Fix PHPStan issues.

phpstan.neon

@@ -1,6 +1,3 @@
 parameters:
     ignoreErrors:
-        - '#Call to an undefined method Symfony\\Component\\Config\\Definition\\Builder\\NodeParentInterface::arrayNode()#'
-        - '#Call to an undefined method Symfony\\Component\\Config\\Definition\\Builder\\NodeParentInterface::scalarNode()#'
-        - '#Calling method scalarNode\(\) on possibly null value of type Symfony\\Component\\Config\\Definition\\Builder\\NodeParentInterface#'
-        - '#Cannot call method scalarNode() on Symfony\\Component\\Config\\Definition\\Builder\\NodeParentInterface|null.#'
+        - '#Class EcPhp\\CasBundle\\Security\\CasGuardAuthenticator#'

src/Controller/ProxyCallback.php

@@ -7,6 +7,7 @@
 use EcPhp\CasLib\CasInterface;
 use Symfony\Bridge\PsrHttpMessage\HttpFoundationFactoryInterface;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\Response;
 
 /**
  * Class ProxyCallback.
@@ -21,6 +22,10 @@ final class ProxyCallback extends AbstractController
      */
     public function __invoke(CasInterface $casProtocol, HttpFoundationFactoryInterface $httpFoundationFactory)
     {
-        return $httpFoundationFactory->createResponse($casProtocol->handleProxyCallback());
+        if (null !== $response = $casProtocol->handleProxyCallback()) {
+            return $httpFoundationFactory->createResponse($response);
+        }
+
+        return new Response('', Response::HTTP_INTERNAL_SERVER_ERROR);
     }
 }

src/DependencyInjection/Configuration.php

@@ -22,6 +22,7 @@ public function getConfigTreeBuilder()
         /** @var \Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition $rootNode */
         $rootNode = $treeBuilder->getRootNode();
 
+        /** @phpstan-ignore-next-line */
         $rootNode
             ->children()
             ->scalarNode('base_url')->defaultValue('')->end()

src/Security/CasGuardAuthenticator.php

@@ -135,6 +135,8 @@ public function onAuthenticationFailure(Request $request, AuthenticationExceptio
 
             return new RedirectResponse((string) $uri);
         }
+
+        return null;
     }
 
     /**
@@ -158,10 +160,16 @@ public function onAuthenticationSuccess(Request $request, TokenInterface $token,
      */
     public function onLogoutSuccess(Request $request)
     {
+        $response = $this
+            ->cas
+            ->logout();
+
+        if (null === $response) {
+            throw new AuthenticationException('Unable to trigger the logout procedure');
+        }
+
         return new RedirectResponse(
-            $this
-                ->cas
-                ->logout()
+            $response
                 ->getHeaderLine('location')
         );
     }
@@ -178,10 +186,16 @@ public function start(Request $request, ?AuthenticationException $authException
             );
         }
 
+        $response = $this
+            ->cas
+            ->login();
+
+        if (null === $response) {
+            throw new AuthenticationException('Unable to trigger the login procedure');
+        }
+
         return new RedirectResponse(
-            $this
-                ->cas
-                ->login()
+            $response
                 ->getHeaderLine('location')
         );
     }

src/Security/Core/User/CasUser.php

@@ -62,6 +62,7 @@ public function getAttributes(): array
      */
     public function getPassword()
     {
+        return null;
     }
 
     /**
@@ -85,6 +86,7 @@ public function getRoles()
      */
     public function getSalt()
     {
+        return null;
     }
 
     /**

src/Security/Core/User/CasUserInterface.php

@@ -15,7 +15,7 @@ interface CasUserInterface extends UserInterface
      * @param string $key
      * @param mixed $default
      *
-     * @return string|null
+     * @return mixed|null
      */
     public function get(string $key, $default = null);