Add option to ignore quota when extending expired orders

src/pretix/control/forms/orders.py

@@ -15,6 +15,13 @@ from pretix.base.services.pricing import get_price
 
 
 class ExtendForm(I18nModelForm):
+    quota_ignore = forms.BooleanField(
+        label=_('Overbook quota'),
+        help_text=_('If you check this box, this operation will be performed even if it leads to an overbooked quota '
+                    'and you having sold more tickets than you planned!'),
+        required=False
+    )
+
     class Meta:
         model = Order
         fields = ['expires']
@@ -25,6 +32,11 @@ class ExtendForm(I18nModelForm):
             })
         }
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        if self.instance.status == Order.STATUS_PENDING or self.instance._is_still_available(now(), count_waitinglist=False) is True:
+            del self.fields['quota_ignore']
+
     def clean(self):
         data = super().clean()
         data['expires'] = data['expires'].replace(hour=23, minute=59, second=59)

src/pretix/control/views/orders.py

@@ -463,7 +463,7 @@ class OrderExtend(OrderView):
                 try:
                     with self.order.event.lock() as now_dt:
                         is_available = self.order._is_still_available(now_dt, count_waitinglist=False)
-                        if is_available is True:
+                        if is_available is True or self.form.cleaned_data.get('quota_ignore', False) is True:
                             self.form.save()
                             self.order.status = Order.STATUS_PENDING
                             self.order.save()
@@ -474,6 +474,7 @@ class OrderExtend(OrderView):
                             messages.success(self.request, _('The payment term has been changed.'))
                         else:
                             messages.error(self.request, is_available)
+                            return self._redirect_here()
                 except LockTimeoutException:
                     messages.error(self.request, _('We were not able to process the request completely as the '
                                                    'server was too busy.'))
@@ -487,6 +488,12 @@ class OrderExtend(OrderView):
             return self._redirect_back()
         return super().dispatch(request, *kwargs, **kwargs)
 
+    def _redirect_here(self):
+        return redirect('control:event.order.extend',
+                        event=self.request.event.slug,
+                        organizer=self.request.event.organizer.slug,
+                        code=self.order.code)
+
     def get(self, *args, **kwargs):
         return render(self.request, 'pretixcontrol/order/extend.html', {
             'order': self.order,