Ticket #3753: template-invalid-varname.diff

django/template/__init__.py

@@ -566 +566 @@
                 obj = None
             else:
                 if settings.TEMPLATE_STRING_IF_INVALID:
+                    if settings.TEMPLATE_STRING_IF_INVALID.count('%s') == 1:
+                        return settings.TEMPLATE_STRING_IF_INVALID % self.var
                     return settings.TEMPLATE_STRING_IF_INVALID
                 else:
                     obj = settings.TEMPLATE_STRING_IF_INVALID