[person] prevent circular references in PersonDocGenNormalizer

src/Bundle/ChillPersonBundle/Serializer/Normalizer/PersonDocGenNormalizer.php

@@ -23,6 +23,7 @@ use Chill\PersonBundle\Repository\Relationships\RelationshipRepository;
 use Chill\PersonBundle\Templating\Entity\PersonRenderInterface;
 use DateTimeInterface;
 use Doctrine\Common\Collections\ArrayCollection;
+use Doctrine\Common\DataFixtures\Exception\CircularReferenceException;
 use libphonenumber\PhoneNumber;
 use Symfony\Component\Serializer\Exception\UnexpectedValueException;
 use Symfony\Component\Serializer\Normalizer\AbstractNormalizer;
@@ -52,6 +53,8 @@ class PersonDocGenNormalizer implements
 
     private TranslatorInterface $translator;
 
+    private const CIRCULAR_KEY = 'person:circular';
+
     public function __construct(
         PersonRenderInterface $personRender,
         RelationshipRepository $relationshipRepository,
@@ -68,6 +71,17 @@ class PersonDocGenNormalizer implements
 
     public function normalize($person, $format = null, array $context = [])
     {
+
+        try {
+            $context = $this->addCircularToContext($person, $context);
+        } catch (CircularReferenceException $circularReferenceException) {
+            return [
+                'isNull' => true,
+                'isCircular' => true,
+                'text' => ''
+            ];
+        }
+
         /** @var Person $person */
         $dateContext = $context;
         $dateContext['docgen:expects'] = DateTimeInterface::class;
@@ -178,6 +192,36 @@ class PersonDocGenNormalizer implements
             );
     }
 
+    private function addCircularToContext($person, $context) {
+        if (null === $person) {
+            $key = 'n';
+        } else {
+            $key = spl_object_hash($person);
+        }
+
+        if (!\array_key_exists(self::CIRCULAR_KEY, $context)) {
+            $context[self::CIRCULAR_KEY] = [$key];
+
+            return $context;
+        }
+
+        $occurences = array_reduce($context[self::CIRCULAR_KEY], function ($carry, $item) use ($key) {
+            if ($key === $item) {
+                $carry++;
+            }
+            return $carry;
+        }, 0);
+
+        if (2 <= $occurences) {
+            throw new CircularReferenceException();
+        }
+
+        $context[self::CIRCULAR_KEY][] = $key;
+
+        return $context;
+    }
+
+
     private function hasGroup($context, string $group): bool
     {
         $groups = $context[AbstractNormalizer::GROUPS] ?? [];