Description:
------------
---
From manual page: https://php.net/function.date-default-timezone-set
---
The documentation contains
"
    Note:

    Since PHP 5.1.0 (when the date/time functions were rewritten), every call to a date/time function will generate a E_NOTICE if the timezone isn't valid, and/or a E_WARNING message if using the system settings or the TZ environment variable.
"
However, I don't have any warning issued when I run the function date without timezone on Debian 9.7.

root@StretchDevNewLaurent:/home/web/teliway.com/appli# 
  grep -r 'date.timezone' /etc/php/7.0/
/etc/php/7.0/apache2/php.ini:; http://php.net/date.timezone
/etc/php/7.0/apache2/php.ini:;date.timezone =
/etc/php/7.0/phpdbg/php.ini:; http://php.net/date.timezone
/etc/php/7.0/phpdbg/php.ini:;date.timezone =
/etc/php/7.0/cli/php.ini:; http://php.net/date.timezone
/etc/php/7.0/cli/php.ini:;date.timezone =




Test script:
---------------
<?php
echo date('Ymd');
1/0;
?>
20190606PHP Warning:  Division by zero in - on line 3
PHP Stack trace:
PHP   1. {main}() -:0

Warning: Division by zero in - on line 3

Call Stack:
   21.1228     344160   1. {main}() -:0