Edit report at http://bugs.php.net/bug.php?id=54408&edit=1
ID: 54408
Comment by: blacknot at gmail dot com
Reported by: hitchiker at mail dot ru
Summary: Unexpected behaviour when using by-reference
iteration
Status: Bogus
Type: Bug
Package: Arrays related
Operating System: Win 7 x64, 2.6.18
PHP Version: 5.3.6
Block user comment: N
Private report: N
New Comment:
I was expecting this example;-) And I understand your point of view. But
I think that this is so because that is the realization, not because it
is better and many people faced with this and do not expect such
behavior. Thank you very much for your answers and good luck with php.
PS: Sorry for my bad english ;-)
Previous Comments:
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[2011-04-26 18:40:08] ras...@php.net
I don't understand why you don't expect references to be copied.
So, if you had code like this:
<?php
$a = 1;
$b = 2;
$c = 3;
$arr = array(&$a, $b, &$c);
$arr2 = $arr;
var_dump($arr2);
You are expecting the $a and $c references to get dropped
in $arr2?
They are not dropped. It is a by-value copy, and the by-value
copy of a reference remains a reference.
------------------------------------------------------------------------
[2011-04-26 17:12:37] blacknot at gmail dot com
In this scope is true. Variable $v must be reference, but we copy array
($tags2 = $tags;) and the last element is still reference. It is
unexpected!
------------------------------------------------------------------------
[2011-04-26 16:35:55] ras...@php.net
It is completely consistent though. You are moving that reference along
in the foreach loop. It would be inconsistent if we magically unset it.
It's not that different from something like:
for($i=0; $i<=10; $i++) echo $a[$i];
You don't really think about it, but after this loop $i is going to be
11. What you are suggesting is that either $i shouldn't be set anymore,
or that it somehow shouldn't be set to 11. It is more obvious in this
case, so perhaps it isn't unexpected for you, but it really is the same
thing.
------------------------------------------------------------------------
[2011-04-26 12:39:19] blacknot at gmail dot com
thanks Johannes, after articles I read interesting hack about unsetting
referense value: "Standard practise after any loop iteration when using
references should be an unset()"
But it is hack and unexpected behaviour
------------------------------------------------------------------------
[2011-04-26 12:24:28] johan...@php.net
I once tried to come up with some text and pictures explaining this:
http://schlueters.de/blog/archives/141-References-and-foreach.html
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