[Book][Security] constants are defined in the SecurityContextInterface

Author: xabbuh

book/security.rst

@@ -436,7 +436,7 @@ Next, create the controller that will display the login form::
 
     use Symfony\Bundle\FrameworkBundle\Controller\Controller;
     use Symfony\Component\HttpFoundation\Request;
-    use Symfony\Component\Security\Core\SecurityContext;
+    use Symfony\Component\Security\Core\SecurityContextInterface;
 
     class SecurityController extends Controller
     {
@@ -445,20 +445,20 @@ Next, create the controller that will display the login form::
             $session = $request->getSession();
 
             // get the login error if there is one
-            if ($request->attributes->has(SecurityContext::AUTHENTICATION_ERROR)) {
+            if ($request->attributes->has(SecurityContextInterface::AUTHENTICATION_ERROR)) {
                 $error = $request->attributes->get(
-                    SecurityContext::AUTHENTICATION_ERROR
+                    SecurityContextInterface::AUTHENTICATION_ERROR
                 );
             } else {
-                $error = $session->get(SecurityContext::AUTHENTICATION_ERROR);
-                $session->remove(SecurityContext::AUTHENTICATION_ERROR);
+                $error = $session->get(SecurityContextInterface::AUTHENTICATION_ERROR);
+                $session->remove(SecurityContextInterface::AUTHENTICATION_ERROR);
             }
 
             return $this->render(
                 'AcmeSecurityBundle:Security:login.html.twig',
                 array(
                     // last username entered by the user
-                    'last_username' => $session->get(SecurityContext::LAST_USERNAME),
+                    'last_username' => $session->get(SecurityContextInterface::LAST_USERNAME),
                     'error'         => $error,
                 )
             );