when using add_user_to_blog getting error "Call to undefined function get_userdata"

Question

I am working on WordPress MU and trying to build one plugin to add user to multiple sites. so far did everything to loop through sites. But while assigning user to site as below using add_user_to_blog am getting error see below.

add_user_to_blog( $blogid, $amsuserid, $urole );

Getting the following error:

Fatal error: Call to undefined function get_userdata() in wp-includes\ms-functions.php on line 181

if I disable the line "add_user_to_blog" no errors.

full function here:

function amsAddUsertoSites()
{

    $siteslist=$_POST['updatesites'];
    $urole=$_POST['setrole'];
    $addtoallblogs=$_POST['allsites'];
    $amsuserid=$_POST['userid'];


      if($addtoallblogs) {
      //add_user_to_blog( $blogid, $user_id, "administrator" );
            $blogs = get_blogs();
            foreach($blogs as $blog=>$blogid)   
            {
                    add_user_to_blog( $blogid, $amsuserid,$urole );
            }

       }
       else {

       foreach($siteslist as $blog=>$blogid)   
            {
                    add_user_to_blog( $blogid, $amsuserid,$urole );
            }


       }

}

Answer 1

get_userdata() is a pluggable function, you can find its declaration in wp-includes/pluggable.php. That means, plugins can declare it earlier, and it is not declared, when a plugin is loaded.

When you look at wp-settings.php, you can see the load order:

// Load active plugins.
foreach ( wp_get_active_and_valid_plugins() as $plugin )
    include_once( $plugin );
unset( $plugin );

// Load pluggable functions.
require( ABSPATH . WPINC . '/pluggable.php' );
require( ABSPATH . WPINC . '/pluggable-deprecated.php' );

// Set internal encoding.
wp_set_internal_encoding();

// Run wp_cache_postload() if object cache is enabled and the function exists.
if ( WP_CACHE && function_exists( 'wp_cache_postload' ) )
    wp_cache_postload();

/**
 * Fires once activated plugins have loaded.
 *
 * Pluggable functions are also available at this point in the loading order.
 *
 * @since 1.5.0
 */
do_action( 'plugins_loaded' );

Wait at least for plugins_loaded, before you do more than calling add_action() or add_filter().