php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login
Bug #78356 Array returned from ArrayAccess is incorrectly unpacked as argument
Submitted: 2019-07-31 10:56 UTC Modified: 2019-08-01 08:14 UTC
From: esurov dot tsp at gmail dot com Assigned: nikic (profile)
Status: Closed Package: Scripting Engine problem
PHP Version: 7.4Git-2019-07-31 (snap) OS: Ubuntu
Private report: No CVE-ID: None
View Add Comment Developer Edit
Welcome! If you don't have a Git account, you can't do anything here.
You can add a comment by following this link or if you reported this bug, you can edit this bug over here.
(description)
Block user comment
Status: Assign to:
Package:
Bug Type:
Summary:
From: esurov dot tsp at gmail dot com
New email:
PHP Version: OS:

 

 [2019-07-31 10:56 UTC] esurov dot tsp at gmail dot com
Description:
------------
Let some object implements ArrayAccess and its offsetGet() returns an array. Then if we use the accessed result as an unpacked (with ... token) argument we're getting an error: Indirect modification of overloaded element of class@anonymous has no effect.

Test script:
---------------
$object = new class implements ArrayAccess {
    public function offsetGet($offset)
    {
        return [1, 2];
    }
    public function offsetExists($offset)
    {
        return true;
    }
    public function offsetUnset($offset) {}
    public function offsetSet($offset, $value) {}
};
$x = max(...$object[0]);

Expected result:
----------------
$x contains 2.

Actual result:
--------------
Error: Indirect modification of overloaded element of class@anonymous has no effect

Patches

Add a Patch

Pull Requests

Add a Pull Request

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2019-07-31 12:45 UTC] cmb@php.net
-Package: SPL related +Package: Scripting Engine problem
 [2019-07-31 12:45 UTC] cmb@php.net
To clarify: this is a notice by default, not an error.  Anyhow,
this behavioral change has been introduced with commit 6913ec3[1].

[1] <http://git.php.net/?p=php-src.git;a=commit;h=6913ec3282149914e999d91b056fe1cc68d15ed7>
 [2019-07-31 15:24 UTC] nikic@php.net
The issue here is basically that ...$object[0] *might* want to modify $object[0] and the aforementioned commit actually makes that work -- unfortunately it emits this bogus notice in the case where we don't actually want to do the modification.
 [2019-08-01 08:14 UTC] nikic@php.net
-Status: Open +Status: Closed -Assigned To: +Assigned To: nikic
 [2019-08-01 08:14 UTC] nikic@php.net
I don't see a good way to fix both issues at the same time, so I'm restoring previous behavior...

Reverted in https://github.com/php/php-src/commit/afd96392a344f1b2a8aac2be375293b47f633ca4 and test added in https://github.com/php/php-src/commit/bab8b3a8bef4b5fd5c3fe75ebb1c231614ef3cfa.
 
PHP Copyright © 2001-2019 The PHP Group
All rights reserved.
Last updated: Tue Dec 10 10:01:24 2019 UTC