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Bug #26009 mktime calc fails on specific dates
Submitted: 2003-10-27 14:43 UTC Modified: 2003-10-28 11:47 UTC
From: nic at nicskitt dot co dot uk Assigned:
Status: Not a bug Package: Date/time related
PHP Version: 4.3.3 OS: Windows XP Pro SP1, IIS, ISAPI
Private report: No CVE-ID: None
 [2003-10-27 14:43 UTC] nic at nicskitt dot co dot uk
Description:
------------
When performing the while loop shown in the code mktime function produces duplicate results on the following specific dates (2004-03-27) and (2003-03-29) and (2002-03-30). They all seem to be in the month of march. This starts afer 2001 and I havent yet checked how far it continues.

Because mktime is suppose to handle illegal days and therefore recalcuate the whole date I cant see why this would happen.



Reproduce code:
---------------
$starting = strtotime("2001-01-01");
$ending = strtotime("2005-01-01");
$newdate = $starting;
$day 	= date("d",$newdate);
$month 	= date("m",$newdate);
$year 	= date("Y",$newdate);

echo("Starting->".date("Y-m-d",$newdate)."<br>");
echo("Ending->".date("Y-m-d",$ending)."<br>");
$x = 0;
while($newdate<$ending){

	$newdate = mktime(0,0,0,$month,($day+$x),$year);
	$fulldate = date("Y-m-d",$newdate);
	echo($fulldate."<br>");
	$x ++;	
}

Expected result:
----------------
Relevant Areas...

2002-03-29
2002-03-30 <- just one as you would expect
2002-04-01
2002-04-02
2002-04-03
...skip output...
2003-03-27
2003-03-28
2003-03-29 <- Just one as you would expect
2003-03-31
2003-04-01

and so on...

Actual result:
--------------
Relevant Areas...

2002-03-28
2002-03-29
2002-03-30 
2002-03-30 <- Duplicate Date
2002-04-01
2002-04-02
...skip output...
2003-03-27
2003-03-28
2003-03-29
2003-03-29 <- Duplicate Date
2003-03-31
2003-04-01

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 [2003-10-28 11:47 UTC] sniper@php.net
We are happy to tell you that you just discovered Daylight Savings
Time. For more information see:
http://webexhibits.org/daylightsaving/b.html
Instead of using mktime/date consider using gmmktime and gmdate which do
not suffer from DST.

..
 
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