chore: address PR feedback and fix failing unit test

Author: jcnelson

stackslib/src/net/stackerdb/sync.rs

@@ -226,24 +226,29 @@ impl<NC: NeighborComms> StackerDBSync<NC> {
             if self.last_eviction_time + 60 < get_epoch_time_secs() {
                 self.last_eviction_time = get_epoch_time_secs();
                 if self.replicas.len() > 0 {
-                    eviction_index = Some(thread_rng().gen::<usize>() % self.replicas.len());
+                    eviction_index = Some(thread_rng().gen_range(0..self.replicas.len()));
                 }
             }
 
-            let mut remove_naddr = None;
-            for (i, naddr) in self.replicas.iter().enumerate() {
-                if let Some(eviction_index) = eviction_index.as_ref() {
-                    if *eviction_index == i {
-                        debug!(
-                            "{:?}: {}: don't reuse connection for replica {:?}",
-                            network.get_local_peer(),
-                            &self.smart_contract_id,
-                            &naddr,
-                        );
-                        remove_naddr = Some(naddr.clone());
-                        continue;
-                    }
+            let remove_naddr = eviction_index.and_then(|idx| {
+                let removed = self.replicas.iter().nth(idx).cloned();
+                if let Some(naddr) = removed.as_ref() {
+                    debug!(
+                        "{:?}: {}: don't reuse connection for replica {:?}",
+                        network.get_local_peer(),
+                        &self.smart_contract_id,
+                        &naddr,
+                    );
                 }
+                removed
+            });
+
+            if let Some(naddr) = remove_naddr {
+                self.replicas.remove(&naddr);
+            }
+
+            // retain the remaining replica connections
+            for naddr in self.replicas.iter() {
                 if let Some(event_id) = network.get_event_id(&naddr.to_neighbor_key(network)) {
                     self.comms.pin_connection(event_id);
                     debug!(
@@ -255,9 +260,6 @@ impl<NC: NeighborComms> StackerDBSync<NC> {
                     );
                 }
             }
-            if let Some(naddr) = remove_naddr.take() {
-                self.replicas.remove(&naddr);
-            }
         }
 
         // reload from config

stackslib/src/net/stackerdb/tests/sync.rs

@@ -199,7 +199,14 @@ fn test_reconnect(network: &mut PeerNetwork) {
         .expect("FATAL: did not replace stacker dbs");
 
     for (_sc, stacker_db_sync) in stacker_db_syncs.iter_mut() {
-        stacker_db_sync.connect_begin(network).unwrap();
+        match stacker_db_sync.connect_begin(network) {
+            Ok(x) => {}
+            Err(net_error::PeerNotConnected) => {}
+            Err(net_error::NoSuchNeighbor) => {}
+            Err(e) => {
+                panic!("Failed to connect_begin: {:?}", &e);
+            }
+        }
     }
 
     network.stacker_db_syncs = Some(stacker_db_syncs);