php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login
Bug #76800 foreach inconsistent if array modified during loop
Submitted: 2018-08-27 08:29 UTC Modified: 2018-08-27 11:39 UTC
Votes:2
Avg. Score:3.0 ± 0.0
Reproduced:1 of 2 (50.0%)
Same Version:0 (0.0%)
Same OS:0 (0.0%)
From: leonix at motd dot ru Assigned: dmitry (profile)
Status: Closed Package: Arrays related
PHP Version: 7.2.9 OS:
Private report: No CVE-ID: None
 [2018-08-27 08:29 UTC] leonix at motd dot ru
Description:
------------
Hey. I encountered a weird inconsistency in foreach() behavior over plain arrays. See the code below. In certain specific cases loop will skip second iteration with no apparent reason.

It reproduces (at least) on 7.2.7-7.2.9 on both windows and linux, but NOT on 7.1.21 or below.

Test script:
---------------
$arr = [1 => 1, 3 => 3];           // [1 => 1, 2 => 3] will print both keys
foreach($arr as $key => &$val) {   // without & will print both keys
    echo "See key {$key}\n";
    $arr[0] = 0;                   // without this line will print both keys
    unset($arr[0]);
}


Expected result:
----------------
See key 1
See key 3


Actual result:
--------------
See key 1


Patches

Add a Patch

Pull Requests

Add a Pull Request

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2018-08-27 09:16 UTC] cmb@php.net
-Status: Open +Status: Verified
 [2018-08-27 09:16 UTC] cmb@php.net
Behavior confirmed: <https://3v4l.org/8Oi0k> vs. <https://3v4l.org/MpCBe>.
 [2018-08-27 11:39 UTC] cmb@php.net
-Assigned To: +Assigned To: dmitry
 [2018-08-27 11:39 UTC] cmb@php.net
The regression seems to have been introduced with commit
31a2198[1].  Dmitry, could you please have a look?

[1] <http://git.php.net/?p=php-src.git;a=commit;h=31a2198>
 [2018-09-14 07:33 UTC] dmitry@php.net
Automatic comment on behalf of dmitry@zend.com
Revision: http://git.php.net/?p=php-src.git;a=commit;h=3bc4a63fc27768c665fcbc101db4e579c761833b
Log: Fixed bug #76800 (foreach inconsistent if array modified during loop)
 [2018-09-14 07:33 UTC] dmitry@php.net
-Status: Verified +Status: Closed
 
PHP Copyright © 2001-2018 The PHP Group
All rights reserved.
Last updated: Thu Oct 18 23:01:25 2018 UTC