Relevanssi updated Polylang function

polylang.php

<?php

function relevanssi_polylang_where_include_terms( $where ) {
	global $wpdb;

	$current_language = substr( get_locale(), 0, 2 );
	if ( function_exists( 'pll_current_language' ) ) {
		$current_language = pll_current_language();
	}
	$languages   = get_terms( array( 'taxonomy' => 'language' ) );
	$language_id = 0;
	foreach ( $languages as $language ) {
		if (
			! is_wp_error( $language ) &&
			$language instanceof WP_Term &&
			$language->slug === $current_language
			) {
			$language_id = intval( $language->term_id );
			break;
		}
	}
	// Language ID should now have current language ID.
	if ( 0 !== $language_id ) {
		// Do a simple search-and-replace to modify the query.
		$where = preg_replace( '/\s+/', ' ', $where );
		$where = preg_replace( '/\(\s/', '(', $where );
		$where = str_replace(
			"AND relevanssi.doc IN (SELECT DISTINCT(tr.object_id) FROM {$wpdb->prefix}term_relationships AS tr WHERE tr.term_taxonomy_id IN ($language_id))",
			"AND (relevanssi.doc IN ( SELECT DISTINCT(tr.object_id) FROM {$wpdb->prefix}term_relationships AS tr WHERE tr.term_taxonomy_id IN ($language_id)) OR (relevanssi.doc = -1))",
			$where
		);
	}
	return $where;
}