Assign second role to user

Question

I am trying to grammatically assign second 'seller' to user when the Woocommerce transaction is completed. I know that:

wp_update_user( array( 'ID' => $user_id, 'role' => 'seller' ) );

will change the role but how about adding the new one to existing serialized array. What I need in wp_capabilities is a:2:{s:7:"partner";b:1;s:6:"seller";b:1;}

Thank you!

Answer 1

If you first fetch a WP_User object with get_userdata(), you should then be able to add your additional role with the add_role() method, like so:

$user = get_userdata($user_id);
$user->add_role('partner');