Avoid relying on the getSalt method when using UserInterface

This method is not guaranted to be there if the Symfony interface does
not include it (which it won't do on Symfony 6).

Author: stof

Util/HashingPasswordUpdater.php

@@ -40,13 +40,14 @@ public function hashPassword(UserInterface $user)
         $hasher = $this->passwordHasherFactory->getPasswordHasher($user);
 
         if (!$hasher instanceof LegacyPasswordHasherInterface) {
-            $user->setSalt(null);
+            $salt = null;
         } else {
             $salt = rtrim(str_replace('+', '.', base64_encode(random_bytes(32))), '=');
-            $user->setSalt($salt);
         }
 
-        $hashedPassword = $hasher->hash($plainPassword, $user->getSalt());
+        $user->setSalt($salt);
+
+        $hashedPassword = $hasher->hash($plainPassword, $salt);
         $user->setPassword($hashedPassword);
         $user->eraseCredentials();
     }

Util/PasswordUpdater.php

@@ -41,13 +41,13 @@ public function hashPassword(UserInterface $user)
         $encoder = $this->encoderFactory->getEncoder($user);
 
         if ($encoder instanceof BCryptPasswordEncoder || $encoder instanceof SelfSaltingEncoderInterface) {
-            $user->setSalt(null);
+            $salt = null;
         } else {
             $salt = rtrim(str_replace('+', '.', base64_encode(random_bytes(32))), '=');
-            $user->setSalt($salt);
         }
+        $user->setSalt($salt);
 
-        $hashedPassword = $encoder->encodePassword($plainPassword, $user->getSalt());
+        $hashedPassword = $encoder->encodePassword($plainPassword, $salt);
         $user->setPassword($hashedPassword);
         $user->eraseCredentials();
     }