Allow quotas to "close" when once full (#1344)

* Model

* Some UI

* API and logging

* Permission check

* Add tests

* Move option around

src/pretix/base/migrations/0128_auto_20190715_1510.py

@@ -0,0 +1,26 @@
+# Generated by Django 2.2.1 on 2019-07-15 15:10
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+import pretix.base.models.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0127_auto_20190711_0705'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='quota',
+            name='close_when_sold_out',
+            field=models.BooleanField(default=False),
+        ),
+        migrations.AddField(
+            model_name='quota',
+            name='closed',
+            field=models.BooleanField(default=False),
+        ),
+    ]

src/pretix/base/models/event.py

@@ -518,6 +518,11 @@ class Event(EventMixin, LoggedModel):
             vars = list(q.variations.all())
             q.pk = None
             q.event = self
+            q.cached_availability_state = None
+            q.cached_availability_number = None
+            q.cached_availability_paid_orders = None
+            q.cached_availability_time = None
+            q.closed = False
             q.save()
             for i in items:
                 if i.pk in item_map:

src/pretix/base/models/items.py

@@ -1269,6 +1269,15 @@ class Quota(LoggedModel):
     cached_availability_paid_orders = models.PositiveIntegerField(null=True, blank=True)
     cached_availability_time = models.DateTimeField(null=True, blank=True)
 
+    close_when_sold_out = models.BooleanField(
+        verbose_name=_('Close this quota permanently once it is sold out'),
+        help_text=_('If you enable this, when the quota is sold out once, no more tickets will be sold, '
+                    'even if tickets become available again through cancellations or expiring orders. Of course, '
+                    'you can always re-open it manually.'),
+        default=False
+    )
+    closed = models.BooleanField(default=False)
+
     objects = ScopedManager(organizer='event__organizer')
 
     class Meta:
@@ -1334,6 +1343,11 @@ class Quota(LoggedModel):
                                                   count_waitinglist=count_waitinglist):
             res = resp
 
+        if res[0] <= Quota.AVAILABILITY_ORDERED and self.close_when_sold_out and not self.closed:
+            self.closed = True
+            self.save(update_fields=['closed'])
+            self.log_action('pretix.event.quota.closed')
+
         self.event.cache.delete('item_quota_cache')
         rewrite_cache = count_waitinglist and (
             not self.cache_is_hot(now_dt) or res[0] > self.cached_availability_state
@@ -1358,8 +1372,11 @@ class Quota(LoggedModel):
             _cache['_count_waitinglist'] = count_waitinglist
         return res
 
-    def _availability(self, now_dt: datetime=None, count_waitinglist=True):
+    def _availability(self, now_dt: datetime=None, count_waitinglist=True, ignore_closed=False):
         now_dt = now_dt or now()
+        if self.closed and not ignore_closed:
+            return Quota.AVAILABILITY_ORDERED, 0
+
         size_left = self.size
         if size_left is None:
             return Quota.AVAILABILITY_OK, None