Description:
------------
$report['errors']['linkedin'][] = CLinkedinApiHelper::api()->postToGroup('',$article['title'], $description, $content);

array_filter($report['errors']['linkedin']);

when function return's nothing, array creating new item $report['errors']['linkedin'][0] => null, but array_filter do not react on it, it is only react when function return null directly.

Test script:
---------------
$report['errors']['linkedin'][] = CLinkedinApiHelper::api()->postToGroup('',$article['title'], $description, $content);
//part of helper function:

if ($data['linkedin']) {
 $xml = simplexml_load_string($data['linkedin']);

 if (isset($xml->{'error-code'})) {
 $message = sprintf($xml->message);
 return $message;
 }
}

return null; //if remove this, array_filter do not see new "NULL" array item

array_filter($report['errors']['linkedin']);

Expected result:
----------------
array(0) {}

Actual result:
--------------
array(1) {
  [0]=>
  NULL
}