Add error messages to forms

src/pretix/control/views/item.py

@@ -156,6 +156,10 @@ class CategoryUpdate(EventPermissionRequiredMixin, UpdateView):
             'event': self.request.event.slug,
         })
 
+    def form_invalid(self, form):
+        messages.error(self.request, _('We could not save your changes. See below for details.'))
+        return super().form_invalid(form)
+
 
 class CategoryCreate(EventPermissionRequiredMixin, CreateView):
     model = ItemCategory
@@ -178,6 +182,10 @@ class CategoryCreate(EventPermissionRequiredMixin, CreateView):
         form.instance.log_action('pretix.event.category.added', data=dict(form.cleaned_data), user=self.request.user)
         return ret
 
+    def form_invalid(self, form):
+        messages.error(self.request, _('We could not save your changes. See below for details.'))
+        return super().form_invalid(form)
+
 
 class CategoryList(ListView):
     model = ItemCategory
@@ -479,6 +487,10 @@ class QuestionUpdate(EventPermissionRequiredMixin, QuestionMixin, UpdateView):
             'event': self.request.event.slug,
         })
 
+    def form_invalid(self, form):
+        messages.error(self.request, _('We could not save your changes. See below for details.'))
+        return super().form_invalid(form)
+
 
 class QuestionCreate(EventPermissionRequiredMixin, QuestionMixin, CreateView):
     model = Question
@@ -501,6 +513,10 @@ class QuestionCreate(EventPermissionRequiredMixin, QuestionMixin, CreateView):
     def get_object(self, **kwargs):
         return None
 
+    def form_invalid(self, form):
+        messages.error(self.request, _('We could not save your changes. See below for details.'))
+        return super().form_invalid(form)
+
     @transaction.atomic
     def form_valid(self, form):
         if form.cleaned_data.get('type') in ('M', 'C'):
@@ -592,6 +608,10 @@ class QuotaCreate(EventPermissionRequiredMixin, QuotaEditorMixin, CreateView):
         form.instance.log_action('pretix.event.quota.added', user=self.request.user, data=dict(form.cleaned_data))
         return ret
 
+    def form_invalid(self, form):
+        messages.error(self.request, _('We could not save your changes. See below for details.'))
+        return super().form_invalid(form)
+
 
 class QuotaView(ChartContainingView, DetailView):
     model = Quota
@@ -699,6 +719,10 @@ class QuotaUpdate(EventPermissionRequiredMixin, QuotaEditorMixin, UpdateView):
             'quota': self.object.pk
         })
 
+    def form_invalid(self, form):
+        messages.error(self.request, _('We could not save your changes. See below for details.'))
+        return super().form_invalid(form)
+
 
 class QuotaDelete(EventPermissionRequiredMixin, DeleteView):
     model = Quota
@@ -794,6 +818,10 @@ class ItemCreate(EventPermissionRequiredMixin, CreateView):
         kwargs.update({'instance': newinst})
         return kwargs
 
+    def form_invalid(self, form):
+        messages.error(self.request, _('We could not save your changes. See below for details.'))
+        return super().form_invalid(form)
+
 
 class ItemUpdateGeneral(ItemDetailMixin, EventPermissionRequiredMixin, UpdateView):
     form_class = ItemUpdateForm
@@ -822,6 +850,10 @@ class ItemUpdateGeneral(ItemDetailMixin, EventPermissionRequiredMixin, UpdateVie
             CachedTicket.objects.filter(order_position__item=self.item).delete()
         return super().form_valid(form)
 
+    def form_invalid(self, form):
+        messages.error(self.request, _('We could not save your changes. See below for details.'))
+        return super().form_invalid(form)
+
 
 class ItemVariations(ItemDetailMixin, EventPermissionRequiredMixin, TemplateView):
     permission = 'can_change_items'
@@ -878,6 +910,7 @@ class ItemVariations(ItemDetailMixin, EventPermissionRequiredMixin, TemplateView
 
                 messages.success(self.request, _('Your changes have been saved.'))
                 return redirect(self.get_success_url())
+        messages.error(self.request, _('We could not save your changes. See below for details.'))
         return self.get(request, *args, **kwargs)
 
     def get_success_url(self) -> str: