Edit report at https://bugs.php.net/bug.php?id=63865&edit=1
ID: 63865
Comment by: corbin dot h dot 10 at gmail dot com
Reported by: petermiller1986 at gmail dot com
Summary: php unset local reference affecting global scope
Status: Closed
Type: Bug
Package: *General Issues
Operating System: ubuntu 10.04
PHP Version: 5.3.20
Assigned To: krakjoe
Block user comment: N
Private report: N
New Comment:
@krakjoe
The problem is that a function where something is passed by value should never
permute the value passed.
You would never expect $x = ...; function f($var) { ... } f($x); to change $x.
That is unintuitive behavior.
A better illustration of it may be as follows:
<?php
function weird($arr)
{
$arr['foo'] = 'baz';
}
$a = array('foo' => 'bar', 'moo' => 'cow');
//This will leave foo as bar, as is expected
weird($a);
print_r($a);
$ref = &$a['foo'];
//Now it will change foo to baz
//This seems like very unexpected behavior?
weird($a);
print_r($a);
Previous Comments:
------------------------------------------------------------------------
[2012-12-30 15:33:57] [email protected]
You set the data in the global scope with the return of the function.
Your unset function does not receive the array by reference.
See the code below, commenting out the reference makes no difference.
<?php
function should_not_alter($in)
{
$in_ref = &$in['level1']; //try commenting out this line to see the output
change
should_only_unset_locally($in);
return $in;
}
function should_only_unset_locally(&$in)
{
unset($in['level1']['level2_0']);
}
$data[0] = array(
'level1' => array(
'level2_0' => 'first value',
'level2_1' => 'second value'
)
);
$data[1]=should_not_alter($data[0]);
print_r($data);
?>
------------------------------------------------------------------------
[2012-12-28 04:53:56] petermiller1986 at gmail dot com
Description:
------------
i have come across some very strange php behaviour. an unset which should occur
within local scope is affecting the scope of the caller function. if you run
the test script you will see that the value 'first value' has been unset from
the $data array in the global scope. however if you comment out the $in_ref =&
$in['level1']; line then the result changes (and it shouldn't i think).
is this intended behaviour of php or a bug?
Test script:
---------------
<?php
function should_not_alter($in)
{
$in_ref =& $in['level1']; //try commenting out this line to see the output
change
should_only_unset_locally($in);
return $in;
}
function should_only_unset_locally($in)
{
unset($in['level1']['level2_0']);
}
$data = array('level1' => array('level2_0' => 'first value', 'level2_1' =>
'second value'));
$data = should_not_alter($data);
print_r($data);
?>
Expected result:
----------------
Array
(
[level1] => Array
(
[level2_0] => first value
[level2_1] => second value
)
)
Actual result:
--------------
Array
(
[level1] => Array
(
[level2_1] => second value
)
)
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=63865&edit=1
