publish periodical post

function mag_check_for_new_issue_on_publish( $post_id ){

// check that this is a real publish and not an update
if( ( $_POST['post_status'] == 'publish' ) && ( $_POST['original_post_status'] != 'publish' ) ) {
// is the post in the master category?
if ( in_category( get_option( 'mag_master_category' ) , $post_id ) ) {
// get the issue and assign this to global option current_issue
$terms = get_the_terms ( $post_id , 'issue' );
if ($terms) {
update_option ( 'mag_current_issue' , $terms[0]->slug );
}
// publish all posts that are in the same issue
$args = array(
'posts_per_page' => -1,
'post_status' => 'pending',
'tax_query' => array(
array(
'taxonomy' => 'issue',
'field' => 'slug',
'terms' => $terms[0]->slug,
)
)
);
remove_action( 'publish_post' , 'mag_check_for_new_issue_on_publish' );

// get list of posts
$issue_pending_posts = get_posts( $args );

// loop through and set each post_status to publish
foreach( $issue_pending_posts as $pending_post ) {

$pending_post->post_status = 'publish';
wp_update_post( $pending_post );

}
add_action( 'publish_post' , 'mag_check_for_new_issue_on_publish' );
}
}
}

// register the action
add_action( 'publish_post' , 'mag_check_for_new_issue_on_publish' );