https://issues.apache.org/jira/browse/AMQ-6579

Remove incorrect dispatch counter increment on message expiration in
TopicSubscription when a pending limit strategy is set

(cherry picked from commit d0c95146c37f96ca69e1fe82c4b2fe9208f8184e)

activemq-broker/src/main/java/org/apache/activemq/broker/region/TopicSubscription.java

@@ -232,7 +232,6 @@ public class TopicSubscription extends AbstractSubscription {
                 node.decrementReferenceCount();
                 if (node.isExpired()) {
                     matched.remove();
-                    getSubscriptionStatistics().getDispatched().increment();
                     node.decrementReferenceCount();
                     if (broker.isExpired(node)) {
                         ((Destination) node.getRegionDestination()).getDestinationStatistics().getExpired().increment();

activemq-unit-tests/src/test/java/org/apache/activemq/bugs/AMQ6579Test.java

@@ -0,0 +1,128 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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
+ *
+ *      http://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 org.apache.activemq.bugs;
+
+import static org.junit.Assert.assertEquals;
+
+import javax.jms.Connection;
+import javax.jms.JMSException;
+import javax.jms.MessageConsumer;
+import javax.jms.MessageProducer;
+import javax.jms.Session;
+import javax.jms.TextMessage;
+
+import org.apache.activemq.ActiveMQConnectionFactory;
+import org.apache.activemq.ActiveMQSession;
+import org.apache.activemq.TestSupport;
+import org.apache.activemq.broker.BrokerService;
+import org.apache.activemq.broker.TransportConnector;
+import org.apache.activemq.broker.region.Destination;
+import org.apache.activemq.broker.region.policy.ConstantPendingMessageLimitStrategy;
+import org.apache.activemq.broker.region.policy.PolicyEntry;
+import org.apache.activemq.broker.region.policy.PolicyMap;
+import org.apache.activemq.command.ActiveMQTopic;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class AMQ6579Test {
+
+    protected BrokerService brokerService;
+    protected Connection connection;
+    protected Session session;
+    protected ActiveMQTopic topic;
+    protected Destination amqDestination;
+    protected MessageConsumer consumer;
+
+    @Before
+    public void setUp() throws Exception {
+        brokerService = new BrokerService();
+        brokerService.setPersistent(false);
+
+        PolicyEntry policy = new PolicyEntry();
+        policy.setTopicPrefetch(5);
+        ConstantPendingMessageLimitStrategy pendingMessageLimitStrategy = new ConstantPendingMessageLimitStrategy();
+        pendingMessageLimitStrategy.setLimit(5);
+        policy.setPendingMessageLimitStrategy(pendingMessageLimitStrategy);
+        PolicyMap pMap = new PolicyMap();
+        pMap.setDefaultEntry(policy);
+        brokerService.setDestinationPolicy(pMap);
+
+        TransportConnector tcp = brokerService.addConnector("tcp://localhost:0");
+        brokerService.start();
+        connection = new ActiveMQConnectionFactory(tcp.getPublishableConnectString()).createConnection();
+        connection.start();
+        session = connection.createSession(false, ActiveMQSession.AUTO_ACKNOWLEDGE);
+        topic = new ActiveMQTopic("test.topic");
+        consumer = session.createConsumer(topic);
+        amqDestination = TestSupport.getDestination(brokerService, topic);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        if (connection != null) {
+            connection.close();
+        }
+        brokerService.stop();
+    }
+
+    /**
+     * Test that messages are expired properly on a topic subscription when a
+     * constant pending limit strategy is set and that future messages are
+     * dispatched properly so that the consumer isn't blocked
+     *
+     * @throws Exception
+     */
+    @Test(timeout = 10000)
+    public void testExpireWithPendingLimitStrategy() throws Exception {
+
+        //Send 5 messages that are not expired to fill up prefetch
+        //followed by 5 messages that can be expired
+        //then another 5 messages that won't expire
+        //Make sure 10 messages are received
+        sendMessages(5, 0);
+        sendMessages(5, 1);
+        sendMessages(5, 0);
+
+        //should get 10 messages as the middle 5 should expire
+        assertEquals(10, receiveMessages());
+    }
+
+    /**
+     * This method will generate random sized messages up to 150000 bytes.
+     *
+     * @param count
+     * @throws JMSException
+     */
+    protected void sendMessages(int count, int expire) throws JMSException {
+        MessageProducer producer = session.createProducer(topic);
+        producer.setTimeToLive(expire);
+        for (int i = 0; i < count; i++) {
+            TextMessage textMessage = session.createTextMessage("test");
+            producer.send(textMessage);
+        }
+    }
+
+    protected int receiveMessages() throws JMSException {
+        int count = 0;
+        while (consumer.receive(500) != null) {
+            count++;
+        }
+        return count;
+    }
+
+}