1--TEST-- 2Bug #75167 (DateTime::add does only care about backward DST transition, not forward) 3--FILE-- 4<?php 5$tz = new DateTimeZone('Europe/London'); // A timezone that has DST 6 7$five_hours_interval = new DateInterval('PT5H'); 8 9$date = new DateTime("2014-3-30 00:00:00", $tz); 10 11// Add five hours and subtract 5 hours. The $newDate should then equal the date. 12$five_hours_later = (clone $date)->add($five_hours_interval); 13$newDate = (clone $five_hours_later)->sub($five_hours_interval); 14 15echo $date->format('c') . "\n"; 16echo $newDate->format('c'); 17?> 18--EXPECT-- 192014-03-30T00:00:00+00:00 202014-03-30T00:00:00+00:00 21