From 86f75889a16273e33bf1da47df39a9c46673ad31 Mon Sep 17 00:00:00 2001
From: Violeta Georgieva <violeta.georgieva@broadcom.com>
Date: Wed, 12 Feb 2025 11:39:09 +0200
Subject: [PATCH 1/2] Annotate with Nullable, fields that can become null

Signed-off-by: Violeta Georgieva <violeta.georgieva@broadcom.com>
---
 .../src/main/java/reactor/pool/PoolBuilder.java  |  3 ++-
 .../main/java/reactor/pool/SimpleDequePool.java  | 16 +++++++++-------
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/reactor-pool/src/main/java/reactor/pool/PoolBuilder.java b/reactor-pool/src/main/java/reactor/pool/PoolBuilder.java
index d8496d3..2f1584d 100644
--- a/reactor-pool/src/main/java/reactor/pool/PoolBuilder.java
+++ b/reactor-pool/src/main/java/reactor/pool/PoolBuilder.java
@@ -26,6 +26,7 @@
 import java.util.function.Function;
 import java.util.function.Predicate;
 
+import org.jspecify.annotations.Nullable;
 import org.reactivestreams.Publisher;
 
 import reactor.core.Disposable;
@@ -67,7 +68,7 @@ public static <T> PoolBuilder<T, PoolConfig<T>> from(Publisher<? extends T> allo
 	final Mono<T>                          allocator;
 	final Function<PoolConfig<T>, CONF>    configModifier;
 	int                                    maxPending                  = -1;
-	AllocationStrategy                     allocationStrategy          = null;
+	@Nullable AllocationStrategy           allocationStrategy          = null;
 	Function<T, ? extends Publisher<Void>> releaseHandler              = noopHandler();
 	Function<T, ? extends Publisher<Void>> destroyHandler              = noopHandler();
 	BiPredicate<T, PooledRefMetadata>      evictionPredicate           = neverPredicate();
diff --git a/reactor-pool/src/main/java/reactor/pool/SimpleDequePool.java b/reactor-pool/src/main/java/reactor/pool/SimpleDequePool.java
index c39eb55..38381c7 100644
--- a/reactor-pool/src/main/java/reactor/pool/SimpleDequePool.java
+++ b/reactor-pool/src/main/java/reactor/pool/SimpleDequePool.java
@@ -68,7 +68,7 @@ public class SimpleDequePool<POOLABLE> extends AbstractPool<POOLABLE> {
 
 	volatile Deque<QueuePooledRef<POOLABLE>> idleResources;
 	@SuppressWarnings("rawtypes")
-	protected static final AtomicReferenceFieldUpdater<SimpleDequePool, Deque> IDLE_RESOURCES =
+	protected static final AtomicReferenceFieldUpdater<SimpleDequePool, @Nullable Deque> IDLE_RESOURCES =
 			AtomicReferenceFieldUpdater.newUpdater(SimpleDequePool.class, Deque.class, "idleResources");
 
 	volatile             int                                        acquired;
@@ -97,7 +97,7 @@ public class SimpleDequePool<POOLABLE> extends AbstractPool<POOLABLE> {
 	private static final AtomicIntegerFieldUpdater<SimpleDequePool> IDLE_SIZE =
 		AtomicIntegerFieldUpdater.newUpdater(SimpleDequePool.class, "idleSize");
 
-	Disposable evictionTask;
+	@Nullable Disposable evictionTask;
 
 	SimpleDequePool(PoolConfig<POOLABLE> poolConfig) {
 		super(poolConfig, Loggers.getLogger(SimpleDequePool.class));
@@ -187,7 +187,9 @@ public Mono<Void> disposeLater() {
 					PENDING.getAndSet(this, TERMINATED);
 			if (q != TERMINATED) {
 				//stop reaper thread
-				this.evictionTask.dispose();
+				if (this.evictionTask != null) {
+					this.evictionTask.dispose();
+				}
 
 				Borrower<POOLABLE> p;
 				while ((p = q.pollFirst()) != null) {
@@ -750,8 +752,8 @@ private static final class QueuePoolRecyclerInner<T>
 		final SimpleDequePool<T>           pool;
 
 		//poolable can be checked for null to protect against protocol errors
-		QueuePooledRef<T> pooledRef;
-		Subscription                      upstream;
+		@Nullable QueuePooledRef<T>       pooledRef;
+		@Nullable Subscription            upstream;
 		long                              start;
 
 		//once protects against multiple requests
@@ -829,7 +831,7 @@ public void onSubscribe(Subscription s) {
 
 		@Override
 		public void request(long l) {
-			if (Operators.validate(l)) {
+			if (upstream != null && Operators.validate(l)) {
 				upstream.request(l);
 				// we decrement ACQUIRED EXACTLY ONCE to indicate that the poolable was released by the user
 				if (ONCE.compareAndSet(this, 0, 1)) {
@@ -867,7 +869,7 @@ private static final class QueuePoolRecyclerMono<T> extends Mono<Void>
 			implements Scannable {
 
 		final Publisher<Void>                                    source;
-		final AtomicReference<QueuePooledRef<T>> slotRef;
+		final AtomicReference<@Nullable QueuePooledRef<T>> slotRef;
 
 		QueuePoolRecyclerMono(Publisher<Void> source, QueuePooledRef<T> poolSlot) {
 			this.source = source;

From c2db5a5c065a4910675812b53079a7d83cb3cda1 Mon Sep 17 00:00:00 2001
From: Violeta Georgieva <violeta.georgieva@broadcom.com>
Date: Wed, 12 Feb 2025 12:14:59 +0200
Subject: [PATCH 2/2] Address feedback

Signed-off-by: Violeta Georgieva <violeta.georgieva@broadcom.com>
---
 reactor-pool/src/main/java/reactor/pool/SimpleDequePool.java | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/reactor-pool/src/main/java/reactor/pool/SimpleDequePool.java b/reactor-pool/src/main/java/reactor/pool/SimpleDequePool.java
index 38381c7..adda097 100644
--- a/reactor-pool/src/main/java/reactor/pool/SimpleDequePool.java
+++ b/reactor-pool/src/main/java/reactor/pool/SimpleDequePool.java
@@ -831,7 +831,8 @@ public void onSubscribe(Subscription s) {
 
 		@Override
 		public void request(long l) {
-			if (upstream != null && Operators.validate(l)) {
+			assert upstream != null;
+			if (Operators.validate(l)) {
 				upstream.request(l);
 				// we decrement ACQUIRED EXACTLY ONCE to indicate that the poolable was released by the user
 				if (ONCE.compareAndSet(this, 0, 1)) {