Include author matches in search results

gistfile1.aw

<?php
/**
 * Include posts from authors in the search results where
 * either their display name or user login matches the query string
 *
 * @author danielbachhuber
 */
add_filter( 'posts_search', 'db_filter_authors_search' );
function db_filter_authors_search( $posts_search ) {

	// Don't modify the query at all if we're not on the search template
	// or if the LIKE is empty
	if ( !is_search() || empty( $posts_search ) )
		return $posts_search;

	global $wpdb, $wp_query;
	// Get all of the users of the blog and see if the search query matches either
	// the display name or the user login
	$all_users = get_users();
	$matching_users = array();
	foreach( $all_users as $blog_user ) {
		if ( false !== stripos( $blog_user->display_name, $wp_query->query_vars['s'] ) || false !== stripos( $blog_user->user_login, $wp_query->query_vars['s'] ) )
			$matching_users[] = $blog_user->ID;
	}
	// Don't modify the query if there aren't any matching users
	if ( empty( $matching_users ) )
		return $posts_search;
	// Take a slightly different approach than core where we want all of the posts from these authors
	$posts_search = rtrim( $posts_search, ') ' );
	$posts_search .= ")) OR ( $wpdb->posts.post_author IN (" . implode( ',', array_map( 'absint', $matching_users ) ) . ")";
	return $posts_search . '))';
}