From:             ian at ithomas dot name
Operating system: Gentoo
PHP version:      5.2.3
PHP Bug Type:     Math related
Bug description:  Decrementing null is null

Description:
------------
Incrementing null is 1.
Decrementing null is null!

I'm not sure which is the correct behaviour, but they should at least be
consistent.


I saw this on PHP 4.4.4 but have since duplicated it on 5.2.3. It was a
problem for me because I had a "for ($i = null; $i > 0; $i--)" which
results in an infinite loop (but would work fine if $i++ was used
instead).


Reproduce code:
---------------
<?php
echo '$i++: ';
$i = null;
var_dump($i);
$i++;
var_dump($i);

echo '<br> <br> <br> $i--: ';
$i = null;
var_dump($i);
$i--;
var_dump($i);

echo '<br> <br> <br> $i - 1: ';
$i = null;
var_dump($i);
$i = $i - 1;
var_dump($i);
?>

Expected result:
----------------
null-- should be 1, so script should output:

$i++: NULL int(1)


$i--: NULL int(-1)


$i - 1: NULL int(-1) 

Actual result:
--------------
null-- is null, script output is:


$i++: NULL int(1)


$i--: NULL NULL


$i - 1: NULL int(-1) 

-- 
Edit bug report at http://bugs.php.net/?id=41690&edit=1
-- 
Try a CVS snapshot (PHP 4.4): 
http://bugs.php.net/fix.php?id=41690&r=trysnapshot44
Try a CVS snapshot (PHP 5.2): 
http://bugs.php.net/fix.php?id=41690&r=trysnapshot52
Try a CVS snapshot (PHP 6.0): 
http://bugs.php.net/fix.php?id=41690&r=trysnapshot60
Fixed in CVS:                 http://bugs.php.net/fix.php?id=41690&r=fixedcvs
Fixed in release:             
http://bugs.php.net/fix.php?id=41690&r=alreadyfixed
Need backtrace:               http://bugs.php.net/fix.php?id=41690&r=needtrace
Need Reproduce Script:        http://bugs.php.net/fix.php?id=41690&r=needscript
Try newer version:            http://bugs.php.net/fix.php?id=41690&r=oldversion
Not developer issue:          http://bugs.php.net/fix.php?id=41690&r=support
Expected behavior:            http://bugs.php.net/fix.php?id=41690&r=notwrong
Not enough info:              
http://bugs.php.net/fix.php?id=41690&r=notenoughinfo
Submitted twice:              
http://bugs.php.net/fix.php?id=41690&r=submittedtwice
register_globals:             http://bugs.php.net/fix.php?id=41690&r=globals
PHP 3 support discontinued:   http://bugs.php.net/fix.php?id=41690&r=php3
Daylight Savings:             http://bugs.php.net/fix.php?id=41690&r=dst
IIS Stability:                http://bugs.php.net/fix.php?id=41690&r=isapi
Install GNU Sed:              http://bugs.php.net/fix.php?id=41690&r=gnused
Floating point limitations:   http://bugs.php.net/fix.php?id=41690&r=float
No Zend Extensions:           http://bugs.php.net/fix.php?id=41690&r=nozend
MySQL Configuration Error:    http://bugs.php.net/fix.php?id=41690&r=mysqlcfg

Reply via email to