From 88411eeabb69e0744c0baf117394ccf4a2e63d5c Mon Sep 17 00:00:00 2001
From: Ivan Kropotin <102463202+ivankrn@users.noreply.github.com>
Date: Fri, 3 Jul 2026 21:20:08 +0500
Subject: [PATCH] Fix broken double-checked locking in the R2DBC connection
 factory

Signed-off-by: Ivan Kropotin <102463202+ivankrn@users.noreply.github.com>
---
 .../TestcontainersR2DBCConnectionFactory.java     | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/modules/r2dbc/src/main/java/org/testcontainers/r2dbc/TestcontainersR2DBCConnectionFactory.java b/modules/r2dbc/src/main/java/org/testcontainers/r2dbc/TestcontainersR2DBCConnectionFactory.java
index bada076eec9..6cdc30b8305 100644
--- a/modules/r2dbc/src/main/java/org/testcontainers/r2dbc/TestcontainersR2DBCConnectionFactory.java
+++ b/modules/r2dbc/src/main/java/org/testcontainers/r2dbc/TestcontainersR2DBCConnectionFactory.java
@@ -31,7 +31,7 @@ class TestcontainersR2DBCConnectionFactory implements ConnectionFactory, Closeab
 
     private final R2DBCDatabaseContainerProvider containerProvider;
 
-    private CompletableFuture<R2DBCDatabaseContainer> future;
+    private volatile CompletableFuture<R2DBCDatabaseContainer> future;
 
     TestcontainersR2DBCConnectionFactory(ConnectionFactoryOptions options) {
         this.options = options;
@@ -47,10 +47,12 @@ class TestcontainersR2DBCConnectionFactory implements ConnectionFactory, Closeab
     @Override
     public Publisher<? extends Connection> create() {
         return new ConnectionPublisher(() -> {
-            if (future == null) {
+            CompletableFuture<R2DBCDatabaseContainer> futureRef = future;
+            if (futureRef == null) {
                 synchronized (this) {
-                    if (future == null) {
-                        future =
+                    futureRef = future;
+                    if (futureRef == null) {
+                        futureRef =
                             CompletableFuture.supplyAsync(
                                 () -> {
                                     R2DBCDatabaseContainer container = containerProvider.createContainer(options);
@@ -59,12 +61,11 @@ public Publisher<? extends Connection> create() {
                                 },
                                 EXECUTOR
                             );
+                        future = futureRef;
                     }
                 }
             }
-            return future.thenApply(it -> {
-                return ConnectionFactories.find(it.configure(options));
-            });
+            return futureRef.thenApply(it -> ConnectionFactories.find(it.configure(options)));
         });
     }