ID: 45301
Comment by: payton2558 at googlemail dot com
Reported By: payton2558 at googlemail dot com
Status: Open
Bug Type: Unknown/Other Function
Operating System: Windows XP 32, Vista 32
PHP Version: 5.2.6
New Comment:
Here's the shortest version. Try varying the array_fill num parameter.
Lower numbers appear to increase the randomness.
Appears problem is array_rand interfering with the random seed but
please investigate further than that as I'm certain I experienced this
problem before ever using array_rand (rand(0,count($a)-1) works in its
place and doesn't trigger bug in this example).
<?php
$a = array_fill(0, 100000, "word");
for ($i=0; $i<20; $i++) {
array_rand($a);
echo rand(1,9999)."\n";
}
?>
Previous Comments:
------------------------------------------------------------------------
[2008-06-18 18:06:09] sv4php at fmethod dot com
Confirmed on Apache 2.2, Windows XP SP2 with PHP 5.2.6.
Confirmed also without building files (just building the array directly
in a loop).
Requires Windows, doesn't seem to affect mt_rand();
------------------------------------------------------------------------
[2008-06-18 16:20:47] [EMAIL PROTECTED]
On a related note: #45184
------------------------------------------------------------------------
[2008-06-18 16:05:00] payton2558 at googlemail dot com
Description:
------------
The reproduce code demonstrates the bug. You can modify the code in
different ways to affect the severity of the output.
Appears to require Windows.
Please note I have tested on 2 different machines and 3 versions of
php. I have also confirmed this with a couple of users on IRC.
mt_rand may also be affected but not as badly
Unrelated: bugs.php your CAPTCHA system is the worst I could ever
expect for a programming related group
Reproduce code:
---------------
<?php
function RandomNumber() {
$word1 = file('word1.txt'); // word1 and word2.txt can be made by
fwriting "word\n" 50000 times. Different filesizes affect bug.
$word2 = file('word2.txt');
$rword1 = trim($word1[array_rand($word1)]);
$rword2 = trim($word2[array_rand($word2)]);
$rnum = rand(1,999);
return $rnum;
}
for ($i=0; $i<20; $i++) {
echo RandomNumber()."\n";
}
?>
Expected result:
----------------
20 random looking numbers
Actual result:
--------------
20 identical numbers or in other cases, severely unrandom numbers
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=45301&edit=1
