Allow to copy vouchers

src/pretix/control/templates/pretixcontrol/vouchers/index.html

@@ -138,6 +138,10 @@
                                 <td>{{ v.subevent.name }} – {{ v.subevent.get_date_range_display }}</td>
                             {% endif %}
                             <td class="text-right">
+                                <a href="{% url "control:event.vouchers.bulk" organizer=request.event.organizer.slug event=request.event.slug %}?copy_from={{ v.id }}"
+                                   class="btn btn-sm btn-default" title="{% trans "Use as a template for new vouchers" %}" data-toggle="tooltip">
+                                    <span class="fa fa-copy"></span>
+                                </a>
                                 <a href="{% url "control:event.voucher.delete" organizer=request.event.organizer.slug event=request.event.slug voucher=v.id %}" class="btn btn-danger btn-sm"><i class="fa fa-trash"></i></a>
                             </td>
                         </tr>

src/pretix/control/views/vouchers.py

@@ -24,6 +24,7 @@ from pretix.control.forms.vouchers import VoucherBulkForm, VoucherForm
 from pretix.control.permissions import EventPermissionRequiredMixin
 from pretix.control.signals import voucher_form_class
 from pretix.control.views import PaginationMixin
+from pretix.helpers.models import modelcopy
 
 
 class VoucherList(PaginationMixin, EventPermissionRequiredMixin, ListView):
@@ -279,9 +280,23 @@ class VoucherBulkCreate(EventPermissionRequiredMixin, CreateView):
             'event': self.request.event.slug,
         })
 
+    @cached_property
+    def copy_from(self):
+        if self.request.GET.get("copy_from") and not getattr(self, 'object', None):
+            try:
+                return self.request.event.vouchers.get(pk=self.request.GET.get("copy_from"))
+            except Voucher.DoesNotExist:
+                pass
+
     def get_form_kwargs(self):
         kwargs = super().get_form_kwargs()
-        kwargs['instance'] = Voucher(event=self.request.event)
+
+        if self.copy_from:
+            i = modelcopy(self.copy_from)
+            i.pk = None
+            kwargs['instance'] = i
+        else:
+            kwargs['instance'] = Voucher(event=self.request.event)
         return kwargs
 
     @transaction.atomic