Refs #105 -- Variation support for vouchers

src/pretix/base/models/items.py

@@ -493,17 +493,18 @@ class Quota(LoggedModel):
     def count_blocking_vouchers(self) -> int:
         from pretix.base.models import Voucher
         return Voucher.objects.filter(
-            item__quotas__in=[self],
-            block_quota=True,
-            redeemed=False
+            Q(item__quotas__in=[self]) &
+            Q(block_quota=True) &
+            Q(redeemed=False) &
+            self._position_lookup
         ).count()
 
     def count_in_cart(self) -> int:
         from pretix.base.models import CartPosition
 
         return CartPosition.objects.filter(
-            Q(expires__gte=now())
-            & self._position_lookup
+            Q(expires__gte=now()) &
+            self._position_lookup
         ).count()
 
     def count_orders(self) -> dict:

src/pretix/base/models/vouchers.py

@@ -5,7 +5,7 @@ from django.utils.translation import ugettext_lazy as _
 
 from .base import LoggedModel
 from .event import Event
-from .items import Item
+from .items import Item, ItemVariation
 from .orders import CartPosition, OrderPosition
 
 
@@ -63,6 +63,14 @@ class Voucher(LoggedModel):
             "This product is added to the user's cart if the voucher is redeemed."
         )
     )
+    variation = models.ForeignKey(
+        ItemVariation, related_name='vouchers',
+        null=True, blank=True,
+        verbose_name=_("Product variation"),
+        help_text=_(
+            "This variation of the product select above is being used."
+        )
+    )
 
     class Meta:
         verbose_name = _("Voucher")