From cfe8dfa32252b280acf551d5343b95f88ca3806c Mon Sep 17 00:00:00 2001
From: Nikolaj Volgushev <n1v0lg@users.noreply.github.com>
Date: Tue, 17 Sep 2024 12:24:20 +0200
Subject: [PATCH] Properly remove security index recovered state consumer
 (#112927)

One of the security index state change listeners attempts to remove
itself once it has received the expected event.

However, since the consumer is a lambda, `this` in
`stateChangeListeners.remove(this);` actually refers to the enclosing
class instance (`SecurityIndexManager.this`) which results in a noop and
not an actual removal of the relevant consumer.

This PR fixes this by converting the lambda to an anonymous class.

It's technically a bug, but so minor that it doesn't warrant a bug
changelog IMO; so I'm labelling it a non-issue instead.
---
 .../security/support/SecurityIndexManager.java  | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/support/SecurityIndexManager.java b/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/support/SecurityIndexManager.java
index a6377c3ea789..a6c8de003c15 100644
--- a/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/support/SecurityIndexManager.java
+++ b/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/support/SecurityIndexManager.java
@@ -344,13 +344,16 @@ public class SecurityIndexManager implements ClusterStateListener {
     }
 
     public void onStateRecovered(Consumer<State> recoveredStateConsumer) {
-        BiConsumer<State, State> stateChangeListener = (previousState, nextState) -> {
-            boolean stateJustRecovered = previousState == UNRECOVERED_STATE && nextState != UNRECOVERED_STATE;
-            boolean stateAlreadyRecovered = previousState != UNRECOVERED_STATE;
-            if (stateJustRecovered) {
-                recoveredStateConsumer.accept(nextState);
-            } else if (stateAlreadyRecovered) {
-                stateChangeListeners.remove(this);
+        BiConsumer<State, State> stateChangeListener = new BiConsumer<>() {
+            @Override
+            public void accept(State previousState, State nextState) {
+                boolean stateJustRecovered = previousState == UNRECOVERED_STATE && nextState != UNRECOVERED_STATE;
+                boolean stateAlreadyRecovered = previousState != UNRECOVERED_STATE;
+                if (stateJustRecovered) {
+                    recoveredStateConsumer.accept(nextState);
+                } else if (stateAlreadyRecovered) {
+                    stateChangeListeners.remove(this);
+                }
             }
         };
         stateChangeListeners.add(stateChangeListener);