(msg_nft_transfer) => {
                 Some(&msg_nft_transfer.message.chan_id_on_a)
             }
-            IbcMessage::Envelope(boxed) => {
-                if let MsgEnvelope::Packet(PacketMsg::Recv(msg)) = &**boxed {
+            IbcMessage::Envelope(boxed) => match &**boxed {
+                MsgEnvelope::Packet(PacketMsg::Recv(msg)) => {
                     Some(&msg.packet.chan_id_on_b)
-                } else {
-                    None
                 }
-            }
+                MsgEnvelope::Packet(PacketMsg::Ack(msg)) => {
+                    Some(&msg.packet.chan_id_on_a)
+                }
+                MsgEnvelope::Packet(PacketMsg::Timeout(msg)) => {
+                    Some(&msg.packet.chan_id_on_a)
+                }
+                _ => None,
+            },
         };
         if let Some(channel) = transfer_channel {
             let unlimited_channel_key = unlimited_channel_key(channel);

crates/tests/src/e2e/ibc_tests.rs

@@ -1258,7 +1258,7 @@ fn ibc_unlimited_channel() -> Result<()> {
 
     // Start relaying
     let hermes = run_hermes(&hermes_dir)?;
-    let _bg_hermes = hermes.background();
+    let bg_hermes = hermes.background();
 
     let ibc_denom_on_namada =
         format!("{port_id_namada}/{channel_id_namada}/{COSMOS_COIN}");
@@ -1378,6 +1378,69 @@ fn ibc_unlimited_channel() -> Result<()> {
         1_000_000,
     )?;
 
+    // Transfer to an invalid address from Namada
+    transfer(
+        &test,
+        ALBERT,
+        "invalid_receiver",
+        &ibc_denom_on_namada,
+        1,
+        Some(ALBERT_KEY),
+        &port_id_namada,
+        &channel_id_namada,
+        None,
+        None,
+        None,
+        None,
+        false,
+    )?;
+    wait_for_packet_relay(
+        &hermes_dir,
+        &port_id_namada,
+        &channel_id_namada,
+        &test,
+    )?;
+
+    // Check if the token has been refunded by an ack with an error
+    check_balance(&test, ALBERT, &ibc_denom_on_namada, 1)?;
+
+    // Stop Hermes for timeout test
+    let mut hermes = bg_hermes.foreground();
+    hermes.interrupt()?;
+
+    // Timeout transfer from Namada
+    transfer(
+        &test,
+        ALBERT,
+        &gaia_receiver,
+        &ibc_denom_on_namada,
+        1,
+        Some(ALBERT_KEY),
+        &port_id_namada,
+        &channel_id_namada,
+        Some(Duration::new(10, 0)),
+        None,
+        None,
+        None,
+        false,
+    )?;
+    // wait for the timeout
+    sleep(10);
+
+    // Restart relaying
+    let hermes = run_hermes(&hermes_dir)?;
+    let _bg_hermes = hermes.background();
+
+    wait_for_packet_relay(
+        &hermes_dir,
+        &port_id_namada,
+        &channel_id_namada,
+        &test,
+    )?;
+
+    // Check if the token has been refunded
+    check_balance(&test, ALBERT, &ibc_denom_on_namada, 1)?;
+
     Ok(())
 }