Possible bug on PHP DateTime modify method-CodePudding

I'm tring to get a list of dates and hours from one date to another.

To do that I'm using DateTime class and modify method to add 1 hour to the current dateTime. But something weird happens, the 02 hour of the 2022/03/27 (year/month/day) is not calculated.

Here's the test code (not the real code):

<?php
$from = new DateTime(date('2022/03/27 00:00:00'));
$to = new DateTime(date('2022/03/27 23:59:59'));

do {
  echo $from->format('Y/m/d H') . "\n";
  $from->modify('  1 hour');
} while ($from->getTimestamp() < $to->getTimestamp());

And that's the results:

2022/03/27 00
2022/03/27 01
2022/03/27 03
2022/03/27 04
2022/03/27 05
2022/03/27 06
2022/03/27 07
2022/03/27 08
2022/03/27 09
2022/03/27 10
2022/03/27 11
2022/03/27 12
2022/03/27 13
2022/03/27 14
2022/03/27 15
2022/03/27 16
2022/03/27 17
2022/03/27 18
2022/03/27 19
2022/03/27 20
2022/03/27 21
2022/03/27 22
2022/03/27 23

Where is the "2022/03/27 02" ?

I'm using:

PHP 7.4.30 (cli) (built: Jun 27 2022 08:11:59)

Thanks.

CodePudding user response：

This seems to be because Daylight Savings Time comes into play at 2am on March 27th in your time zone.

$from = new DateTime(date('2022/03/27 00:00:00'));
$to = new DateTime(date('2022/03/27 23:59:59'));

do {
  echo $from->format('Y/m/d H:i:s I') . "\n"; // with DST indicator
  $from->modify('  1 hour');
  } while ($from->getTimestamp() < $to->getTimestamp());

produces

2022/03/27 00:00:00 0
2022/03/27 01:00:00 0
2022/03/27 03:00:00 1
2022/03/27 04:00:00 1
2022/03/27 05:00:00 1
2022/03/27 06:00:00 1
2022/03/27 07:00:00 1
2022/03/27 08:00:00 1
2022/03/27 09:00:00 1
2022/03/27 10:00:00 1
2022/03/27 11:00:00 1
2022/03/27 12:00:00 1
2022/03/27 13:00:00 1
2022/03/27 14:00:00 1
2022/03/27 15:00:00 1
2022/03/27 16:00:00 1
2022/03/27 17:00:00 1
2022/03/27 18:00:00 1
2022/03/27 19:00:00 1
2022/03/27 20:00:00 1
2022/03/27 21:00:00 1
2022/03/27 22:00:00 1
2022/03/27 23:00:00 1

CodePudding user response：

Thanks to @droopsnoot for the DST detail ;)

This code works fine:

<?php

$from = new DateTime(date('2022/03/30 00:00:00'), new DateTimeZone('UTC'));
$to = new DateTime(date('2022/03/30 23:59:59'), new DateTimeZone('UTC'));

do {
  echo $from->format('Y/m/d H') . "\n";
  $from->modify('  1 hour');
} while ($from->getTimestamp() < $to->getTimestamp());