Don't hold the `NetworkGraph` read lock across an await point

Holding the `NetworkGraph` read lock across a query await point
can cause a deadlock if another task tries to handle a gossip
message at the same time.

diff --git a/src/lookup.rs b/src/lookup.rs
index 04e46bd0d8ec9f1292445605085e659c5dc3c95b..263514d81bbd9ba13df32ff47822caaef73adfef 100644 (file)
--- a/src/lookup.rs
+++ b/src/lookup.rs
@@ -160,7 +160,6 @@ pub(super) async fn fetch_channel_announcements(delta_set: &mut DeltaSet, networ
                // — Obtain all updates, distinct by (scid, direction), ordered by seen DESC
                // — From those updates, select distinct by (scid), ordered by seen ASC (to obtain the older one per direction)
                let reminder_threshold_timestamp = SystemTime::now().checked_sub(config::CHANNEL_REMINDER_AGE).unwrap();
-               let read_only_graph = network_graph.read_only();
 
                let params: [&(dyn tokio_postgres::types::ToSql + Sync); 2] =
                        [&channel_ids, &reminder_threshold_timestamp];
@@ -189,7 +188,7 @@ pub(super) async fn fetch_channel_announcements(delta_set: &mut DeltaSet, networ
                        // way might be able to get away with not using this
                        (*current_channel_delta).requires_reminder = true;
 
-                       if let Some(current_channel_info) = read_only_graph.channel(scid as u64) {
+                       if let Some(current_channel_info) = network_graph.read_only().channel(scid as u64) {
                                if current_channel_info.one_to_two.is_none() || current_channel_info.two_to_one.is_none() {
                                        // we don't send reminders if we don't have bidirectional update data
                                        continue;