Missing key model in Wishlist value data

Author: XxXgeoXxX

app/code/Magento/WishlistGraphQl/Model/Resolver/WishlistResolver.php

@@ -13,6 +13,7 @@
 use Magento\Wishlist\Model\ResourceModel\Wishlist as WishlistResourceModel;
 use Magento\Wishlist\Model\Wishlist;
 use Magento\Wishlist\Model\WishlistFactory;
+use Magento\Framework\GraphQl\Exception\GraphQlAuthorizationException;
 
 /**
  * Fetches the Wishlist data according to the GraphQL schema
@@ -51,6 +52,10 @@ public function resolve(
     ) {
         $customerId = $context->getUserId();
 
+        /* Guest checking */
+        if (!$customerId && 0 === $customerId) {
+            throw new GraphQlAuthorizationException(__('The current user cannot perform operations on wishlist'));
+        }
         /** @var Wishlist $wishlist */
         $wishlist = $this->wishlistFactory->create();
         $this->wishlistResource->load($wishlist, $customerId, 'customer_id');

dev/tests/api-functional/testsuite/Magento/GraphQl/Wishlist/WishlistTest.php

@@ -93,6 +93,36 @@ public function testGetCustomerWishlist(): void
         $this->assertEquals($wishlistItemProduct->getName(), $response['wishlist']['items'][0]['product']['name']);
     }
 
+    /**
+     * @expectedException \Exception
+     * @expectedExceptionMessage The current user cannot perform operations on wishlist
+     */
+    public function testGetGuestWishlist()
+    {
+        $query =
+            <<<QUERY
+{
+  wishlist {
+    items_count
+    name
+    sharing_code
+    updated_at
+    items {
+      id
+      qty
+      description
+      added_at
+      product {
+        sku
+        name
+      }
+    }
+  }
+}
+QUERY;
+        $this->graphQlQuery($query);
+    }
+
     /**
      * @param string $email
      * @param string $password