php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login
Bug #79715 After the array element reference changes, use array_merge function produc
Submitted: 2020-06-19 07:52 UTC Modified: 2020-06-19 08:08 UTC
From: xyzzxf_2013 at 163 dot com Assigned:
Status: Not a bug Package: Unknown/Other Function
PHP Version: 7.3.4nts OS: centos 7/window 10
Private report: No CVE-ID: None
Welcome back! If you're the original bug submitter, here's where you can edit the bug or add additional notes.
If you forgot your password, you can retrieve your password here.
Password:
Status:
Package:
Bug Type:
Summary:
From: xyzzxf_2013 at 163 dot com
New email:
PHP Version: OS:

 

 [2020-06-19 07:52 UTC] xyzzxf_2013 at 163 dot com
Description:
------------
Reference value modification of element of array

Test script:
---------------
$a = ['23','25','26'];
foreach ($a as &$v) {
    $v = $v+1;
}
function get_check_code($data)
{
    foreach ($data as &$a) {
        $a = hexdec($a);
    }
    $sum = dechex(array_sum($data));
    return substr($sum, -2);
}
var_dump($a);
$b = get_check_code($a);
$c = array_merge($a,[$b]);
print_r($c);

Expected result:
----------------
var_dump($a) output array(3) { [0] => int(24) [1] => int(26) [2] => int(27) }

print_r($c) output Array ( [0] => 24 [1] => 26 [2] => 39 [3] => 71 )

Actual result:
--------------
The expected result of print_r($c) is Array ( [0] => 24 [1] => 26 [2] => 27 [3] => 71 )  or  Array ( [0] => 36 [1] => 38 [2] => 39 [3] => 71 )

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2020-06-19 07:57 UTC] xyzzxf_2013 at 163 dot com
-PHP Version: 7.2.31 +PHP Version: 7.3.4nts
 [2020-06-19 07:57 UTC] xyzzxf_2013 at 163 dot com
php version
 [2020-06-19 08:02 UTC] stas@php.net
-Type: Security +Type: Bug
 [2020-06-19 08:08 UTC] nikic@php.net
-Status: Open +Status: Not a bug
 [2020-06-19 08:08 UTC] nikic@php.net
See https://www.php.net/manual/en/language.references.whatdo.php for how arrays and references interact. In particular, even if you pass an array by-value, it still retains any internal references. If your case, there is an active reference to the last array element. You can drop it by calling unset($v) after the foreach loop.

tl;dr Don't use references, just don't.
 
PHP Copyright © 2001-2024 The PHP Group
All rights reserved.
Last updated: Mon Dec 02 21:01:30 2024 UTC