From 242bfc00231eb7e7176fba2ab626b38600144c88 Mon Sep 17 00:00:00 2001
From: Raphael Michel <mail@raphaelmichel.de>
Date: Tue, 1 Dec 2020 17:06:03 +0100
Subject: [PATCH] CartPosition API: Fix setting a custom cart ID

---
 src/pretix/api/serializers/cart.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/pretix/api/serializers/cart.py b/src/pretix/api/serializers/cart.py
index 6c6963827..cae4b92af 100644
--- a/src/pretix/api/serializers/cart.py
+++ b/src/pretix/api/serializers/cart.py
@@ -107,6 +107,7 @@ class CartPositionCreateSerializer(I18nAwareModelSerializer):
     def validate_cart_id(self, cid):
         if cid and not cid.endswith('@api'):
             raise ValidationError('Cart ID should end in @api or be empty.')
+        return cid
 
     def validate_item(self, item):
         if item.event != self.context['event']: