After fumbling around with this for a bit, I realized I needed this to work with custom taxonomies, not just regular categories. I unfortunately couldn’t use “all” of what either the solution I found or Tom did, so I ended up writing my own. As long as you specify a taxonomy
arg, you should be all set:
function add_category_ancestor_class($args) {
$list_args = $args;
$list_args['echo'] = '0';
$catlist = wp_list_categories($list_args);
if ( is_tax($list_args['taxonomy']) ) {
global $wp_query;
$term = $wp_query->get_queried_object();
$term_object = get_term_by('id', $term->term_id, $list_args['taxonomy']);
$current_term = $term->term_id;
$ancestors = get_ancestors($current_term, $list_args['taxonomy']);
// how many levels more than two set hierarchical ancestor?
// count from 1 array from 0 : 1:0=Current 2:1=Parent >2:1 all Ancestors
if( count($ancestors) >= 2){
$max = count($ancestors) - 1; //Array elements zero based = count - 1
$extra_class="current-cat-ancestor";
for ( $counter = 1; $counter <= $max; $counter ++) {
$cat_ancestor_class="cat-item cat-item-". $ancestors[$counter];
$amended_class = $cat_ancestor_class . ' ' . $extra_class;
$catlist = str_replace($cat_ancestor_class, $amended_class, $catlist );
}
}
}
$menu = str_replace( array( "\r", "\n", "\t" ), '', $catlist );
return $menu;
}
Really hoping this gets into WordPress at some point though. Thanks!