From 6e918e4a3481dde0923b2abcf3cf6f6a24dbedca Mon Sep 17 00:00:00 2001
From: Justin Starry <justin@anza.xyz>
Date: Thu, 15 Aug 2024 23:50:27 +0000
Subject: [PATCH] feedback

---
 core/src/next_leader.rs    | 18 ++++++++----------
 core/src/voting_service.rs |  9 +++++++--
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/core/src/next_leader.rs b/core/src/next_leader.rs
index 70261531437917..7e77ecd869e4a1 100644
--- a/core/src/next_leader.rs
+++ b/core/src/next_leader.rs
@@ -7,31 +7,29 @@ use {
 };
 
 /// Returns a list of tpu vote sockets for the leaders of the next N fanout
-/// slots. Leaders are deduped but the resulting list could have duplicate
-/// sockets if two different leaders share the same tpu vote socket.
+/// slots. Leaders and sockets are deduped.
 pub(crate) fn upcoming_leader_tpu_vote_sockets(
     cluster_info: &ClusterInfo,
     poh_recorder: &RwLock<PohRecorder>,
-    fanout_slots: usize,
+    fanout_slots: u64,
 ) -> Vec<SocketAddr> {
     let upcoming_leaders = {
-        let mut upcoming_leaders = Vec::with_capacity(fanout_slots);
         let poh_recorder = poh_recorder.read().unwrap();
-        for n_slots in 1..=fanout_slots {
-            upcoming_leaders.push(poh_recorder.leader_after_n_slots(n_slots as u64));
-        }
-        upcoming_leaders
+        (1..=fanout_slots)
+            .filter_map(|n_slots| poh_recorder.leader_after_n_slots(n_slots))
+            .collect_vec()
     };
 
     upcoming_leaders
         .into_iter()
-        .flatten()
-        .unique()
+        .dedup()
         .filter_map(|leader_pubkey| {
             cluster_info
                 .lookup_contact_info(&leader_pubkey, ContactInfo::tpu_vote)?
                 .ok()
         })
+        // dedup again since leaders could potentially share the same tpu vote socket
+        .dedup()
         .collect()
 }
 
diff --git a/core/src/voting_service.rs b/core/src/voting_service.rs
index dc60ec49b5ce37..14443ab9c7947c 100644
--- a/core/src/voting_service.rs
+++ b/core/src/voting_service.rs
@@ -7,7 +7,10 @@ use {
     solana_gossip::cluster_info::ClusterInfo,
     solana_measure::measure::Measure,
     solana_poh::poh_recorder::PohRecorder,
-    solana_sdk::{clock::Slot, transaction::Transaction},
+    solana_sdk::{
+        clock::{Slot, FORWARD_TRANSACTIONS_TO_LEADER_AT_SLOT_OFFSET},
+        transaction::Transaction,
+    },
     std::{
         sync::{Arc, RwLock},
         thread::{self, Builder, JoinHandle},
@@ -79,7 +82,9 @@ impl VotingService {
         }
 
         // Attempt to send our vote transaction to the leaders for the next few slots
-        const UPCOMING_LEADER_FANOUT_SLOTS: usize = 2;
+        const UPCOMING_LEADER_FANOUT_SLOTS: u64 = FORWARD_TRANSACTIONS_TO_LEADER_AT_SLOT_OFFSET;
+        #[cfg(test)]
+        static_assertions::const_assert_eq!(UPCOMING_LEADER_FANOUT_SLOTS, 2);
         let upcoming_leader_sockets = upcoming_leader_tpu_vote_sockets(
             cluster_info,
             poh_recorder,