Bug #64693 [Opn->Nab]: Third argument ($initial) passed to array_reduce should be immutable.
Edit report at https://bugs.php.net/bug.php?id=64693&edit=1
ID: 64693
Updated by: nikic@php.net
Reported by: jdoane at vlacs dot org
Summary: Third argument ($initial) passed to array_reduce
should be immutable.
-Status: Open
+Status: Not a bug
Type: Bug
Package: Arrays related
Operating System: Ubuntu 12.04.02 LTS
PHP Version: 5.3.24
Block user comment: N
Private report: N
New Comment:
array_reduce uses the normal passing semantics. We do not document for every function that it uses
the normal passing semantics, because, well, they are the same everywhere.
PHP never clones your objects unless you tell it to.
Previous Comments:
------------------------------------------------------------------------
[2013-04-23 13:04:13] jdoane at vlacs dot org
The order of the expected output is backwards, I apologize.
It should be:
~$ php test.php
stdClass Object
(
[count] => 2
[maxlen] => 5
)
stdClass Object
(
[count] => 0
[maxlen] => 0
)
------------------------------------------------------------------------
[2013-04-22 19:41:14] jdoane at vlacs dot org
Description:
------------
When array_reduce is called with an object as the third argument, the variable
passed to said third argument will turn into the result of the array_reduce()
call. It feels like the object getting passed into array_reduce is not being
cloned and is being modified in place. Since all objects are passed as a reference
it changes the "$initial" variable in the scope where array_reduce was called.
So either documentation needs to be updated that says that $initial gets set to
the return value when it is an object or this shouldn't happen to begin with as it
appears that $initial should remain immutable for the duration of the
array_reduce() call.
Test script:
---------------
$array = (object)Array('foo', 'baraz');
$initial = (object)Array('count' => 0, 'maxlen' => 0);
$output = array_reduce($array, function(&$d, $item) {
if($d->maxlen < strlen($d)) { $d->maxlen = strlen($d); }
$d->count++;
return $d;
}
print_r($output);
print_r($initial);
Expected result:
----------------
~$ php test.php
stdClass Object
(
[count] => 0
[maxlen] => 0
)
stdClass Object
(
[count] => 2
[maxlen] => 5
)
Actual result:
--------------
~$ php test.php
stdClass Object
(
[count] => 2
[maxlen] => 5
)
stdClass Object
(
[count] => 2
[maxlen] => 5
)
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=64693&edit=1
Thread (5 messages)