From b3684377cd1cfb5233f96f99515f078e7f2f3c1f Mon Sep 17 00:00:00 2001
From: Raphael Michel <mail@raphaelmichel.de>
Date: Wed, 17 Apr 2019 15:40:25 +0200
Subject: [PATCH] Fix crash in item validation

Fixes Sentry PRETIXEU-10B
---
 src/pretix/base/models/items.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/pretix/base/models/items.py b/src/pretix/base/models/items.py
index 22d584c5e6..618ea3a9ac 100644
--- a/src/pretix/base/models/items.py
+++ b/src/pretix/base/models/items.py
@@ -1391,7 +1391,7 @@ class Quota(LoggedModel):
 
     @staticmethod
     def clean_variations(items, variations):
-        for variation in variations:
+        for variation in (variations or []):
             if variation.item not in items:
                 raise ValidationError(_('All variations must belong to an item contained in the items list.'))
                 break