Issue #3377269: Warning: Undefined array key "id" in Drupal\jsonapi\Controller\EntityResource->patchIndividual()

core/modules/jsonapi/src/Controller/EntityResource.php

@@ -315,11 +315,11 @@ public function patchIndividual(ResourceType $resource_type, EntityInterface $en
 
     $body = Json::decode($request->getContent());
     $data = $body['data'];
-    if ($data['id'] != $entity->uuid()) {
+    if (!isset($data['id']) || $data['id'] != $entity->uuid()) {
       throw new BadRequestHttpException(sprintf(
         'The selected entity (%s) does not match the ID in the payload (%s).',
         $entity->uuid(),
-        $data['id']
+        $data['id'] ?? '',
       ));
     }
     $data += ['attributes' => [], 'relationships' => []];