note 125975 added to function.date-diff

This behavior looks really weird to me : // Just take a date, in Paris $date = new DateTime('2021-04-01 01:30', new DateTimeZone('Europe/Paris')); $dateLater = (clone $date); $dateLater = $dateLater->add(new \DateInterval('P3M')); // add literally 3 months ⏰ // ask the difference : var_dump(date_diff($date, $dateLater)); // <= 2 months and 30 days 🤯 Why ? Why is it that if I add 3 months it becomes 2 months and 30 days (in the same timezone) ? ---- Server IP: 45.112.84.4 Probable Submitter: 45.112.85.242 (proxied: 93.176.131.62) ---- Manual Page -- http://php.net/manual/en/function.date-diff.php Edit -- https://master.php.net/note/edit/125975 Del: integrated -- https://master.php.net/note/delete/125975/integrated Del: useless -- https://master.php.net/note/delete/125975/useless Del: bad code -- https://master.php.net/note/delete/125975/bad+code Del: spam -- https://master.php.net/note/delete/125975/spam Del: non-english -- https://master.php.net/note/delete/125975/non-english Del: in docs -- https://master.php.net/note/delete/125975/in+docs Del: other reasons-- https://master.php.net/note/delete/125975 Reject -- https://master.php.net/note/reject/125975 Search -- https://master.php.net/manage/user-notes.php