Searching for a category returns nothing if category is empty

Question

In the navigation menu creation page, when you are trying to add a category to the menu, if the category is empty, it won't show up in the search results. However, if the category itself is empty but has a child that is not empty, it will still be shown.

I have a blog with over 500 categories, and I'm trying to add some of them to the menu but they have no posts yet. Navigating through category list is going to take time, and is also frustrating.

Now I've tracked down the issue to /wp-admin/includes/nav-menu.php, ( starting at line 588 ) but can't find a filter or hook to do so.

This line (109) seems to be responsible for doing the search:

$terms = get_terms( $matches[2], array(
    'name__like' => $query,
    'number' => 10,
));

According to the documentations, this function accepts an argument for showing empty terms 'hide_empty' => false, but I can't see such option in this part of core's code. I've added this option to the core (temporarily) to see if it solves the issue, and it does.

Can this be a bug? And is it possible to enable the search to return the result no matter the category has a post or not?

Answer 1

You can modify this behaviour by adding a custom filter to your functions.php or as a plugin:

add_filter('get_terms_args', 'wodruoso_terms_args', 10, 1); 
function wodruoso_terms_args($args) {
    /* note: I am checking here that we are in WP Admin area and that it's
    *  search by category name to minimize impact on other areas
    */
    if(is_admin() && isset($args["name__like"]) && !empty($args["name__like"])) {
        $args["hide_empty"] = false;
    }
    return $args;
}

Answer 2

The posted answer does temporarily resolve the issue, but only while doing a quick search using AJAX.

I've created and uploaded a patch on trac here. This patch fully resolves the issue, while allowing the user to exclude/include empty taxonomies from search results.

Feedbacks from anyone is appreciated.