Elgg-Lorea-Hydra/mod/group_tools/actions/admin/fix_auto_join.php

<?php
/**
 * Make sure everyone is a member of the autojoin group
 */

// this could take a while ;)
set_time_limit(0);

$group_guid = (int) get_input("group_guid");

if (!empty($group_guid)) {
	$group = get_entity($group_guid);
	
	if (!empty($group) && ($group instanceof ElggGroup)) {
		// set counters
		$already = 0;
		$new = 0;
		$failure = 0;
		
		$options = array(
			"type" => "user",
			"relationship" => "member_of_site",
			"relationship_guid" => elgg_get_site_entity()->getGUID(),
			"inverse_relationship" => true,
			"limit" => false,
		);
		
		$users = new ElggBatch("elgg_get_entities_from_relationship", $options);
		foreach ($users as $user) {
			if (!$group->isMember($user)) {
				if ($group->join($user)) {
					$new++;
				} else {
					$failure++;
				}
			} else {
				$already++;
			}
		}
		
		system_message(elgg_echo("group_tools:action:fix_auto_join:success", array($new, $already, $failure)));
	} else {
		register_error(elgg_echo("group_tools:action:error:entity"));
	}
} else {
	register_error(elgg_echo("group_tools:action:error:input"));
}

forward(REFERER);