Bug #62193 [Nab]: strtotime returning wrong month

Edit report at https://bugs.php.net/bug.php?id=62193&edit=1 ID: 62193 Updated by: rasmus@php.net Reported by: thomasrothwell dot 1990 at gmail dot com Summary: strtotime returning wrong month Status: Not a bug Type: Bug Package: Date/time related Operating System: Ubuntu 12.04 LTS & Ubuntu 10.04 PHP Version: 5.3Git-2012-05-31 (Git) Block user comment: N Private report: N New Comment: This is standard UNIX behaviour. You need to be explicit as you discovered. Try the same thing in a shell script, for example: $ date Fri May 31 16:37:45 PDT 2013 $ date --date='+1 month' +'Next month is %B' Next month is July SQLite and many other tools you will come across follow this same standard behaviour when it comes to data manipulation. It is described by GNU here: http://www.gnu.org/software/tar/manual/html_node/Relative-items-in-date- strings.html#SEC120 There is really no good answer to this one. We can't just assume the 1st of the month, because then adding 1 day would be equivalent to adding 1 month on the last day of the month. That's a huge amount of data loss. So we follow the UNIX/GNU convention. Previous Comments: ------------------------------------------------------------------------ [2013-05-31 19:37:22] phpbugs at thehiltons dot net How this is an overflow issue: $timeStr = strtotime('Jun'); // just 'Jun' $date = getdate($timeStr); The date represented by $date should be in June, but it's not. Since I didn't specify a day it shouldn't be an overflow issue. If the day is assumed/implied by the current day then that should be documented. I would argue that since it is not specified, the 1st of the month at 0:00:00 is the safest assumption. ------------------------------------------------------------------------ [2013-05-31 18:10:57] aharvey@php.net Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php PHP date functions will overflow out of bound values: since June 31 doesn't exist, it becomes July 1. ------------------------------------------------------------------------ [2013-05-31 15:29:50] phpbugs at theHiltons dot net Reproduced May 31st, 2013, CentOS 64Bit, PHP 5.4.15: foreach (['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'] as $monthName) { echo "getdate(strtotime('$monthName'))['month'] = " . getdate(strtotime($monthName))['month'] . "\n"; echo "getdate(strtotime('$monthName'))['mon'] = " . getdate(strtotime($monthName))['mon'] . "\n"; } ------------------------------------------------------------------------ [2012-05-31 02:25:24] thomasrothwell dot 1990 at gmail dot com Assuming the issue is related to June only having 30 days, which then pushes it to the next month July. <?php 2 //Expected 30/06 3 echo date('d/m', strtotime('+1 MONTH')); 4 //Result 01/07 5 6 //Expected 30/06 7 echo gmdate('d/m', strtotime('+1 MONTH')); 8 //Result 01/07 9 10 //Expected 01/06 11 echo date('d/m', strtotime('first day of +1 month')); 12 //Result 01/06 Could be safe to assume that the function should check the limits of each month to prevent it from going past the extreme. ------------------------------------------------------------------------ [2012-05-31 02:10:51] thomasrothwell dot 1990 at gmail dot com Description: ------------ Came across the wrong month being returned when using the following: <?php echo date('m', strtotime('+1 MONTH')); ?> Expected: 06 Result: 07 I've only noticed this occur Today (31st of May 2012). Altered my php.ini to use the following config as well: date.timezone = "Australia/Sydney" date.default_latitude = -35.308142 date.default_longitude = 149.124518 Thinking it could be a timezone issue. Also attempted use of gmdate. What I found to work was: <?php echo date('m', strtotime('first day of +1 month')); ?> Expected: 06 Result: 06 Test script: --------------- <?php //Expected 06 echo date('m', strtotime('+1 MONTH')); //Result 07 //Expected 06 echo gmdate('m', strtotime('+1 MONTH')); //Result 07 //Expected 06 echo date('m', strtotime('first day of +1 month')); //Result 06 Expected result: ---------------- 060606 Actual result: -------------- 070706 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=62193&edit=1