From 710812f5a8a7985441a04bfbaaeb346bf1551cd4 Mon Sep 17 00:00:00 2001
From: teor <teor@riseup.net>
Date: Wed, 26 Apr 2023 06:05:37 +1000
Subject: [PATCH] Avoid a rare panic when a connection is dropped

---
 zebra-network/src/peer/client.rs | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/zebra-network/src/peer/client.rs b/zebra-network/src/peer/client.rs
index 68e694618f8..3b6e0fcdc78 100644
--- a/zebra-network/src/peer/client.rs
+++ b/zebra-network/src/peer/client.rs
@@ -621,8 +621,13 @@ impl Service<Request> for Client {
             Ok(()) => {
                 // The receiver end of the oneshot is itself a future.
                 rx.map(|oneshot_recv_result| {
-                    oneshot_recv_result
-                        .expect("ClientRequest oneshot sender must not be dropped before send")
+                    // The ClientRequest oneshot sender should not be dropped before sending a
+                    // response. But sometimes that happens during process or connection shutdown.
+                    // So we just return a generic error here.
+                    match oneshot_recv_result {
+                        Ok(result) => result,
+                        Err(oneshot::Canceled) => Err(PeerError::ConnectionDropped.into()),
+                    }
                 })
                 .boxed()
             }