php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login

go to bug id or search bugs for

Bug #71240 array_filter byref value in callable no longer working
Submitted: 2015-12-29 20:05 UTC Modified: 2015-12-30 03:57 UTC
Votes:1
Avg. Score:5.0 ± 0.0
Reproduced:1 of 1 (100.0%)
Same Version:1 (100.0%)
Same OS:0 (0.0%)
From: donatj at gmail dot com Assigned:
Status: Not a bug Package: *General Issues
PHP Version: 7.0.1 OS:
Private report: No CVE-ID: None
View Developer Edit
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: donatj at gmail dot com
New email:
PHP Version: OS:

 

 [2015-12-29 20:05 UTC] donatj at gmail dot com 
Description:
------------
It would appear that passing by reference in the callable of array_filter no longer functions as expected.  I can find no documentation of this change on the array_filter page.

The expected result is seen in 5.3 -> 5.6

Test script:
---------------
<?php

$files = array('AAA', 'BBB', 'CcC');

$files = array_filter($files, function ( &$path ) {
	$path = strtolower($path);
	return true;
});

print_r($files);

Expected result:
----------------
Array
(
    [0] => aaa
    [1] => bbb
    [2] => ccc
)

Actual result:
--------------
Array
(
    [0] => AAA
    [1] => BBB
    [2] => CcC
)

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2015-12-29 20:57 UTC] requinix@php.net
-Status: Open +Status: Not a bug
 [2015-12-29 20:57 UTC] requinix@php.net 
I don't see anything to suggest that was supported in the first place. There aren't even user comments doing that.

Besides, if you want to alter the array values then array_map() is more appropriate.
 [2015-12-29 20:58 UTC] nikic@php.net
-Status: Not a bug +Status: Verified
 [2015-12-29 20:58 UTC] nikic@php.net 
@requinix: The issue here is that is does the by-reference modification, while it should not. A similar, but slightly different, bug exists in HHVM as well: https://3v4l.org/dp6Lt
 [2015-12-29 21:03 UTC] requinix@php.net 
Fair enough. It just looked like one more of the various inconsistencies with references that was fixed with 7.
 [2015-12-29 22:22 UTC] nikic@php.net
-Status: Verified +Status: Not a bug
 [2015-12-29 22:22 UTC] nikic@php.net 
@requinix: Actually I'm just stupid, you are totally right. I got confused with which output is which.
 [2015-12-29 22:39 UTC] donatj at gmail dot com 
I still argue it's a bug. It's a behaviour that goes way back to at least 4.3.0 https://3v4l.org/iTqYI 

If nothing else, the change should be noted in the array_filter documentation, but I'd still argue it should be fixed.
 [2015-12-29 22:46 UTC] donatj at gmail dot com 
Also the use case for this - I'm array_filter-ing already, not with a hardcoded true but actual logic, and as the code is already looping over items having a second loop through my array with array_map is silly.
 [2015-12-29 23:11 UTC] nikic@php.net 
array_filter() is documented as taking the $array by value. It's not *allowed* to modify the original array in any way. Modifying the array violates basic semantics of by-value argument passing.
 [2015-12-30 03:57 UTC] yohgaki@php.net 
Just an additional comment on this.
array_filter() is function filters array elements. To modify passed array itself, one should use array_walk()/array_walk_recursive()

http://php.net/manual/en/function.array-walk.php

I've seen this misuse on occasion. Nice to see this bug is fixed in PHP 7.
 
PHP Copyright © 2001-2025 The PHP Group
All rights reserved. 		Last updated: Sat May 10 04:01:29 2025 UTC