From 69879bdae06bdfbba1f3d2452d07b281a0e2c39d Mon Sep 17 00:00:00 2001
From: Raphael Michel <mail@raphaelmichel.de>
Date: Thu, 6 Aug 2020 09:28:35 +0200
Subject: [PATCH] Fix API bug: Do not delete SubEventItems on PATCH request

---
 src/pretix/api/serializers/event.py | 26 +++++++++++++-----------
 src/tests/api/test_subevents.py     | 31 +++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 12 deletions(-)

diff --git a/src/pretix/api/serializers/event.py b/src/pretix/api/serializers/event.py
index adee315bc..66950875c 100644
--- a/src/pretix/api/serializers/event.py
+++ b/src/pretix/api/serializers/event.py
@@ -459,27 +459,29 @@ class SubEventSerializer(I18nAwareModelSerializer):
 
     @transaction.atomic
     def update(self, instance, validated_data):
-        item_price_overrides_data = validated_data.pop('subeventitem_set') if 'subeventitem_set' in validated_data else {}
-        variation_price_overrides_data = validated_data.pop('subeventitemvariation_set') if 'subeventitemvariation_set' in validated_data else {}
+        item_price_overrides_data = validated_data.pop('subeventitem_set')
+        variation_price_overrides_data = validated_data.pop('subeventitemvariation_set')
         meta_data = validated_data.pop('meta_data', None)
         seat_category_mapping = validated_data.pop('seat_category_mapping', None)
         subevent = super().update(instance, validated_data)
 
-        existing_item_overrides = {item.item: item.id for item in SubEventItem.objects.filter(subevent=subevent)}
+        if item_price_overrides_data is not None:
+            existing_item_overrides = {item.item: item.id for item in SubEventItem.objects.filter(subevent=subevent)}
 
-        for item_price_override_data in item_price_overrides_data:
-            id = existing_item_overrides.pop(item_price_override_data['item'], None)
-            SubEventItem(id=id, subevent=subevent, **item_price_override_data).save()
+            for item_price_override_data in item_price_overrides_data:
+                id = existing_item_overrides.pop(item_price_override_data['item'], None)
+                SubEventItem(id=id, subevent=subevent, **item_price_override_data).save()
 
-        SubEventItem.objects.filter(id__in=existing_item_overrides.values()).delete()
+            SubEventItem.objects.filter(id__in=existing_item_overrides.values()).delete()
 
-        existing_variation_overrides = {item.variation: item.id for item in SubEventItemVariation.objects.filter(subevent=subevent)}
+        if variation_price_overrides_data is not None:
+            existing_variation_overrides = {item.variation: item.id for item in SubEventItemVariation.objects.filter(subevent=subevent)}
 
-        for variation_price_override_data in variation_price_overrides_data:
-            id = existing_variation_overrides.pop(variation_price_override_data['variation'], None)
-            SubEventItemVariation(id=id, subevent=subevent, **variation_price_override_data).save()
+            for variation_price_override_data in variation_price_overrides_data:
+                id = existing_variation_overrides.pop(variation_price_override_data['variation'], None)
+                SubEventItemVariation(id=id, subevent=subevent, **variation_price_override_data).save()
 
-        SubEventItemVariation.objects.filter(id__in=existing_variation_overrides.values()).delete()
+            SubEventItemVariation.objects.filter(id__in=existing_variation_overrides.values()).delete()
 
         # Meta data
         if meta_data is not None:
diff --git a/src/tests/api/test_subevents.py b/src/tests/api/test_subevents.py
index 31659aafb..5c9c16602 100644
--- a/src/tests/api/test_subevents.py
+++ b/src/tests/api/test_subevents.py
@@ -562,6 +562,37 @@ def test_subevent_update(token_client, organizer, event, subevent, item, item2,
     assert resp.content.decode() == '{"non_field_errors":["One or more variations do not belong to this event."]}'
 
 
+@pytest.mark.django_db
+def test_subevent_update_keep_subeventitems(token_client, organizer, event, subevent, item, item2):
+    resp = token_client.patch(
+        '/api/v1/organizers/{}/events/{}/subevents/{}/'.format(organizer.slug, event.slug, subevent.pk),
+        {
+            "item_price_overrides": [
+                {
+                    "item": item.pk,
+                    "price": "88.88",
+                    "disabled": True
+                }
+            ],
+        },
+        format='json'
+    )
+    assert resp.status_code == 200
+    with scopes_disabled():
+        assert event.subevents.get(id=subevent.id).item_overrides[item.pk].disabled
+
+    resp = token_client.patch(
+        '/api/v1/organizers/{}/events/{}/subevents/{}/'.format(organizer.slug, event.slug, subevent.pk),
+        {
+            "date_from": "2017-12-27T10:00:00Z",
+        },
+        format='json'
+    )
+    assert resp.status_code == 200
+    with scopes_disabled():
+        assert event.subevents.get(id=subevent.id).item_overrides[item.pk].disabled
+
+
 @pytest.mark.django_db
 def test_subevent_detail(token_client, organizer, event, subevent):
     res = dict(TEST_SUBEVENT_RES)