Fix price calculation of included add-ons in expired carts

src/pretix/base/services/cart.py

@@ -453,12 +453,15 @@ class CartManager:
             if cp.is_bundled:
                 bundle = cp.addon_to.item.bundles.filter(bundled_item=cp.item, bundled_variation=cp.variation).first()
                 if bundle:
-                    listed_price = bundle.designated_price or 0
+                    listed_price = bundle.designated_price or Decimal('0.00')
                 else:
                     listed_price = cp.price
                 price_after_voucher = listed_price
             else:
-                listed_price = get_listed_price(cp.item, cp.variation, cp.subevent)
+                if cp.addon_to_id and is_included_for_free(cp.item, cp.addon_to):
+                    listed_price = Decimal('0.00')
+                else:
+                    listed_price = get_listed_price(cp.item, cp.variation, cp.subevent)
                 if cp.voucher:
                     price_after_voucher = cp.voucher.calculate_price(listed_price)
                 else:

src/tests/presale/test_cart.py

@@ -2380,6 +2380,25 @@ class CartAddonTest(CartTestMixin, TestCase):
         assert cp2.item == self.workshop1
         assert cp2.price == 0
 
+    @classscope(attr='orga')
+    def test_extend_included_addon(self):
+        self.addon1.price_included = True
+        self.addon1.save()
+        cp1 = CartPosition.objects.create(
+            expires=now() - timedelta(minutes=10), item=self.ticket, price=Decimal('23.00'),
+            event=self.event, cart_id=self.session_key
+        )
+        cp2 = CartPosition.objects.create(
+            expires=now() - timedelta(minutes=10), item=self.workshop1, price=Decimal('0.00'),
+            event=self.event, cart_id=self.session_key, addon_to=cp1
+        )
+        self.cm.extend_expired_positions()
+        self.cm.commit()
+        cp2.refresh_from_db()
+        assert cp2.expires > now()
+        assert cp2.item == self.workshop1
+        assert cp2.price == 0
+
     @classscope(attr='orga')
     def test_cart_addon_remove_parent(self):
         self.addon1.price_included = True