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Bug #80308 strtotime() issue with Nov 1st
Submitted: 2020-11-02 22:45 UTC Modified: 2020-11-02 23:17 UTC
From: bruno at leveque dot io Assigned:
Status: Not a bug Package: *General Issues
PHP Version: 7.4.12 OS: Ubuntu 20.04.1 LTS
Private report: No CVE-ID: None
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 [2020-11-02 22:45 UTC] bruno at leveque dot io 
Description:
------------
strtotime() is encountering issues when dealing with Nov 1st, 2020 specifically.

- Adding 2 x 86400 seconds to Nov 1st will actually return Nov 2nd
- Adding '+2 days' to the same date returns Nov 3rd

This issue does not happen with any other date.

Test script:
---------------
<?php

/* Add 2 days to Oct 1st
** Outputs 2020-10-03 - Correct
*/
echo strftime('%Y-%m-%d', strtotime('2020-10-01') + (2 * 86400))."\n";

/* Add 2 days to Nov 1st
** Outputs 2020-11-02 - Bug
*/
echo strftime('%Y-%m-%d', strtotime('2020-11-01') + (2 * 86400))."\n";

/* Add 2 days to Nov 1st
** Outputs 2020-11-03 - Correct
*/
echo strftime('%Y-%m-%d', strtotime('2020-11-01 + 2 days'))."\n";

Expected result:
----------------
2020-10-03
2020-11-03
2020-11-03

Actual result:
--------------
2020-10-03
2020-11-02
2020-11-03

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 [2020-11-02 22:47 UTC] requinix@php.net
-Status: Open +Status: Not a bug
 [2020-11-02 22:47 UTC] requinix@php.net 
Apparently you're in one of the timezones where 2020-11-01 was more than 86400 seconds long.
 [2020-11-02 22:56 UTC] bruno at leveque dot io 
I understand that the Daytime Savings Time change could be at play however why wouldn't this apply to '+2 days' as well?.
 [2020-11-02 23:17 UTC] requinix@php.net 
+2 days means literally +2 days, and 11-01 + 2 days = 11-03. The length of those days has no bearing on (this) math.
 [2020-11-03 01:09 UTC] safa_al18 at hotmail dot com 
i asked this issue from
https://stackoverflow.com/questions/64655031/php-says-everyday-have-diffrent-seconds-for-time-zone
some users says 
"We changed from daylight time to standard time on November 1. There was an extra hour that morning. "
thats great php calculated this.
 
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