How to fix pass by reference in php after upgrading to 5.6.x
I recently updated fom php 5.2 to 5.6 and there is some other code that I have not been able to fix yet:
//Finds users with the same ip- or email-address
function find_related_users($user_id) {
global $pdo;
//print_R($pdo);
//Let SQL do the magic!
$sth = $pdo->prepare('CALL find_related_users(?)');
$sth->execute(array($user_id));
//print_R($sth);
//Contains references to all users by id, to check if a user has already been processed
$users_by_id = array();
//Contains arrays of references to users by depth
$users_by_depth = array();
while ($row = $sth->fetchObject()) {
//Create array for current depth, if not present
if (!isset($users_by_depth[$row->depth]))
$users_by_depth[$row->depth] = array();
//If the user is new
if (!isset($users_by_id[$row->id])) {
//Create user array
$user = array(
'id' => $row->id,
'name' => $row->name,
'email' => $row->email,
'depth' => $row->depth,
'adverts' => array()
);
//Add all users to depth array
@array_push($users_by_depth[$row->depth], &$user);
//Add references to all users to id array (necessary to check if the id has already been processed)
$users_by_id[$row->id] = &$user;
}
//If user already exists
else
$user = &$users_by_id[$row->id];
//Add advert to user
if ($row->advert_id != null)
array_push($user['adverts'], array(
'id' => $row->advert_id,
'title' => $row->advert_title,
'msgs' => $row->msgs,
'url' => $row->url
));
#print_r($user);
//Unset $user variable !!!
//If this is missing, all references in the array point to the same user
unset($user);
}
//Return users, grouped by depth
return $users_by_depth;
}
If I just remove the ampersand in front of the dollar sign, the function stops working as intended. From other questions on stackoverflow I found that this is a call by reference and will slow down for newer php versions. However, I have not been able to find a solution.
Thanks for your help in updating this code for php 5.6.x
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Your code probably never worked as you thought it was the way you suppress errors in your call array_push()
. Note that only the first parameter array_push()
is passed by reference, the rest of the values are always passed by value.
You must remove the error suppressor @
(never use it in your own code), in which case you can also do:
$users_by_depth[$row->depth][] = &$user;
^^ add an element just like `array_push`
Now your new value in yours $users_by_depth
will contain a reference to the variable $user
.
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