Add custom post types to search results in WordPress.

gistfile1.php

<?php
add_filter( 'pre_get_posts', 'tgm_io_cpt_search' );
/**
 * This function modifies the main WordPress query to include an array of 
 * post types instead of the default 'post' post type.
 *
 * @param object $query  The original query.
 * @return object $query The amended query.
 */
function tgm_io_cpt_search( $query ) {
	
    if ( $query->is_search ) {
	$query->set( 'post_type', array( 'post', 'movies', 'products', 'portfolio' ) );
    }
    
    return $query;
    
}

Just found this, thank you a lot !

Be carefuel to use this code example!
It makes VERY FRUSTRAITING BUG on admin page. I've spent 2 days to find it.
When you are on admin page this function doesn't allow you to filter custom post types and woocommerce products on categories, dates etc..
Better change 12th line of code in such way:
12. if ( $query->is_search && !is_admin() ) { .....
Just check if you are not on admin dashboard...

Thanks!