id summary reporter owner description type status component version severity resolution keywords cc stage has_patch needs_docs needs_tests needs_better_patch easy ui_ux 32260 handler500 as a Class-based view raises SystemCheckError Daniyal Abbasi Daniyal Abbasi "Setting handler500 as a Class-Based view raises the following error which running checks. {{{ $ python manage.py check SystemCheckError: System check identified some issues: ERRORS: ?: (urls.E007) The custom handler500 view 'path.to.my.MyView' does not take the correct number of arguments (request). }}} In my root urls.py, I have the following configuration, {{{ handler404 = MyView.as_view() handler500 = MyView.as_view() }}} I believe this is due to the function `_check_custom_error_handlers` in `django/urls/resolver.py`. The signature variable in this function is expected to match (request, exception) for all handlers except for handler500 which is expected to have only (request). A positional argument, template_name is also present. While using class based views, we get two positional arguments (self, request) and then it recieves *args and * *kwargs. The check is permitting other handlers as the number of arguments coincidentally match. I suggest a fix in the `_check_custom_error_handlers` which first checks if the handler* are function based or class based, and then it preceed the check with the appropriate number of arguments. " Cleanup/optimization closed Core (System checks) dev Normal fixed Ready for checkin 1 0 0 0 0 0