Check for default leader and use cmp::max for a bit nicer code (#779)

src/crdt.rs

@@ -328,7 +328,14 @@ impl Crdt {
         &self.table[&self.me]
     }
     pub fn leader_data(&self) -> Option<&NodeInfo> {
-        self.table.get(&(self.table[&self.me].leader_id))
+        let leader_id = self.table[&self.me].leader_id;
+
+        // leader_id can be 0s from network entry point
+        if leader_id == PublicKey::default() {
+            return None;
+        }
+
+        self.table.get(&leader_id)
     }
 
     pub fn set_leader(&mut self, key: PublicKey) -> () {
@@ -1817,6 +1824,7 @@ mod tests {
         crdt.purge(now + GOSSIP_PURGE_MILLIS + 1);
         assert_eq!(len as usize - 1, crdt.table.len());
         assert_eq!(crdt.my_data().leader_id, PublicKey::default());
+        assert!(crdt.leader_data().is_none());
     }
 
     /// test window requests respond with the right blob, and do not overrun
@@ -1956,4 +1964,21 @@ mod tests {
         let bad_address_multicast = "224.254.0.0:1234".parse().unwrap();
         assert!(!Crdt::is_valid_address(bad_address_multicast));
     }
+
+    #[test]
+    fn test_default_leader() {
+        logger::setup();
+        let node_info = NodeInfo::new(
+            KeyPair::new().pubkey(),
+            "127.0.0.1:1234".parse().unwrap(),
+            "127.0.0.1:1235".parse().unwrap(),
+            "127.0.0.1:1236".parse().unwrap(),
+            "127.0.0.1:1237".parse().unwrap(),
+            "127.0.0.1:1238".parse().unwrap(),
+        );
+        let mut crdt = Crdt::new(node_info).unwrap();
+        let network_entry_point = NodeInfo::new_entry_point("127.0.0.1:1239".parse().unwrap());
+        crdt.insert(&network_entry_point);
+        assert!(crdt.leader_data().is_none());
+    }
 }

tests/multinode.rs

@@ -16,6 +16,7 @@ use solana::signature::{KeyPair, KeyPairUtil, PublicKey};
 use solana::streamer::default_window;
 use solana::thin_client::ThinClient;
 use solana::timing::duration_as_s;
+use std::cmp::max;
 use std::env;
 use std::fs::File;
 use std::net::UdpSocket;
@@ -503,9 +504,7 @@ fn test_multi_node_dynamic_network() {
                 );
                 let bal = getbal.unwrap_or(0);
                 let distance = (leader_balance - bal) / 500;
-                if distance > max_distance {
-                    max_distance = distance;
-                }
+                max_distance = max(distance, max_distance);
                 total_distance += distance;
                 if let Some(bal) = getbal {
                     if bal == leader_balance {