Hmph… okay… I’ve noticed that /plugins/bbpress/includes/search/template.php is actually responsible for that feature:
function bbp_has_search_results( $args = '' ) {
global $wp_rewrite;
/** Defaults **************************************************************/
$default_post_type = array( bbp_get_forum_post_type(), bbp_get_topic_post_type(), bbp_get_reply_post_type() );
// Default query args
$default = array(
'post_type' => $default_post_type, // Forums, topics, and replies
'posts_per_page' => bbp_get_replies_per_page(), // This many
'paged' => bbp_get_paged(), // On this page
'orderby' => 'date', // Sorted by date
'order' => 'DESC', // Most recent first
'ignore_sticky_posts' => true, // Stickies not supported
's' => bbp_get_search_terms(), // This is a search
);
So, changing ‘post_type’ => $default_post_type to ‘post_type’ => bbp_get_topic_post_type() works. However, it’s not clearly the best practice to modify the plugin directly anyother way to override this?