add: handle protected error in base delete view

base/views.py

@@ -4,11 +4,14 @@
 # standard library
 
 # django
+from django.db.models import ProtectedError
 from django.conf import settings
+from django.contrib import messages
 from django.contrib.admin.views.decorators import staff_member_required
 from django.contrib.auth.decorators import login_required
 from django.contrib.auth.mixins import AccessMixin
 from django.core.exceptions import ImproperlyConfigured
+from django.http import HttpResponseRedirect
 from django.shortcuts import get_object_or_404
 from django.shortcuts import render
 from django.urls import reverse
@@ -308,6 +311,24 @@ def get_success_url(self):
         model_name = self.model.__name__.lower()
         return reverse('{}_list'.format(model_name))
 
+    def post(self, request, *args, **kwargs):
+        try:
+            return self.delete(request, *args, **kwargs)
+        except ProtectedError as error:
+            return self.handle_protected_error(request, error)
+
+    def handle_protected_error(self, request, error):
+        """
+        Overwrite this method if you want to change the error message or
+        redirect to a different view.
+        """
+        messages.add_message(
+            request,
+            messages.ERROR,
+            _("This object cannot be deleted."),
+        )
+        return HttpResponseRedirect(self.object.get_absolute_url())
+
 
 class BaseRedirectView(LoginPermissionRequiredMixin, RedirectView):
     login_required = True