No Max() On Empty Array
max() does not accept an empty array as argument. In that case, it used to return NULL, but NULL is also a valid return value, and it is not possible to differentiate between the NULL of an empty array and the NULL that is really a maximum value.
PHP code
<?php
max([]);
?>
Before
PHP Warning: max(): Array must contain at least one element
Warning: max(): Array must contain at least one element
After
PHP Fatal error: Uncaught ValueError: max(): Argument #1 ($value) must contain at least one element
Fatal error: Uncaught ValueError: max(): Argument #1 ($value) must contain at least one element
PHP version change
This behavior changed in 8.0.