From: tomas_matousek at hotmail dot com
Operating system: WinXP
PHP version: 5.0.0RC3
PHP Bug Type: Scripting Engine problem
Bug description: Invalid array internal pointer behavior in foreach statement
Description:
------------
Array's internal pointer (which one can manipulate by next, prev, current,
etc. functions) has invalid bahavior in foreach statement. Moreover, there
is a contradictional description of this behavior in the manual.
from manual:
"Note:
Also note that foreach operates on a copy of the specified array and not
the array itself. Therefore, the ARRAY POINTER IS NOT MODIFIED as with the
each() construct, and changes to the array element returned are not
reflected in the original array. However, the INTERNAL POINTER OF THE
ORIGINAL ARRAY IS ADVANCED with the processing of the array. Assuming the
foreach loop runs to completion, the array's internal pointer will be at
the end of the array.
"
It is not clear whether or not the internal pointer of the original array
is advanced during enumeration.
I made some tests and it seems to me that foreach statement mishandles
array's internal pointer (see "reproducable code").
I would prefer if the original array's pointer was not influenced by
foreach statement because one can do changes in the array during
enumeration (which is legal since it is assumed that foreach operates on a
copy) and IMHO any changes to the pointer in original array would
necessarily lead to strange behavior.
Reproduce code:
---------------
echo "-- a --\n";
$a = array(0,1,2);
var_dump(current($a));
foreach ($a as $value)
{
/* do not touch $a */
}
var_dump(current($a));
$b = array(0,1,2);
echo "-- b --\n";
var_dump(current($b));
foreach ($b as $value)
{
var_dump(current($b));
}
var_dump(current($b));
Expected result:
----------------
either the following (pointer is advanced):
-- a --
int(0)
bool(false)
-- b --
int(0)
int(0)
int(1)
int(2)
int(false)
or the following (pointer is not avanced):
-- a --
int(0)
int(0)
-- b --
int(0)
int(0)
int(0)
int(0)
int(0)
Actual result:
--------------
-- a --
int(0)
bool(false)
-- b --
int(0)
int(0)
int(0)
int(0)
int(0)
--
Edit bug report at http://bugs.php.net/?id=28939&edit=1
--
Try a CVS snapshot (php4): http://bugs.php.net/fix.php?id=28939&r=trysnapshot4
Try a CVS snapshot (php5): http://bugs.php.net/fix.php?id=28939&r=trysnapshot5
Fixed in CVS: http://bugs.php.net/fix.php?id=28939&r=fixedcvs
Fixed in release: http://bugs.php.net/fix.php?id=28939&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=28939&r=needtrace
Need Reproduce Script: http://bugs.php.net/fix.php?id=28939&r=needscript
Try newer version: http://bugs.php.net/fix.php?id=28939&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=28939&r=support
Expected behavior: http://bugs.php.net/fix.php?id=28939&r=notwrong
Not enough info: http://bugs.php.net/fix.php?id=28939&r=notenoughinfo
Submitted twice: http://bugs.php.net/fix.php?id=28939&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=28939&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=28939&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=28939&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=28939&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=28939&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=28939&r=float
