Call shutdown() in connect() on exception

to clean up the state build up by connect().

Related to SMACK-855 there is the possiblitiy of a stray (writer)
thread if, for example, tlsHandled.checkifSuccessOrWaitorThrow() in
XMPPTCPConnection.connectInternal() throws. This commit should prevent
that.

smack-bosh/src/main/java/org/jivesoftware/smack/bosh/XMPPBOSHConnection.java

@@ -263,6 +263,11 @@ public class XMPPBOSHConnection extends AbstractXMPPConnection {
             client = null;
         }
 
+        instantShutdown();
+    }
+
+    @Override
+    public void instantShutdown() {
         setWasAuthenticated();
         sessionID = null;
         done = true;

smack-core/src/main/java/org/jivesoftware/smack/AbstractXMPPConnection.java

@@ -405,6 +405,7 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
         tlsHandled.init();
         streamId = null;
 
+        try {
             // Perform the actual connection to the XMPP service
             connectInternal();
 
@@ -412,9 +413,12 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
             // from the server and throw an error. First check if we've already negotiated TLS
             // and are secure, however (features get parsed a second time after TLS is established).
             if (!isSecureConnection() && getConfiguration().getSecurityMode() == SecurityMode.required) {
-            shutdown();
                 throw new SecurityRequiredByClientException();
             }
+        } catch (SmackException | IOException | XMPPException | InterruptedException e) {
+            instantShutdown();
+            throw e;
+        }
 
         // Make note of the fact that we're now connected.
         connected = true;
@@ -763,6 +767,11 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
      */
     protected abstract void shutdown();
 
+    /**
+     * Performs an unclean disconnect and shutdown of the connection. Does not send a closing stream stanza.
+     */
+    public abstract void instantShutdown();
+
     @Override
     public void addConnectionListener(ConnectionListener connectionListener) {
         if (connectionListener == null) {

smack-core/src/test/java/org/jivesoftware/smack/DummyConnection.java

@@ -100,6 +100,11 @@ public class DummyConnection extends AbstractXMPPConnection {
         callConnectionClosedListener();
     }
 
+    @Override
+    public void instantShutdown() {
+        shutdown();
+    }
+
     @Override
     public boolean isSecureConnection() {
         return false;
@@ -226,4 +231,5 @@ public class DummyConnection extends AbstractXMPPConnection {
             }
         }
     }
+
 }

smack-tcp/src/main/java/org/jivesoftware/smack/tcp/XMPPTCPConnection.java

@@ -478,9 +478,7 @@ public class XMPPTCPConnection extends AbstractXMPPConnection {
         shutdown(false);
     }
 
-    /**
-     * Performs an unclean disconnect and shutdown of the connection. Does not send a closing stream stanza.
-     */
+    @Override
     public synchronized void instantShutdown() {
         shutdown(true);
     }