CartManager: Do not try to extend positions while they are being removed

src/pretix/base/services/cart.py

@@ -276,6 +276,10 @@ class CartManager:
         err = None
         changed_prices = {}
         for cp in expired:
+            removed_positions = {op.position.pk for op in self._operations if isinstance(op, self.RemoveOperation)}
+            if cp.pk in removed_positions or (cp.addon_to_id and cp.addon_to_id in removed_positions):
+                continue
+
             if cp.is_bundled:
                 try:
                     bundle = cp.addon_to.item.bundles.get(bundled_item=cp.item, bundled_variation=cp.variation)

src/tests/presale/test_cart.py

@@ -1023,6 +1023,18 @@ class CartTest(CartTestMixin, TestCase):
         self.assertIn('empty', doc.select('.alert-success')[0].text)
         self.assertFalse(CartPosition.objects.filter(cart_id=self.session_key, event=self.event).exists())
 
+    def test_remove_expired_voucher(self):
+        v = Voucher.objects.create(item=self.ticket, event=self.event, valid_until=now() - timedelta(days=1))
+        cp = CartPosition.objects.create(
+            event=self.event, cart_id=self.session_key, item=self.ticket,
+            price=23, expires=now() - timedelta(minutes=10), voucher=v
+        )
+        self.client.post('/%s/%s/cart/remove' % (self.orga.slug, self.event.slug), {
+            'id': cp.pk
+        }, follow=True)
+        objs = list(CartPosition.objects.filter(cart_id=self.session_key, event=self.event))
+        self.assertEqual(len(objs), 0)
+
     def test_voucher(self):
         v = Voucher.objects.create(item=self.ticket, event=self.event)
         self.client.post('/%s/%s/cart/add' % (self.orga.slug, self.event.slug), {