PHP Gotchas

phpgotchas.md

SplPriorityQueue Does Not Behave Like a Queue

SplPriorityQueue is advertised as a prioritized queue. Ideally, as a queue, when adding items of the same priority, the items should retain the same order as how they were registered (FIFO). In PHP the order is unexpected:

<?php
$queue = new SplPriorityQueue();
$queue->insert('1',0);
$queue->insert('2',0);
$queue->insert('3',0);
$queue->insert('4',0);
$queue->insert('5',0);

while($queue->valid()){
    var_dump( $queue->current() );
    $queue->next();
}

Output:

string(1) "1"
string(1) "5"
string(1) "4"
string(1) "3"
string(1) "2"

• Demo: https://3v4l.org/eNXSo
• Bug Wont Fix: https://bugs.php.net/bug.php?id=53710