Fix and test for issue #330 - hang in disconnect

Author: Ian Craggs

org.eclipse.paho.client.mqttv3.test/src/test/java/org/eclipse/paho/client/mqttv3/test/BasicTest.java

@@ -21,6 +21,7 @@
 
 import org.eclipse.paho.client.mqttv3.IMqttClient;
 import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
+import org.eclipse.paho.client.mqttv3.IMqttAsyncClient;
 import org.eclipse.paho.client.mqttv3.MqttCallback;
 import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
 import org.eclipse.paho.client.mqttv3.MqttException;
@@ -326,6 +327,33 @@ public void testConnOptDefaults() throws Exception {
     Assert.assertNull(connOpts.getSSLProperties());
   }
 
+
+  @Test
+  public void test330() throws Exception {
+    String methodName = Utility.getMethodName();
+    LoggingUtilities.banner(log, cclass, methodName);
+
+    URI uri = new URI("tcp://iot.eclipse.org:1882");
+    IMqttAsyncClient client = clientFactory.createMqttAsyncClient(uri, "client-1");
+
+    MqttConnectOptions options = new MqttConnectOptions();
+    options.setAutomaticReconnect(true);
+    options.setUserName("foo");
+    options.setPassword("bar".toCharArray());
+    options.setConnectionTimeout(2);
+    client.connect(options);
+
+    Thread.sleep(1000);
+
+    try {
+    	  // this would deadlock before fix
+      client.disconnect(0).waitForCompletion();
+    } finally {
+      client.close();
+    }
+  }
+
+
   // -------------------------------------------------------------
   // Helper methods/classes
   // -------------------------------------------------------------

org.eclipse.paho.client.mqttv3/src/main/java-templates/org/eclipse/paho/client/mqttv3/internal/ClientComms.java

@@ -766,12 +766,19 @@ public void run() {
 			clientState.quiesce(quiesceTimeout);
 			try {
 				internalSend(disconnect, token);
-				token.internalTok.waitUntilSent();
+				// do not wait if the sender process is not running
+				if (sender != null && sender.isRunning()) {
+					token.internalTok.waitUntilSent();
+				}
 			}
 			catch (MqttException ex) {
 			}
 			finally {
 				token.internalTok.markComplete(null, null);
+				if (sender == null || !sender.isRunning()) {
+					// if the sender process is not running 
+					token.internalTok.notifyComplete();
+				}
 				shutdownConnection(token, null);
 			}
 		}