From c29b0fed0c64dab3c5bf82a08ef21701b698af53 Mon Sep 17 00:00:00 2001
From: Violeta Georgieva <violeta.georgieva@broadcom.com>
Date: Tue, 7 Jan 2025 18:40:09 +0200
Subject: [PATCH] Http2Pool: Do not proceed with the acquisition if Borrower is
 cancelled (#3582)

---
 .../reactor/netty/http/client/Http2Pool.java  |  7 ++++-
 .../netty/http/client/Http2PoolTest.java      | 26 ++++++++++++++++++-
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/reactor-netty-http/src/main/java/reactor/netty/http/client/Http2Pool.java b/reactor-netty-http/src/main/java/reactor/netty/http/client/Http2Pool.java
index 8682651ebd..f262a3b5a4 100644
--- a/reactor-netty-http/src/main/java/reactor/netty/http/client/Http2Pool.java
+++ b/reactor-netty-http/src/main/java/reactor/netty/http/client/Http2Pool.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2024 VMware, Inc. or its affiliates, All Rights Reserved.
+ * Copyright (c) 2021-2025 VMware, Inc. or its affiliates, All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -332,6 +332,11 @@ else if (testEvictionPredicate(ref.slot)) {
 	}
 
 	void doAcquire(Borrower borrower) {
+		if (borrower.get()) {
+			// Borrower is cancelled, do nothing
+			return;
+		}
+
 		if (isDisposed()) {
 			borrower.fail(new PoolShutdownException());
 			return;
diff --git a/reactor-netty-http/src/test/java/reactor/netty/http/client/Http2PoolTest.java b/reactor-netty-http/src/test/java/reactor/netty/http/client/Http2PoolTest.java
index d91b476553..03ddc9f883 100644
--- a/reactor-netty-http/src/test/java/reactor/netty/http/client/Http2PoolTest.java
+++ b/reactor-netty-http/src/test/java/reactor/netty/http/client/Http2PoolTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2024 VMware, Inc. or its affiliates, All Rights Reserved.
+ * Copyright (c) 2021-2025 VMware, Inc. or its affiliates, All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,6 +22,7 @@
 import io.netty.handler.codec.http2.Http2FrameCodecBuilder;
 import io.netty.handler.codec.http2.Http2MultiplexHandler;
 import org.junit.jupiter.api.Test;
+import org.reactivestreams.Subscription;
 import reactor.core.Disposable;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -46,6 +47,7 @@
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.BiFunction;
 import java.util.concurrent.atomic.AtomicReference;
 
@@ -141,6 +143,28 @@ void acquireRelease() {
 		}
 	}
 
+	@Test
+	void doAcquireNotCalledIfBorrowerInScopeCancelledEarly() {
+		AtomicInteger allocator = new AtomicInteger();
+		PoolBuilder<Connection, PoolConfig<Connection>> poolBuilder =
+				PoolBuilder.from(Mono.fromSupplier(() -> {
+				               allocator.incrementAndGet();
+				               Channel channel = new EmbeddedChannel(
+				                   new TestChannelId(),
+				                   Http2FrameCodecBuilder.forClient().build());
+				               return Connection.from(channel);
+				           }));
+
+		Http2Pool http2Pool = poolBuilder.build(config -> new Http2Pool(config, null));
+
+		assertThat(allocator).as("before invoking acquire").hasValue(0);
+
+		// Borrower is in state cancelled before the actual acquisition
+		http2Pool.acquire().doOnSubscribe(Subscription::cancel).subscribe();
+
+		assertThat(allocator).as("after invoking acquire").hasValue(0);
+	}
+
 	@Test
 	void evictClosedConnection() throws Exception {
 		PoolBuilder<Connection, PoolConfig<Connection>> poolBuilder =