#39011 [Opn]: foreach($_GET as $key = $value) causes later bugs passing $_GET as a paramete
ID: 39011
User updated by: php_bug dot email at email dot digiways dot com
Reported By: php_bug dot email at email dot digiways dot com
Status: Open
Bug Type: Arrays related
Operating System: Windows XP
PHP Version: 5.1.6
New Comment:
This problem affects all the arrays and not just the $_GET one. Please
note that $value is not reused outside of the foreach loop. Effectively
this renders foreach by reference useless.
Another very simple script which reproduces the problem:
$myarray = array( 'mykey' = 'foo' );
function doit($tmp) { $tmp['mykey'] = 'bar'; }
foreach($myarray as $key = $value) {}
echo $myarray['mykey'].\n;
doit($myarray);
echo $myarray['mykey'].\n;
and outputs
foo
bar
instead of
foo
foo
Previous Comments:
[2006-10-01 21:00:11] php_bug dot email at email dot digiways dot com
Where exactly is this behaviour documented? Can you point to the
documentation page as I failed to find this.
Also, another defect http://bugs.php.net/bug.php?id=29992 which was
referenced here is a different problem. In my case I do not reuse the
reference variable $value .
[2006-10-01 20:39:17] [EMAIL PROTECTED]
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php
bogus
[2006-10-01 20:24:34] judas dot iscariote at gmail dot com
this is the expected behaviuor, and not a bug. :P
the reasons are clearly explained by gardan at gmx dot de on this
report, please do a search before reporting
http://bugs.php.net/bug.php?id=29992
[2006-10-01 20:13:53] sitnikov at infonet dot ee
confirmed with PHP Version 5.2.0RC5-dev
[2006-10-01 19:25:34] php_bug dot email at email dot digiways dot com
Description:
if we iterate over $_GET using references (see the example) and pass
$_GET to a function, function modifies $_GET and not the local copy.
For example, save the example code in test.php and open
test.php?mykey=foo
.
Reproduce code:
---
?php
function doit($http_get_params)
{
$http_get_params['mykey'] = 'bar';
echo 'br/'.$_GET['mykey'];
}
foreach($_GET as $key = $value) {}
echo 'br/'.$_GET['mykey'];
doit($_GET);
echo 'br/'.$_GET['mykey'];
?
Expected result:
When we open test.php?mykey=foo I expect to see
foo
foo
foo
Actual result:
--
When we open test.php?mykey=foo we actually see
foo
bar
bar
--
Edit this bug report at http://bugs.php.net/?id=39011edit=1
#39011 [Opn]: foreach($_GET as $key = $value) causes later bugs passing $_GET as a paramete
ID: 39011
User updated by: php_bug dot email at email dot digiways dot com
Reported By: php_bug dot email at email dot digiways dot com
Status: Open
Bug Type: Arrays related
Operating System: Windows XP
PHP Version: 5.1.6
New Comment:
Documentation describes that parameters are passed to functions by
value by default. And since the behaviour you are talking about is not
documented anywhere, it is definitely a bug.
So, I suggest you read PHP documentation starting with
http://www.php.net/manual/en/functions.arguments.php
which clearly states:
===
By default, function arguments are passed by value (so that if you
change the value of the argument within the function, it does not get
changed outside of the function). If you wish to allow a function to
modify its arguments, you must pass them by reference.
===
and then explain it again why the problem described above is not a bug
although it does not do what PHP documentation states it does.
Previous Comments:
[2006-10-01 22:34:35] judas dot iscariote at gmail dot com
again, THIS IS NOT A BUG ยก!
but yes,this behaviuor should be described in the documentation I
think.
I still think this kind of code should raise an E_WARNING or something
( the idea was proposed a while ago, but refused)
[2006-10-01 22:12:20] plyrvt at mail dot ru
This bug can be described shortly:
Existance of a reference to the element of an array prevents this
element to be passed by value as long as any reference point to it
[2006-10-01 22:02:06] php_bug dot email at email dot digiways dot com
Actually this is not just about foreach, this is the generic problem
with references.
Apparently if you have a reference to an array element, then when you
pass that array to a function and modify that element in the function,
then the external array is modified as well, and not just the copy
passed to the function.
A small example which shows the problem:
$myarray = array( 'mykey' = 'foo' );
function doit($tmp) { $tmp['mykey'] = 'bar'; }
$value = $myarray['mykey'];
echo $myarray['mykey'].\n;
doit($myarray);
echo $myarray['mykey'].\n;
Once again - can anyone point to the documentation page which explains
this behaviour ?
[2006-10-01 21:55:23] plyrvt at mail dot ru
If you add unset($val) after foreach, original array starts back to
work as expected:
?php
$a['b']='foo';
function boo($_params){
$_params['b'] = 'bar';
echo $_params['b'];
}
foreach($a as $key = $val) {}
unset($val);
echo $a['b'];
boo($a);
echo $a['b'];
/*
foo
bar
foo
*/
?
[2006-10-01 21:39:58] plyrvt at mail dot ru
Confirm with 5.1.6:
?php
$a['b']='foo';
function boo($_params){
$_params['b'] = 'bar';
echo $a['b'];
}
foreach($a as $key = $val) {} // ?!
echo $a['b'];
boo($a);
echo $a['b'];
?
If you comment out `foreach` loop or remove near `$val`, code works
OK. Loop does nothing and $val is *never* mentioned in code elsewhere.
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
http://bugs.php.net/39011
--
Edit this bug report at http://bugs.php.net/?id=39011edit=1
#39011 [Opn]: foreach($_GET as $key = $value) causes later bugs passing $_GET as a paramete
ID: 39011
User updated by: php_bug dot email at email dot digiways dot com
Reported By: php_bug dot email at email dot digiways dot com
Status: Open
Bug Type: Arrays related
Operating System: Windows XP
PHP Version: 5.1.6
New Comment:
Actually this is not just about foreach, this is the generic problem
with references.
Apparently if you have a reference to an array element, then when you
pass that array to a function and modify that element in the function,
then the external array is modified as well, and not just the copy
passed to the function.
A small example which shows the problem:
$myarray = array( 'mykey' = 'foo' );
function doit($tmp) { $tmp['mykey'] = 'bar'; }
$value = $myarray['mykey'];
echo $myarray['mykey'].\n;
doit($myarray);
echo $myarray['mykey'].\n;
Once again - can anyone point to the documentation page which explains
this behaviour ?
Previous Comments:
[2006-10-01 21:55:23] plyrvt at mail dot ru
If you add unset($val) after foreach, original array starts back to
work as expected:
?php
$a['b']='foo';
function boo($_params){
$_params['b'] = 'bar';
echo $_params['b'];
}
foreach($a as $key = $val) {}
unset($val);
echo $a['b'];
boo($a);
echo $a['b'];
/*
foo
bar
foo
*/
?
[2006-10-01 21:39:58] plyrvt at mail dot ru
Confirm with 5.1.6:
?php
$a['b']='foo';
function boo($_params){
$_params['b'] = 'bar';
echo $a['b'];
}
foreach($a as $key = $val) {} // ?!
echo $a['b'];
boo($a);
echo $a['b'];
?
If you comment out `foreach` loop or remove near `$val`, code works
OK. Loop does nothing and $val is *never* mentioned in code elsewhere.
[2006-10-01 21:37:06] php_bug dot email at email dot digiways dot com
This problem affects all the arrays and not just the $_GET one. Please
note that $value is not reused outside of the foreach loop. Effectively
this renders foreach by reference useless.
Another very simple script which reproduces the problem:
$myarray = array( 'mykey' = 'foo' );
function doit($tmp) { $tmp['mykey'] = 'bar'; }
foreach($myarray as $key = $value) {}
echo $myarray['mykey'].\n;
doit($myarray);
echo $myarray['mykey'].\n;
and outputs
foo
bar
instead of
foo
foo
[2006-10-01 21:00:11] php_bug dot email at email dot digiways dot com
Where exactly is this behaviour documented? Can you point to the
documentation page as I failed to find this.
Also, another defect http://bugs.php.net/bug.php?id=29992 which was
referenced here is a different problem. In my case I do not reuse the
reference variable $value .
[2006-10-01 20:39:17] [EMAIL PROTECTED]
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php
bogus
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
http://bugs.php.net/39011
--
Edit this bug report at http://bugs.php.net/?id=39011edit=1
