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

go to bug id or search bugs for

Request #76613 Argument unpacking: Add support for associative arrays
Submitted: 2018-07-12 02:09 UTC Modified: 2018-07-12 04:46 UTC
Votes:12
Avg. Score:4.0 ± 0.9
Reproduced:12 of 12 (100.0%)
Same Version:5 (41.7%)
Same OS:5 (41.7%)
From: nowm at yandex dot ru Assigned:
Status: Suspended Package: Arrays related
PHP Version: 5.6.36 OS: any
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: nowm at yandex dot ru
New email:
PHP Version: OS:

 

 [2018-07-12 02:09 UTC] nowm at yandex dot ru 
Description:
------------
This request is related to any PHP 5.6+

When you pass an associative array for argument unpacking (https://wiki.php.net/rfc/argument_unpacking), you get a fatal error, "Cannot unpack array with string keys".

As I see, there are no reasons to limit unpacking to only numeric arrays. For example, it does not use numeric keys for ordering values, so key type has no any sense:

<?php
$array = [1 => 'b', 2 => 'c', 0 => 'a'];

// Outputs "b c a", not "a b c"
// It shows that array unpacking does not rely on keys at all
var_dump(...$array);

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

$array = ['a' => 'one', 'b' => 'two', 'c' => 'three'];

var_dump(...$array);

Expected result:
----------------
string(3) "one"
string(3) "two"
string(5) "three"

Actual result:
--------------
PHP Fatal error:  Uncaught Error: Cannot unpack array with string keys in Standard input code:5

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2018-07-12 02:38 UTC] requinix@php.net
-Status: Open +Status: Suspended
 [2018-07-12 02:38 UTC] requinix@php.net 
> In order to ensure forward-compatibility with named arguments the unpacking operator does not support string keys.

That particular RFC is no longer active but the feature as a whole still has its proponents.
 [2018-07-12 03:00 UTC] nowm at yandex dot ru 
requinix, but an associative array is the ideal fit for named arguments unpacking, am I wrong?

<?php
$string = 'some string';
htmlspecialchars(...['string' => $string, 'double_encode' => false]);

Anyway, thank you for the review, even if the request was suspended.
 [2018-07-12 03:04 UTC] requinix@php.net 
> an associative array is the ideal fit for named arguments unpacking, am I wrong?
You're right, it would be good for named arguments. Which is why the current version of unpacking specifically does not allow it, so that if/when named arguments are supported, unpacking can be supported without breaking backwards compatibility.
 [2018-07-12 03:54 UTC] nowm at yandex dot ru 
> so that if/when named arguments are supported, unpacking can be supported without breaking backwards compatibility

But backward compatibility already will be broken in any case, because, for example, the "call_user_func_array" function allows associative arrays. So when (or if) named arguments are supported, a lot of code will be broken. I saw a lot of code that using associative arrays in the "call_user_func_array".

<?php
// It works!
call_user_func_array('var_dump', ['a' => 1, 'b' => 'two']);
 [2018-07-12 04:46 UTC] requinix@php.net 
Whether or not such code would be broken is a matter for the implementation of named arguments, but at a minimum has nothing to do with array unpacking.
 
PHP Copyright © 2001-2025 The PHP Group
All rights reserved. 		Last updated: Fri Mar 14 15:01:30 2025 UTC