API: Fix creation of embedded variations with explicit sales channels

src/pretix/api/serializers/item.py

@@ -76,7 +76,9 @@ class InlineItemVariationSerializer(SalesChannelMigrationMixin, I18nAwareModelSe
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.fields['require_membership_types'].queryset = lazy(lambda: self.context['event'].organizer.membership_types.all(), QuerySet)
-        self.fields['limit_sales_channels'].child_relation.queryset = lazy(lambda: self.context['event'].organizer.sales_channels.all(), QuerySet)
+        self.fields['limit_sales_channels'].child_relation.queryset = (
+            self.context['event'].organizer.sales_channels() if 'event' in self.context else SalesChannel.objects.none()
+        )
 
     def validate_meta_data(self, value):
         for key in value['meta_data'].keys():
@@ -284,6 +286,7 @@ class ItemSerializer(SalesChannelMigrationMixin, I18nAwareModelSerializer):
             self.fields['require_membership_types'].queryset = self.context['event'].organizer.membership_types.all()
             self.fields['grant_membership_type'].queryset = self.context['event'].organizer.membership_types.all()
             self.fields['limit_sales_channels'].child_relation.queryset = self.context['event'].organizer.sales_channels.all()
+            self.fields['variations'].child.fields['limit_sales_channels'].child_relation.queryset = self.context['event'].organizer.sales_channels.all()
 
     def validate(self, data):
         data = super().validate(data)
@@ -371,10 +374,13 @@ class ItemSerializer(SalesChannelMigrationMixin, I18nAwareModelSerializer):
 
         for variation_data in variations_data:
             require_membership_types = variation_data.pop('require_membership_types', [])
+            limit_sales_channels = variation_data.pop('limit_sales_channels', [])
             var_meta_data = variation_data.pop('meta_data', {})
             v = ItemVariation.objects.create(item=item, **variation_data)
             if require_membership_types:
                 v.require_membership_types.add(*require_membership_types)
+            if limit_sales_channels:
+                v.limit_sales_channels.add(*limit_sales_channels)
 
             if var_meta_data is not None:
                 for key, value in var_meta_data.items():

src/pretix/api/serializers/order.py

@@ -585,7 +585,7 @@ class CheckinListOrderPositionSerializer(OrderPositionSerializer):
             self.fields['item'] = ItemSerializer(read_only=True, context=self.context)
 
         if 'variation' in self.context['expand']:
-            self.fields['variation'] = InlineItemVariationSerializer(read_only=True)
+            self.fields['variation'] = InlineItemVariationSerializer(read_only=True, context=self.context)
 
         if 'answers.question' in self.context['expand']:
             self.fields['answers'].child.fields['question'] = QuestionSerializer(read_only=True)

src/tests/api/test_items.py

@@ -590,7 +590,28 @@ def test_item_create_with_variation(token_client, organizer, event, item, catego
                     "meta_data": {
                         "day": "Wednesday",
                     },
-                }
+                },
+                {
+                    "value": {
+                        "de": "web",
+                        "en": "web"
+                    },
+                    "active": True,
+                    "require_approval": True,
+                    "checkin_attention": False,
+                    "checkin_text": None,
+                    "require_membership": False,
+                    "require_membership_hidden": False,
+                    "require_membership_types": [],
+                    "description": None,
+                    "position": 0,
+                    "default_price": None,
+                    "sales_channels": ["web"],
+                    "price": "23.00",
+                    "meta_data": {
+                        "day": "Wednesday",
+                    },
+                },
             ]
         },
         format='json'
@@ -604,6 +625,8 @@ def test_item_create_with_variation(token_client, organizer, event, item, catego
         assert new_item.variations.first().all_sales_channels is True
         assert not new_item.variations.first().limit_sales_channels.exists()
         assert new_item.variations.first().meta_data == {"day": "Wednesday"}
+        assert new_item.variations.last().all_sales_channels is False
+        assert new_item.variations.last().limit_sales_channels.exists()
 
 
 @pytest.mark.django_db