Bug #52480 [Csd]: Incorrect difference using DateInterval

Edit report at https://bugs.php.net/bug.php?id=52480&edit=1 ID: 52480 Updated by: requinix@php.net Reported by: alex dot joyce at staff dot comcen dot com dot au Summary: Incorrect difference using DateInterval Status: Closed Type: Bug Package: Date/time related Operating System: Debian 5.0.3 PHP Version: 5.3.3 Assigned To: derick Block user comment: N Private report: N New Comment: Happens for March https://3v4l.org/R3LLN but not May https://3v4l.org/nblYg. DST? Previous Comments: ------------------------------------------------------------------------ [2017-03-20 11:22:55] tomasz dot majerski at o2 dot pl Don't close this issue. PHP 7.0.6 still not getting expected results... $date_start = '2017-03-01'; $date_end = '2017-03-31'; DateInterval Object ( [y] => 0 [m] => 1 [d] => 2 [h] => 0 [i] => 0 [s] => 0 [weekday] => 0 [weekday_behavior] => 0 [first_last_day_of] => 0 [invert] => 0 [days] => 30 [special_type] => 0 [special_amount] => 0 [have_weekday_relative] => 0 [have_special_relative] => 0 ) ------------------------------------------------------------------------ [2017-03-19 09:58:41] heiglandreas@php.net This seems to be fixed in supported versions of PHP. Therefore I'm closing this issue. php > $date_start = new DateTime('2010-03-01'); php > $date_end = new DateTime('2010-07-29'); php > php > $interval = $date_start->diff($date_end); php > php > print_r($interval); DateInterval Object ( [y] => 0 [m] => 4 [d] => 28 [h] => 0 [i] => 0 [s] => 0 [f] => 0 [weekday] => 0 [weekday_behavior] => 0 [first_last_day_of] => 0 [invert] => 0 [days] => 150 [special_type] => 0 [special_amount] => 0 [have_weekday_relative] => 0 [have_special_relative] => 0 ) ------------------------------------------------------------------------ [2016-11-23 07:14:51] lebeker at gmail dot com Still got a problems: (new DateTime('2016-10-01'))->diff((new DateTime('2016-10-31'))) // 1 month (new DateTime('2016-11-01'))->diff((new DateTime('2016-11-30'))) // 29 days either first should be 30 days, or the second one 1 month (new DateTime('2016-11-01'))->diff((new DateTime('2016-12-01'))) // 30 days but that's definitely 1 whole month and what's more interesting (new DateTime('2016-11-01'))->diff((new DateTime('2016-11-31'))) // 30 days but there is no such date as '2016-11-31', but that's probably another bug. PHP 7.0.8-0ubuntu0.16.04.3 ------------------------------------------------------------------------ [2016-02-12 01:56:26] pinballfan at outlook dot com After trying Marcel's code I got the same 'problem' on PHP 5.6 on a 64bit Windows 10 machine. However unexpected the result, I believe it is consistent with how PHP's datetime rounds dates around. Using this example: $date1 = new DateTime('2011-08-31T00:00:00Z'); $date2 = new DateTime('2012-03-01T00:00:00Z'); $interval = $date1->diff($date2); var_dump($interval); $interval->m = 5 $interval->d = 30 The expectation might be 6 months and 1 day What I'm guessing might be happening is that PHP starts adding 1 month like so: 2011-08-31 = starting date 2011-09-31 = starting date + 1 month (but there is no such thing as sept 31!) 2011-10-01 = date now wraps around to 2011-10-01 since 2011-09-31 doesn't exist 2011-11-01 = + 1 month (2 total) 2011-12-01 = + 1 month (3 total) 2012-01-01 = + 1 month (4 total) 2012-02-01 = + 1 month (5 total) 2012-03-01 = When diff'ing PHP does NOT include the final date maybe like DatePeriod. So that could be how it arrived at 5m and 30d ------------------------------------------------------------------------ [2015-01-12 09:43:52] marcel at berteler dot co dot za I experience the same issue where the month is incorrectly calculated: $Dob = new DateTime(); $Dob->setDate(2011, 8, 31); $Dob->setTime(0,0,0); $VisitDate = new DateTime(); $VisitDate->setDate(2012, 03, 01); $VisitDate->setTime(0,0,0); $interval = $Dob->diff($VisitDate); echo $interval->m; echo $interval->d; Should return 6 & 1 but returns 5 & 30. Changing the timezones still returns unexpected results: $Dob = new DateTime(); $Dob->setTimezone(new DateTimeZone('UTC')); $Dob->setDate(2011, 8, 30); $Dob->setTime(0,0,0); $VisitDate = new DateTime(); $VisitDate->setTimezone(new DateTimeZone('UTC')); $VisitDate->setDate(2012, 2, 1); $VisitDate->setTime(0,0,0); $interval = $Dob->diff($VisitDate); echo $interval->m; (returns 5) echo $interval->d; (return 2) 2011-08-30 to 2012-03-01 return 6 months and 0 days. Tried it in on both a Linux and Windows server and same result. ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=52480 -- Edit this bug report at https://bugs.php.net/bug.php?id=52480&edit=1