fix: correctly handle disconnect from only peer

Author: SupernaviX

modules/peer_network_interface/src/chain_state.rs

@@ -192,6 +192,10 @@ impl ChainState {
         }
     }
 
+    pub fn clear_preferred_upstream(&mut self) {
+        self.preferred_upstream = None;
+    }
+
     pub fn next_unpublished_block(&self) -> Option<(&Header, &[u8], bool)> {
         let (slot, hash) = self.unpublished_blocks.front()?;
         let slot_blocks = self.blocks.get(slot)?;

modules/peer_network_interface/src/network.rs

@@ -177,11 +177,13 @@ impl NetworkManager {
         };
         warn!("disconnected from {}", peer.conn.address);
         let was_preferred = self.chain.preferred_upstream.is_some_and(|i| i == id);
-        if was_preferred && let Some(new_preferred) = self.peers.keys().next().copied() {
-            self.set_preferred_upstream(new_preferred);
-        }
-        if self.peers.is_empty() {
-            warn!("no upstream peers!");
+        if was_preferred {
+            if let Some(new_preferred) = self.peers.keys().next().copied() {
+                self.set_preferred_upstream(new_preferred);
+            } else {
+                warn!("no upstream peers!");
+                self.clear_preferred_upstream();
+            }
         }
         for (requested_hash, requested_slot) in peer.reqs {
             let announcers = self.chain.block_announcers(requested_slot, requested_hash);
@@ -214,6 +216,10 @@ impl NetworkManager {
         self.chain.handle_new_preferred_upstream(id);
     }
 
+    fn clear_preferred_upstream(&mut self) {
+        self.chain.clear_preferred_upstream();
+    }
+
     async fn publish_blocks(&mut self) -> Result<()> {
         while let Some((header, body, rolled_back)) = self.chain.next_unpublished_block() {
             self.block_sink.announce(header, body, rolled_back).await?;