WordPress: Query custom post_status without registering it first

custom-post-status-query.php

<?php

add_action( 'pre_get_posts', '_custom_post_status_query' );

/**
 * As of WordPress API for custom post statuses is still in developement.
 * This method is a workaround to allow you to query posts by custom post 
 * status, without registering it with register_post_status();
 *
 * @param $query
 */
function _custom_post_status_query( $query ) {
    global $wp_post_statuses;
    
    $post_status = $query->get( 'post_status' );
    
    // Didn't really check if this is needed..
    if( ! $post_status )
        return;
    
    // This is the trick:
    // Add $post_status if it doesn't exists
    if( 'any' != $post_status && ! in_array( $post_status, array_keys( $wp_post_statuses ) ) ) {
        $wp_post_statuses[ $post_status ] = array(
    		'name' => $post_status,
    		'show_in_admin_status_list' => true,
    		'show_in_admin_all_list' => true,
    		'exclude_from_search' => true,
    		'public' => true,
    		'internal' => true,
    		'private' => true
        );
    }
}