From 07286c09119b7a86d886218467f482acaeb75a2a Mon Sep 17 00:00:00 2001
From: Christine Poerschke <cpoerschke@apache.org>
Date: Fri, 24 Mar 2023 17:16:37 +0000
Subject: [PATCH] SOLR-15446: Fix three off-by-one ArrayList initialCapacity
 choices when calling ZooKeeper.multi API. (#156)

Co-authored-by: Kevin Risden <krisden@apache.org>
---
 .../cloud/ShardLeaderElectionContextBase.java |  6 ++---
 .../org/apache/solr/cloud/ZkController.java   | 26 +++++++++----------
 2 files changed, 14 insertions(+), 18 deletions(-)

diff --git a/solr/core/src/java/org/apache/solr/cloud/ShardLeaderElectionContextBase.java b/solr/core/src/java/org/apache/solr/cloud/ShardLeaderElectionContextBase.java
index c38521bf35c..b99764bdc42 100644
--- a/solr/core/src/java/org/apache/solr/cloud/ShardLeaderElectionContextBase.java
+++ b/solr/core/src/java/org/apache/solr/cloud/ShardLeaderElectionContextBase.java
@@ -18,7 +18,6 @@
 package org.apache.solr.cloud;
 
 import java.lang.invoke.MethodHandles;
-import java.util.ArrayList;
 import java.util.List;
 import org.apache.solr.cloud.overseer.OverseerAction;
 import org.apache.solr.common.SolrException;
@@ -110,10 +109,9 @@ public void cancelElection() throws InterruptedException, KeeperException {
               "Removing leader registration node on cancel: {} {}",
               leaderPath,
               leaderZkNodeParentVersion);
-          List<Op> ops = new ArrayList<>(2);
           String parent = ZkMaintenanceUtils.getZkParent(leaderPath);
-          ops.add(Op.check(parent, leaderZkNodeParentVersion));
-          ops.add(Op.delete(leaderPath, -1));
+          List<Op> ops =
+              List.of(Op.check(parent, leaderZkNodeParentVersion), Op.delete(leaderPath, -1));
           zkClient.multi(ops, true);
         } catch (InterruptedException e) {
           throw e;
diff --git a/solr/core/src/java/org/apache/solr/cloud/ZkController.java b/solr/core/src/java/org/apache/solr/cloud/ZkController.java
index 246081bb7cc..a44cf3e8a6d 100644
--- a/solr/core/src/java/org/apache/solr/cloud/ZkController.java
+++ b/solr/core/src/java/org/apache/solr/cloud/ZkController.java
@@ -1217,7 +1217,8 @@ private void createEphemeralLiveNode() throws KeeperException, InterruptedExcept
     String nodeName = getNodeName();
     String nodePath = ZkStateReader.LIVE_NODES_ZKNODE + "/" + nodeName;
     log.info("Register node as live in ZooKeeper:{}", nodePath);
-    List<Op> ops = new ArrayList<>(2);
+    Map<NodeRoles.Role, String> roles = cc.nodeRoles.getRoles();
+    List<Op> ops = new ArrayList<>(roles.size() + 1);
     ops.add(
         Op.create(
             nodePath,
@@ -1226,16 +1227,14 @@ private void createEphemeralLiveNode() throws KeeperException, InterruptedExcept
             CreateMode.EPHEMERAL));
 
     // Create the roles node as well
-    cc.nodeRoles
-        .getRoles()
-        .forEach(
-            (role, mode) ->
-                ops.add(
-                    Op.create(
-                        NodeRoles.getZNodeForRoleMode(role, mode) + "/" + nodeName,
-                        null,
-                        zkClient.getZkACLProvider().getACLsToAdd(nodePath),
-                        CreateMode.EPHEMERAL)));
+    roles.forEach(
+        (role, mode) ->
+            ops.add(
+                Op.create(
+                    NodeRoles.getZNodeForRoleMode(role, mode) + "/" + nodeName,
+                    null,
+                    zkClient.getZkACLProvider().getACLsToAdd(nodePath),
+                    CreateMode.EPHEMERAL)));
 
     zkClient.multi(ops, true);
   }
@@ -1247,8 +1246,7 @@ public void removeEphemeralLiveNode() throws KeeperException, InterruptedExcepti
     String nodeName = getNodeName();
     String nodePath = ZkStateReader.LIVE_NODES_ZKNODE + "/" + nodeName;
     log.info("Remove node as live in ZooKeeper:{}", nodePath);
-    List<Op> ops = new ArrayList<>(2);
-    ops.add(Op.delete(nodePath, -1));
+    List<Op> ops = List.of(Op.delete(nodePath, -1));
 
     try {
       zkClient.multi(ops, true);
@@ -2947,7 +2945,7 @@ public void publishNodeAsDown(String nodeName) {
               && processedCollections.add(collName)
               && (coll = zkStateReader.getCollection(collName)) != null
               && coll.isPerReplicaState()) {
-            final List<String> replicasToDown = new ArrayList<>();
+            final List<String> replicasToDown = new ArrayList<>(coll.getSlicesMap().size());
             coll.forEachReplica(
                 (s, replica) -> {
                   if (replica.getNodeName().equals(nodeName)) {