small refactorings to make the code more readable

protocols/gossipsub/src/behaviour.rs

@@ -2817,24 +2817,27 @@ where
             .connections
             .push(connection_id);
 
-        if other_established == 0 {
-            // Ignore connections from blacklisted peers.
-            if self.blacklisted_peers.contains(&peer_id) {
-                tracing::debug!(peer=%peer_id, "Ignoring connection from blacklisted peer");
-            } else {
-                tracing::debug!(peer=%peer_id, "New peer connected");
-                // We need to send our subscriptions to the newly-connected node.
-                for topic_hash in self.mesh.keys().cloned().collect::<Vec<_>>() {
-                    self.send_message(peer_id, RpcOut::Subscribe(topic_hash));
-                }
-            }
+        if other_established > 0 {
+            return; // Not our first connection to this peer, hence nothing to do.
+        }
+
+        // Ignore connections from blacklisted peers.
+        if self.blacklisted_peers.contains(&peer_id) {
+            tracing::debug!(peer=%peer_id, "Ignoring connection from blacklisted peer");
+            return;
+        }
 
-            // Insert an empty set of the topics of this peer until known.
-            self.peer_topics.insert(peer_id, Default::default());
+        tracing::debug!(peer=%peer_id, "New peer connected");
+        // We need to send our subscriptions to the newly-connected node.
+        for topic_hash in self.mesh.keys().cloned().collect::<Vec<_>>() {
+            self.send_message(peer_id, RpcOut::Subscribe(topic_hash));
+        }
 
-            if let Some((peer_score, ..)) = &mut self.peer_score {
-                peer_score.add_peer(peer_id);
-            }
+        // Insert an empty set of the topics of this peer until known.
+        self.peer_topics.insert(peer_id, Default::default());
+
+        if let Some((peer_score, ..)) = &mut self.peer_score {
+            peer_score.add_peer(peer_id);
         }
     }