Ticket #19572: patch.diff

<?php

$WP_POST_STACK = array();

function switch_to_post($post_id) {
        global $WP_POST_STACK, $post;

        // Initialize the stack with very first $post->ID
        if ( !count( $WP_POST_STACK ) ) {
                $WP_POST_STACK[] = $post->ID;
        }

        // Stick our new post_id onto the end
        $WP_POST_STACK[] = $post_id;
        $post = get_post( $post_id );
        setup_postdata( $post );
        do_action( 'switch_to_post', $post_id );

        return true;
}

function restore_post() {
        global $WP_POST_STACK, $post;

        // If we don't have anything to knock off, just return
        if ( count( $WP_POST_STACK ) ) {
                // Remove the current post_id off the stack
                $removed_post_id = array_pop( $WP_POST_STACK );
        
                // Get last value of the array but leave it on the array
                if ( $post_id = end( $WP_POST_STACK ) ) {
                        $post = get_post( $post_id );
                        setup_postdata( $post );
                        do_action( 'restore_post', $post_id, $removed_post_id );
                        return true;
                }
        }
        return false;
}