php8.1 - Deprecated Functionality: DateTime() - date

Question

We use the following code that worked perfectly on php7.4, but we get a deprecated error on php8.1. But how can we succesfully rewrite this for php8.1?
Error:
Deprecated Functionality: DateTime::__construct(): Passing null to parameter #1 ($datetime) of type string is deprecated
Current code:
$today = new \DateTime();$orderdate = new \DateTime($orders->getCreatedAt());
<?php if($orderdate->diff($today)->days > 14):?>
<?php endif;?>

Answer 1

You can no longer do this:
new \DateTime(null);
In your exact use case, I think that PHP has highlighted a bug in your code. If the order does not have a created at date, you'll populate the variable with the date/time when the script runs, which may not be what you want:
var_dump(new \DateTime('1985-12-31 15:00:00'));
var_dump(new \DateTime(''));
var_dump(new \DateTime(null));
object(DateTime)#1 (3) {
["date"]=>
string(26) "1985-12-31 15:00:00.000000"
["timezone_type"]=>
int(3)
["timezone"]=>
string(16) "Europe/Amsterdam"
}
object(DateTime)#1 (3) {
["date"]=>
string(26) "2022-09-19 12:28:23.003960"
["timezone_type"]=>
int(3)
["timezone"]=>
string(16) "Europe/Amsterdam"
}
Deprecated: DateTime::__construct(): Passing null to parameter #1 ($datetime) of type string is deprecated in /in/67OFM on line 5
object(DateTime)#1 (3) {
["date"]=>
string(26) "2022-09-19 12:28:23.003987"
["timezone_type"]=>
int(3)
["timezone"]=>
string(16) "Europe/Amsterdam"
}
Demo
If you want to use DB information:
$orderdate = $orders->getCreatedAt()
? new \DateTime($orders->getCreatedAt())
: null;
If you want to default to "now", make it explicit so nobody wonders whether it's intentional:
$orderdate = $orders->getCreatedAt()
? new \DateTime($orders->getCreatedAt())
: new \DateTime();
Last but not least... Analyse if it makes sense from the business logic standpoint to have orders with no creation date. What does that mean?