Merge reactor#2756 into 1.1.6

Signed-off-by: Oleh Dokuka <[email protected]>

reactor-netty-core/src/main/java/reactor/netty/channel/FluxReceive.java

@@ -18,7 +18,6 @@
 import java.nio.channels.ClosedChannelException;
 import java.util.ArrayDeque;
 import java.util.Queue;
-import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
 import java.util.function.IntConsumer;
 
@@ -61,9 +60,7 @@ final class FluxReceive extends Flux<Object> implements Subscription, Disposable
 
 	volatile IntConsumer receiverCancel;
 
-	volatile int once;
-	static final AtomicIntegerFieldUpdater<FluxReceive> ONCE =
-		AtomicIntegerFieldUpdater.newUpdater(FluxReceive.class, "once");
+	boolean subscribedOnce;
 
 	// Please note, in this specific case WIP is non-volatile since all operation that
 	// involves work-in-progress pattern is within Netty Event-Loops which guarantees
@@ -153,11 +150,12 @@ public void subscribe(CoreSubscriber<? super Object> s) {
 	}
 
 	final void startReceiver(CoreSubscriber<? super Object> s) {
-		if (once == 0 && ONCE.compareAndSet(this, 0, 1)) {
+		if (!subscribedOnce) {
+			subscribedOnce = true;
 			if (log.isDebugEnabled()) {
 				log.debug(format(channel, "{}: subscribing inbound receiver"), this);
 			}
-			if (inboundDone && getPending() == 0) {
+			if ((inboundDone && getPending() == 0) || isCancelled()) {
 				if (inboundError != null) {
 					Operators.error(s, inboundError);
 					return;

reactor-netty-core/src/test/java/reactor/netty/channel/FluxReceiveTest.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2019-2023 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.
+ * You may obtain a copy of the License at
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package reactor.netty.channel;
+
+import java.time.Duration;
+
+import io.netty.channel.embedded.EmbeddedChannel;
+import org.junit.jupiter.api.Test;
+import reactor.netty.NettyInbound;
+import reactor.netty.NettyOutbound;
+import reactor.test.subscriber.TestSubscriber;
+import reactor.test.util.RaceTestUtils;
+
+public class FluxReceiveTest {
+
+	@Test
+	void disposeAndSubscribeRaceTest() {
+		for (int i = 0; i < 100; i++) {
+			ChannelOperations<NettyInbound, NettyOutbound> operations =
+					new ChannelOperations<>(EmbeddedChannel::new, (connection, newState) -> {
+					});
+			FluxReceive receive = new FluxReceive(operations);
+			TestSubscriber<Object> subscriber = TestSubscriber.create();
+			RaceTestUtils.race(receive::dispose, () -> receive.subscribe(subscriber));
+
+			subscriber.block(Duration.ofSeconds(5));
+		}
+	}
+}