give a hint when a page is missing (#27031)

combo/public/views.py

@@ -423,7 +423,7 @@ def page(request):
         redirect = Redirect.objects.filter(old_url=url).last()
         if redirect:
             return HttpResponseRedirect(redirect.page.get_online_url())
-        raise Http404()
+        raise Http404("combo: can't find the requested page, you might need to create it.")
 
     return publish_page(request, page)
 

tests/test_public.py

@@ -276,6 +276,11 @@ def test_404(app):
     resp = app.get('/foobar/', status=404)
     assert 'Custom 404 Text' in resp.text
 
+    with override_settings(DEBUG=True):
+        # check error page provides an hint when debugging
+        resp = app.get('/foobar/', status=404)
+        assert "can't find the requested page" in resp.text
+
 def test_style_demo(app, admin_user):
     TextCell.objects.all().delete()
     Page.objects.all().delete()