Close asynchronously if called in NIO loop thread

src/main/java/com/rabbitmq/client/impl/AMQConnection.java

@@ -58,6 +58,8 @@ public class AMQConnection extends ShutdownNotifierComponent implements Connecti
     private final ScheduledExecutorService heartbeatExecutor;
     private final ExecutorService shutdownExecutor;
     private Thread mainLoopThread;
+    private final AtomicBoolean ioLoopThreadSet = new AtomicBoolean(false);
+    private volatile Thread ioLoopThread;
     private ThreadFactory threadFactory = Executors.defaultThreadFactory();
     private String id;
 
@@ -504,6 +506,7 @@ public void startMainLoop() {
         MainLoop loop = new MainLoop();
         final String name = "AMQP Connection " + getHostAddress() + ":" + getPort();
         mainLoopThread = Environment.newThread(threadFactory, loop, name);
+        ioLoopThread(mainLoopThread);
         mainLoopThread.start();
     }
 
@@ -1104,7 +1107,7 @@ public void close(int closeCode,
                       boolean abort)
         throws IOException
     {
-        boolean sync = !(Thread.currentThread() == mainLoopThread);
+        boolean sync = !(Thread.currentThread() == ioLoopThread);
 
         try {
             AMQP.Connection.Close reason =
@@ -1195,6 +1198,12 @@ public void setId(String id) {
         this.id = id;
     }
 
+    public void ioLoopThread(Thread thread) {
+        if (this.ioLoopThreadSet.compareAndSet(false, true)) {
+            this.ioLoopThread = thread;
+        }
+    }
+
     public int getChannelRpcTimeout() {
         return channelRpcTimeout;
     }

src/main/java/com/rabbitmq/client/impl/nio/NioLoop.java

@@ -157,6 +157,7 @@ public void run() {
 
                                     if (frame != null) {
                                         try {
+                                            state.getConnection().ioLoopThread(Thread.currentThread());
                                             boolean noProblem = state.getConnection().handleReadFrame(frame);
                                             if (noProblem && (!state.getConnection().isRunning() || state.getConnection().hasBrokerInitiatedShutdown())) {
                                                 // looks like the frame was Close-Ok or Close

src/test/java/com/rabbitmq/client/test/BlockedConnectionTest.java

@@ -0,0 +1,62 @@
+// Copyright (c) 2023 VMware, Inc. or its affiliates.  All rights reserved.
+//
+// This software, the RabbitMQ Java client library, is triple-licensed under the
+// Mozilla Public License 2.0 ("MPL"), the GNU General Public License version 2
+// ("GPL") and the Apache License version 2 ("ASL"). For the MPL, please see
+// LICENSE-MPL-RabbitMQ. For the GPL, please see LICENSE-GPL2.  For the ASL,
+// please see LICENSE-APACHE2.
+//
+// This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND,
+// either express or implied. See the LICENSE file for specific language governing
+// rights and limitations of this software.
+//
+// If you have any questions regarding licensing, please contact us at
+// [email protected].
+
+package com.rabbitmq.client.test;
+
+import static com.rabbitmq.client.test.TestUtils.LatchConditions.completed;
+import static com.rabbitmq.client.test.TestUtils.waitAtMost;
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.rabbitmq.client.Channel;
+import com.rabbitmq.client.Connection;
+import com.rabbitmq.client.ConnectionFactory;
+import java.util.concurrent.CountDownLatch;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+public class BlockedConnectionTest extends BrokerTestCase {
+
+  @ParameterizedTest
+  @ValueSource(booleans = {true, false})
+  void errorInBlockListenerShouldCloseConnection(boolean nio) throws Exception {
+    ConnectionFactory cf = TestUtils.connectionFactory();
+    if (nio) {
+      cf.useNio();
+    } else {
+      cf.useBlockingIo();
+    }
+    Connection c = cf.newConnection();
+    CountDownLatch shutdownLatch = new CountDownLatch(1);
+    c.addShutdownListener(cause -> shutdownLatch.countDown());
+    CountDownLatch blockedLatch = new CountDownLatch(1);
+    c.addBlockedListener(
+        reason -> {
+          blockedLatch.countDown();
+          throw new RuntimeException("error in blocked listener!");
+        },
+        () -> {});
+    try {
+      block();
+      Channel ch = c.createChannel();
+      ch.basicPublish("", "", null, "dummy".getBytes());
+      assertThat(blockedLatch).is(completed());
+    } finally {
+      unblock();
+    }
+    assertThat(shutdownLatch).is(completed());
+    waitAtMost(() -> !c.isOpen());
+  }
+
+}

src/test/java/com/rabbitmq/client/test/ClientTestSuite.java

@@ -73,7 +73,8 @@
     OAuth2ClientCredentialsGrantCredentialsProviderTest.class,
     RefreshCredentialsTest.class,
     AMQConnectionRefreshCredentialsTest.class,
-    ValueWriterTest.class
+    ValueWriterTest.class,
+    BlockedConnectionTest.class
 })
 public class ClientTestSuite {