From 2d68ae5b1883d5ffc40c0897cd20428b4df89d02 Mon Sep 17 00:00:00 2001
From: Niket Goel <niket-goel@users.noreply.github.com>
Date: Mon, 8 Nov 2021 13:06:04 -0800
Subject: [PATCH] MINOR: Adding a constant to denote UNKNOWN leader in
 LeaderAndEpoch

---
 raft/src/main/java/org/apache/kafka/raft/KafkaRaftClient.java | 2 +-
 raft/src/main/java/org/apache/kafka/raft/LeaderAndEpoch.java  | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/raft/src/main/java/org/apache/kafka/raft/KafkaRaftClient.java b/raft/src/main/java/org/apache/kafka/raft/KafkaRaftClient.java
index 24acb5ecdba76..180573d738b40 100644
--- a/raft/src/main/java/org/apache/kafka/raft/KafkaRaftClient.java
+++ b/raft/src/main/java/org/apache/kafka/raft/KafkaRaftClient.java
@@ -2448,7 +2448,7 @@ private static <T> Registration<T> unregister(Listener<T> listener) {
     private final class ListenerContext implements CloseListener<BatchReader<T>> {
         private final RaftClient.Listener<T> listener;
         // This field is used only by the Raft IO thread
-        private LeaderAndEpoch lastFiredLeaderChange = new LeaderAndEpoch(OptionalInt.empty(), 0);
+        private LeaderAndEpoch lastFiredLeaderChange = LeaderAndEpoch.UNKNOWN;
 
         // These fields are visible to both the Raft IO thread and the listener
         // and are protected through synchronization on this ListenerContext instance
diff --git a/raft/src/main/java/org/apache/kafka/raft/LeaderAndEpoch.java b/raft/src/main/java/org/apache/kafka/raft/LeaderAndEpoch.java
index fee0c2feaf5c7..459fd30e82e25 100644
--- a/raft/src/main/java/org/apache/kafka/raft/LeaderAndEpoch.java
+++ b/raft/src/main/java/org/apache/kafka/raft/LeaderAndEpoch.java
@@ -22,6 +22,7 @@
 public class LeaderAndEpoch {
     private final OptionalInt leaderId;
     private final int epoch;
+    public static final LeaderAndEpoch UNKNOWN = new LeaderAndEpoch(OptionalInt.empty(), 0);
 
     public LeaderAndEpoch(OptionalInt leaderId, int epoch) {
         this.leaderId = Objects.requireNonNull(leaderId);