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[2011-01-28 18:15 UTC] lolbummer at gmail dot com
Description:
------------
I created an array of strings that would be typecast to integers, and cast them using a foreach loop, passing each element by reference. After dumping the resulting array, it gave (somewhat) expected results, though after dumping each element individually, it gave an unexpected result on the last element.
This happened with PHP 5.3.5 on Mac OS X Snow Leopard, but did not happen on a Debian system with PHP 5.2.6.
Test script:
---------------
<?php
$array = array('1', '2', '5324', '435', '51');
foreach($array as &$element){
$element = (int)$element;
}
var_dump($array);
foreach($array as $key => $element){
var_dump($key);
var_dump($element);
echo "\n";
}
?>
Expected result:
----------------
array(6) {
[0]=>
int(1)
[1]=>
int(2)
[2]=>
int(3)
[3]=>
int(5324)
[4]=>
int(435)
[5]=>
int(51)
}
int(0)
int(1)
int(1)
int(2)
int(2)
int(3)
int(3)
int(5324)
int(4)
int(435)
int(5)
int(51)
Actual result:
--------------
array(6) {
[0]=>
int(1)
[1]=>
int(2)
[2]=>
int(3)
[3]=>
int(5324)
[4]=>
int(435)
[5]=>
&int(51)
}
int(0)
int(1)
int(1)
int(2)
int(2)
int(3)
int(3)
int(5324)
int(4)
int(435)
int(5)
int(435)
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Last updated: Fri Apr 19 14:01:30 2024 UTC |
On PHP 5.3.5 on CentOS 5.5 - same result. Proof of concept below: echo "Result\n"; $arr = array(1,2,3,4,5); foreach($arr as &$a){ $a*=2; } foreach($arr as $a){ echo $a."\n"; } echo str_repeat('-', 10)."\nExpected\n"; $arr = array(1,2,3,4,5); $arr = array_map(function($v){ return $v*2; }, $arr); foreach($arr as $a){ echo $a."\n"; }I propose simplest testcase. It is reproduced on all my computers: PHP 5.3.6 on Windows 7 PHP 5.3.5 on Windows XP PHP 5.2.6 on Linux version 2.6.18-128.1.6.el5.centos.plus <?php $a = array( 'AAA', 'BB', 'C' ); foreach( $a as & $value ) {} foreach( $a as $value ) {} print_r( $a ); ?> Expected result: Array ( [0] => AAA [1] => BB [2] => C ) Actual result: Array ( [0] => AAA [1] => BB [2] => BB )I have a much simpler reproduction script for, I think the same error. $array = array('foo', 'bar'); foreach ($array as &$foo) { } foreach ($array as $foo) { echo "$foo\n"; } Expected result: ---------------- foo bar Actual result: -------------- foo foo Note that simply making $foo a reference is not enough. It is the double foreach on the same array, with the same variable that causes the reference to be "stuck".