Iterating within function moves original array pointer

Bug #40705

Submitted:

2007-03-03 12:31 UTC

Modified:

2007-07-24 19:26 UTC

Votes:	16
Avg. Score:	5.0 ± 0.0
Reproduced:	16 of 16 (100.0%)
Same Version:	16 (100.0%)
Same OS:	4 (25.0%)

From:

avb@php.net

Assigned:

dmitry (profile)

Status:

Closed

Package:

Arrays related

PHP Version:

5.2.1

OS:

Irrelevant

Private report:

CVE-ID:

None

[2007-03-03 12:31 UTC] avb@php.net

Description:
------------
If an array is passed by value to the function and is iterated over within said function, the "internal pointer" of the original array is moved.


Reproduce code:
---------------
function doForeach($array)
{
    foreach ($array as $k => $v) {
        // do stuff
    }
}

$foo = array('foo', 'bar', 'baz');

doForeach($foo);

var_dump(key($foo));


Expected result:
----------------
int(0) (returned by versions prior to 5.2.1)

Actual result:
--------------
NULL (returned by version 5.2.1 and current 5.2 snapshot)

Patches

Pull Requests

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[2007-03-19 19:59 UTC] ashnazg@php.net

Tested this example against the 5.2.1 zipfile from php.net on WinXP and the problem does occur.

Also tested it against the 5.2 snapshot (php5.2-win32-200703191630.zip) from php.net, on WinXP, and the problem seems to still exist.

[2007-05-03 10:24 UTC] jamesgauth at gmail dot com

This problem occurs in copies of an object's properties too. The array pointer is advanced by foreach in both the original and the copied variable.

<?php

class foo {

	var $arr = array(1, 2, 3);
	
	function test() {
	
		var_dump(key($this->arr));
		
		$array_copy = $this->arr;
		foreach ($array_copy as $val) {}
		
	}
	
}

$a = new foo();
$a->test();
$a->test();

?>

[2007-07-24 19:26 UTC] dmitry@php.net

This bug has been fixed in CVS.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
 
Thank you for the report, and for helping us make PHP better.