Get parse_query filter to return slug instead of id

taxonomy & term won’t be set (in this case), since query vars are mapped from GET/POST.

In other words, $qv['large_feature'] = 291 (see wp_edit_posts_query() and WP_Query::get_posts() for the big picture).

add_filter( 'parse_query','convert_large_feature_id_to_taxonomy_term_in_query' );

function convert_large_feature_id_to_taxonomy_term_in_query( $query ) {
    global $pagenow;

    $qv =& $query->query_vars;

    if (
        $pagenow == 'edit.php' &&
        isset( $qv['large_feature'] ) &&
        ctype_digit( $qv['large_feature'] ) // stricter than is_numeric()
    ) {
        if ( $term = get_term_by( 'id', $qv['large_feature'], 'large_feature' ) )
            $qv['large_feature'] = $term->slug;
    }
}