Implement UserInterface to work around Symfony core changes

src/Resources/contao/classes/BackendUser.php

@@ -543,4 +543,23 @@ public function navigation($blnShowAll=false)
 
 		return $arrModules;
 	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function getRoles()
+	{
+		// User not loaded
+		if (!$this->intId) {
+			return [];
+		}
+
+		$roles = ['ROLE_USER'];
+
+		if ($this->isAdmin) {
+			$roles[] = 'ROLE_ADMIN';
+		}
+
+		return $roles;
+	}
 }

src/Resources/contao/classes/FrontendUser.php

@@ -305,4 +305,17 @@ protected function setUserFromDb()
 			}
 		}
 	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function getRoles()
+	{
+		// User not loaded
+		if (!$this->intId) {
+			return [];
+		}
+
+		return ['ROLE_MEMBER'];
+	}
 }

src/Resources/contao/library/Contao/User.php

@@ -11,6 +11,7 @@
 namespace Contao;
 
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Security\Core\User\UserInterface;
 use Symfony\Component\Security\Http\Session\SessionAuthenticationStrategy;
 
 
@@ -95,7 +96,7 @@
  *
  * @author Leo Feyer <https://github.com/leofeyer>
  */
-abstract class User extends \System
+abstract class User extends \System implements UserInterface
 {
 
 	/**
@@ -730,6 +731,38 @@ public function isMemberOf($id)
 		return false;
 	}
 
+	/**
+	 * {@inheritdoc}
+	 */
+	public function getPassword()
+	{
+		return '';
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function getSalt()
+	{
+		return null;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function getUsername()
+	{
+		return $this->username;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function eraseCredentials()
+	{
+		// do nothing
+	}
+
 
 	/**
 	 * Set all user properties from a database record