Enable BuddyPress Docs search to match based on attachment filenames

bp-docs-attachment-search.php

<?php

/**
 * This is not needed for BP Docs 2.1+. See https://github.com/boonebgorges/buddypress-docs/issues/592
 */

add_filter( 'bp_docs_pre_query_args', function( $args, BP_Docs_Query $query ) {
	// For attachments, search separately and then append to WP's default search handling.
	if ( bp_docs_enable_attachments() ) {
		add_filter( 'posts_clauses', '_filter_query_attachment_filenames' );
		$attachment_posts = get_posts( array(
			'post_type' => 'attachment',
			'post_status' => 'inherit',
			's' => $query->query_args['search_terms'],
		) );

		if ( $attachment_posts ) {
			$GLOBALS['bp_docs_search_attachment_parents'] = wp_list_pluck( $attachment_posts, 'post_parent' );
			add_filter( 'posts_search', 'bbg_attachment_filename_search_filter' );
		}
	}

	return $args;
}, 10, 2 );

/**
 * Filters post search to include Docs with attachments whose filename matches search term.
 *
 * @param string $search Search string, as generated by WP_Query.
 * @return string Modified SQL clause.
 */
function bbg_attachment_filename_search_filter( $search ) {
	global $wpdb, $bp_docs_search_attachment_parents;

	remove_filter( 'posts_clauses', 'bbg_attachment_filename_search_filter' );

	if ( ! $search || empty( $bp_docs_search_attachment_parents ) ) {
		return $search;
	}

	$raw_search = preg_replace( '/^\s*AND/', '', $search );
	$parent_ids = implode( ',', array_map( 'intval', $bp_docs_search_attachment_parents ) );
	$search = " AND ( $wpdb->posts.ID IN ({$parent_ids}) OR $raw_search )";

	return $search;
}