get_user does not returns specific roles

[dejudicibus]

If I use get_users to return only the 'authors' by using the following code:

$user_options = array(
  'orderby' => 'display_name',
  'order'   => 'ASC',
  'role'    => 'author',
  'who'     => 'authors'
); 
$all_authors = get_users($users_options); 
foreach ($all_authors as $author) {
 if ($author->ID > 1) {
   /* do something */
 }
}

I get back all users but admin, that is, also subscribers.

If you only want users with the 'author' role, remove the 'who' parameter. If you want all users who can create posts, remove the 'role' parameter. Using both doesn't make sense.

To further explain what is going on, 'who' => 'authors' selects all users of the blog who are not subscribers (using user_level != 0).

role=author is more restrictive. However, when who=authors is specified, $blog_id gets set to 0, which prevents role=author from being processed. The processing is a bit wonky, but this is proper behavior. Choose one or the other — who=authors is simply a shortcut that returns a superset of role=author.

You shouldn't be receiving subscribers back. who=authors should prevent that. Your subscribers likely have a wp_user_level of > 0, which is incorrect for subscribers.