Merge branch '5.4' into 6.0

* 5.4:
  [Security] Fix token user usage in SwitchUserListenerTest
  [Security] PassportInterface deprecations fixes
  [Security] Remove faulty legacy mark from SwitchUserListenerTest
  [Yaml] Add an --exclude option to lint:yaml command
  * Deprecated calling `FormErrorIterator::children()` if the current element is not iterable

Author: wouterj

CHANGELOG.md

@@ -21,6 +21,7 @@ CHANGELOG
 5.4
 ---
 
+ * Deprecate calling `FormErrorIterator::children()` if the current element is not iterable.
  * Allow to pass `TranslatableMessage` objects to the `help` option
 
 5.3

FormErrorIterator.php

@@ -13,6 +13,7 @@
 
 use Symfony\Component\Form\Exception\BadMethodCallException;
 use Symfony\Component\Form\Exception\InvalidArgumentException;
+use Symfony\Component\Form\Exception\LogicException;
 use Symfony\Component\Form\Exception\OutOfBoundsException;
 use Symfony\Component\Validator\ConstraintViolation;
 
@@ -186,11 +187,13 @@ public function hasChildren(): bool
         return current($this->errors) instanceof self;
     }
 
-    /**
-     * Alias of {@link current()}.
-     */
     public function getChildren(): self
     {
+        if (!$this->hasChildren()) {
+            trigger_deprecation('symfony/form', '5.4', 'Calling "%s()" if the current element is not iterable is deprecated, call "%s" to get the current element.', __METHOD__, self::class.'::current()');
+            // throw new LogicException(sprintf('The current element is not iterable. Use "%s" to get the current element.', self::class.'::current()'));
+        }
+
         return current($this->errors);
     }