API: Fix crash expanding variations

src/pretix/api/serializers/item.py

@@ -77,7 +77,7 @@ class InlineItemVariationSerializer(SalesChannelMigrationMixin, I18nAwareModelSe
         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 = (
-            self.context['event'].organizer.sales_channels() if 'event' in self.context else SalesChannel.objects.none()
+            self.context['event'].organizer.sales_channels.all() if 'event' in self.context else SalesChannel.objects.none()
         )
 
     def validate_meta_data(self, value):

src/pretix/api/views/checkin.py

@@ -406,7 +406,7 @@ def _checkin_list_position_queryset(checkinlists, ignore_status=False, ignore_pr
                                  'item__variations').select_related('item__tax_rule')
 
     if expand and 'variation' in expand:
-        qs = qs.prefetch_related('variation')
+        qs = qs.prefetch_related('variation', 'variation__meta_values')
 
     return qs
 

src/tests/api/test_checkin.py

@@ -1381,3 +1381,18 @@ def test_checkin_pdf_data_requires_permission(token_client, event, team, organiz
         organizer.slug, event.slug, clist_all.pk
     ))
     assert not resp.data['results'][0].get('pdf_data')
+
+
+@pytest.mark.django_db
+def test_expand(token_client, organizer, event, clist, clist_all, item, other_item, order, django_assert_max_num_queries):
+    with scopes_disabled():
+        op = order.positions.first()
+        var1 = item.variations.create(value="XS")
+        op.variation = var1
+        op.save()
+
+    resp = token_client.get('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/?search=z3fsn8jyu&expand=variation'.format(
+        organizer.slug, event.slug, clist_all.pk
+    ))
+    assert resp.status_code == 200
+    assert 'value' in resp.data['results'][0]['variation']