From e03b605684997e5d1f3a3a48b0a72065e9e631a3 Mon Sep 17 00:00:00 2001
From: Dmitriy Tverdiakov <dmitriy.tverdiakov@neo4j.com>
Date: Tue, 29 Oct 2024 11:28:03 +0000
Subject: [PATCH] Make sure PooledBoltConnection.close is thread-safe

---
 .../bolt/pooledimpl/PooledBoltConnection.java        | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/driver/src/main/java/org/neo4j/driver/internal/bolt/pooledimpl/PooledBoltConnection.java b/driver/src/main/java/org/neo4j/driver/internal/bolt/pooledimpl/PooledBoltConnection.java
index 267485a641..5395759fb5 100644
--- a/driver/src/main/java/org/neo4j/driver/internal/bolt/pooledimpl/PooledBoltConnection.java
+++ b/driver/src/main/java/org/neo4j/driver/internal/bolt/pooledimpl/PooledBoltConnection.java
@@ -269,9 +269,17 @@ public CompletionStage<Void> forceClose(String reason) {
 
     @Override
     public CompletionStage<Void> close() {
-        if (closeFuture == null) {
-            closeFuture = new CompletableFuture<>();
+        CompletableFuture<Void> closeFuture;
+        var close = false;
+        synchronized (this) {
+            if (this.closeFuture == null) {
+                this.closeFuture = new CompletableFuture<>();
+                close = true;
+            }
+            closeFuture = this.closeFuture;
+        }
 
+        if (close) {
             if (delegate.state() == BoltConnectionState.CLOSED) {
                 purgeRunnable.run();
                 closeFuture.complete(null);