Fix waiting list availability calculation if WL vouchers have seats (Z#23226856)

src/pretix/base/models/waitinglist.py

@@ -181,10 +181,11 @@ class WaitingListEntry(LoggedModel):
                 block_quota=True,
                 item_id=self.item_id,
                 subevent_id=self.subevent_id,
-                waitinglistentries__isnull=False
+                waitinglistentries__isnull=False,
+                seat__isnull=True
             ).aggregate(free=Sum(F('max_usages') - F('redeemed')))['free'] or 0
             free_seats = num_free_seats_for_product - num_valid_vouchers_for_product
-            if not free_seats:
+            if free_seats < 1:
                 raise WaitingListException(_('No seat with this product is currently available.'))
 
         if '@' not in self.email:

src/pretix/control/views/waitinglist.py

@@ -280,11 +280,12 @@ class WaitingListView(EventPermissionRequiredMixin, WaitingListQuerySetMixin, Pa
                         block_quota=True,
                         item_id=wle.item_id,
                         subevent=wle.subevent_id,
-                        waitinglistentries__isnull=False
+                        waitinglistentries__isnull=False,
+                        seat__isnull=True
                     ).aggregate(free=Sum(F('max_usages') - F('redeemed')))['free'] or 0
                     free_seats = num_free_seats_for_product - num_valid_vouchers_for_product
                     wle.availability = (
-                        Quota.AVAILABILITY_GONE if free_seats == 0 else wle.availability[0],
+                        Quota.AVAILABILITY_GONE if free_seats < 1 else wle.availability[0],
                         min(free_seats, wle.availability[1]) if wle.availability[1] is not None else free_seats,
                     )
 

src/tests/control/test_waitinglist.py

@@ -29,6 +29,8 @@ from pretix.base.models import (
     Event, Item, ItemVariation, Organizer, Quota, Team, User, Voucher,
     WaitingListEntry,
 )
+from pretix.base.models.seating import Seat, SeatingPlan
+from pretix.base.models.waitinglist import WaitingListException
 from pretix.control.views.dashboards import waitinglist_widgets
 
 
@@ -55,11 +57,11 @@ def env():
     WaitingListEntry.objects.create(
         event=event, item=item1, email='success@example.org', voucher=v
     )
-    v = Voucher.objects.create(item=item1, event=event, block_quota=True, redeemed=0, valid_until=now() - timedelta(days=5))
+    v = Voucher.objects.create(item=item2, event=event, block_quota=True, redeemed=0, valid_until=now() - timedelta(days=5))
     WaitingListEntry.objects.create(
         event=event, item=item2, email='expired@example.org', voucher=v
     )
-    v = Voucher.objects.create(item=item1, event=event, block_quota=True, redeemed=0, valid_until=now() + timedelta(days=5))
+    v = Voucher.objects.create(item=item2, event=event, block_quota=True, redeemed=0, valid_until=now() + timedelta(days=5))
     WaitingListEntry.objects.create(
         event=event, item=item2, email='valid@example.org', voucher=v
     )
@@ -345,5 +347,75 @@ def test_dashboard(client, env):
         quota.items.add(env['item1'])
         w = waitinglist_widgets(env['event'])
 
-    assert '1' in w[0]['content']
+    assert '2' in w[0]['content']
     assert '5' in w[1]['content']
+
+
+@pytest.mark.django_db
+def test_waitinglist_seat_calc(client, env):
+    item = env['item1']
+    event = env['event']
+    wle = env['wle']
+
+    SeatingPlan.objects.create(
+        name="Plan", organizer=event.organizer, layout="{}"
+    )
+    event.seat_category_mappings.create(
+        layout_category='Stalls', product=item
+    )
+    for i in range(2):
+        event.seats.create(seat_number=f"A{i}", product=item, seat_guid=f"A{i}")
+
+    quota = Quota.objects.create(event=event, size=10)
+    quota.items.add(item)
+
+    client.login(email='dummy@dummy.dummy', password='dummy')
+
+    # Calculated availability should not be more than number of available seats
+    response = client.get('/control/event/dummy/dummy/waitinglist/')
+    assert len(response.context['entries']) == 5
+    for entry in response.context['entries']:
+        assert entry.availability == (Quota.AVAILABILITY_OK, 2)
+
+    # Sending out a voucher reduces availability by 1
+    with scopes_disabled():
+        wle.send_voucher()
+
+    voucher = wle.voucher
+    assert voucher
+
+    response = client.get('/control/event/dummy/dummy/waitinglist/')
+    assert len(response.context['entries']) == 4
+    for entry in response.context['entries']:
+        assert entry.availability == (Quota.AVAILABILITY_OK, 1)
+
+    # Assigning a seat to a voucher does not decrease availability further
+    with scopes_disabled():
+        voucher.seat = Seat.objects.get(seat_guid="A0")
+        voucher.save()
+
+    response = client.get('/control/event/dummy/dummy/waitinglist/')
+    assert len(response.context['entries']) == 4
+    for entry in response.context['entries']:
+        assert entry.availability == (Quota.AVAILABILITY_OK, 1)
+
+    with scopes_disabled():
+        wle2 = WaitingListEntry.objects.filter(item=item, voucher__isnull=True).first()
+        wle2.send_voucher()
+
+    # Overbooking is handled correctly
+    # Regression test for calculation that used `not free_seats` instead of `free_seats < 1`
+    with scopes_disabled():
+        # Block seat
+        seat = Seat.objects.get(seat_guid="A1")
+        seat.blocked = True
+        seat.save()
+
+    response = client.get('/control/event/dummy/dummy/waitinglist/')
+    assert len(response.context['entries']) == 3
+    for entry in response.context['entries']:
+        assert entry.availability == (Quota.AVAILABILITY_GONE, -1)
+
+    with scopes_disabled(), pytest.raises(WaitingListException):
+        wle3 = WaitingListEntry.objects.filter(item=item, voucher__isnull=True).first()
+        wle3.send_voucher()