Override default_actions() to remove actions that don't make sense for a null argument.
Overrides ArgumentPluginBase::default_actions
function default_actions($which = NULL) {
if ($which) {
if (in_array($which, array(
'ignore',
'not found',
'empty',
'default',
))) {
return parent::default_actions($which);
}
return;
}
$actions = parent::default_actions();
unset($actions['summary asc']);
unset($actions['summary desc']);
return $actions;
}