Create dynamic group fails with SELECT DISTINCT

as an example I use this custom search module :
https://wiki.civicrm.org/confluence/display/CRMDOC/Custom+Search+Include+Exclude+Groups+and+Tags+with+and_or
only modification :
$tags =& CRM_Core_PseudoConstant::tag( );
to
$tags=0;#& CRM_Core_PseudoConstant::tag( );

no problem for searching. but when I try to save the search I get a DB error.

reading at the error; something has been inserted between the SELECT and the DISTINCT. Which is the cause of the SQL error.
I got to the file /html/wp-content/plugins/civicrm/civicrm/CRM/Contact/BAO/GroupContactCache.php(543) to see 20 lines before :

if ($sql)

{ $sql = preg_replace("/^\s*SELECT/", "SELECT $groupID as group_id, ", $sql); }

this bad regex inserting without knowledge of mysql syntax something between SELECT and DISTINCT is the root of the problem.