#39276 [Opn->Bgs]: Unpredictable behaviour of references
| From: | tony2001@php.net | Date: | Fri, 27 Oct 2006 10:13:12 +0000 |
| Subject: | #39276 [Opn->Bgs]: Unpredictable behaviour of references | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-104065@lists.php.net to get a copy of this message | ||
ID: 39276
Updated by: tony2001@php.net
Reported By: plyrvt at mail dot ru
-Status: Open
+Status: Bogus
Bug Type: Variables related
Operating System: any
PHP Version: 5.1.6
New Comment:
This is expected and predictable.
When an array contains references, they still remain references, even
if the array is copied.
Previous Comments:
------------------------------------------------------------------------
[2006-10-27 10:06:54] plyrvt at mail dot ru
Sorry, 1a & 1b were messed up. Correct is:
1a. Element of an array is passed 'by value' and can be modified
independently
1b. Whole array can not be passed 'by value'. It is forced to be passed
by reference.
------------------------------------------------------------------------
[2006-10-27 09:56:57] plyrvt at mail dot ru
Description:
------------
Depending on context, references can have 3 different behaviours:
1. Reference to element of an array. Element becomes reference
automatically until that reference exist.
1a. Whole array is passed 'by value' and keys of array copy can be
modified independently
1b. Element of an array can not be passed 'by value'. It is forced to
be passed by reference.
2. Reference to regular variable. Variable does not become reference
and can be passed 'by value'
Reproduce code:
---------------
<?php
function bla1($param){ $param['k1']="new!"; }
function bla2($param){ $param="new!";}
$a['k1']='foo';;
echo var_dump($a);
echo "<hr>";
$v=&$a['k1'];
echo var_dump($a);
echo "<hr>";
bla2($a['k1']);
echo var_dump($a);
echo "<hr>";
bla1($a);
echo var_dump($a);
echo "<hr>";
unset($v);
echo var_dump($a);
echo "<hr>";
$k1='foo';
echo var_dump($k1);
echo "<hr>";
$v=&$k1;
echo var_dump($k1);
echo "<hr>";
bla2($k1);
echo var_dump($k1);
echo "<hr>";
unset($v);
echo var_dump($k1);
?>
Expected result:
----------------
any predictable output
Actual result:
--------------
array(1) { ["k1"]=> string(3) "foo" }
array(1) { ["k1"]=> &string(3) "foo" }
array(1) { ["k1"]=> &string(3) "foo" }
array(1) { ["k1"]=> &string(4) "new!" }
array(1) { ["k1"]=> string(4) "new!" }
--------------
string(3) "foo"
string(3) "foo"
string(3) "foo"
string(3) "foo"
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=39276&edit=1