2021/11/25/PHP documentation gripe

Codeblog 2024/11/14 untangling setup calls - mostly just notes to myself 2023/06/04 config classes 2023/05/01 DataPorts redesign 2022/07/21 FutilityCloud process design 2022/08/14 Windows joke I wrote in the late 1900s (on TootCat) 2022/07/21 render-dispatch rubberduckery 2022/07/20 comments on The Home Computer Generation 2022/07/18 layout-event rubberducking 2022/06/24 event-object as output container: the consequences 2022/06/23 event-object as output container: the revision 2022/05/30 more data-class rubberducking 2022/05/20 rubberducking about data classes 2022/01/15 standard CV data format 2021/12/17 The Great Data-Class Restacking 2021/11/25 PHP documentation gripe 2021/11/24 things you can't do in PHP 2021/11/23 PortBank refactoring part 2 2021/11/22 PortBank refactoring part 1 2021/11/08 data objects refactoring 2021/11/05 notes for event-system burndown 2021/07/31 a code mystery 2021/05/31 new PHP wishlist item: first keyword 2021/05/28 a kluge using abstract methods 2021/03/21 PHP wishlist 2020/12/04 (notes) 2020/10/30 (notes) 2020/10/29 (notes) 2020/10/28 (notes) 2020/10/27 (notes: Dovecot on cloud5) 2020/08/29 MediaWiki SpecialPages 2020/08/25 The Plex API 2020/06/12 Ferreteria: thoughts on the Wikcess/flex-data system 2020/04/23 Ferreteria: quick notes on a design issue 2020/04/22 Ferreteria: some thoughts on apps vs. frameworks 2020/02/10 job application (yes, I actually sent this in)

The official PHP documentation says:

Covariance allows a child's method to return a more specific type than the return type of its parent's method. Whereas, contravariance allows a parameter type to be less specific in a child method, than that of its parent.

...and then goes on to note that both are supported in #PHP7.4 (which is what I am using).

However:

abstract class cClass1 {
    abstract function GetIt() : mixed;
}
abstract class cClass2 extends cClass1 {
    abstract function GetIt() : object;
}

PHP Fatal error: Declaration of cClass2::GetIt(): object must be compatible with cClass1::GetIt(): mixed in /home/htnet/site/git/ferreteria/base/tests/php2.php on line 6

...and also...

abstract class cClass1 {
    abstract function SetIt($v);
}
abstract class cClass2 extends cClass1 {
    abstract function SetIt(object $v);
}

PHP Fatal error: Declaration of cClass2::SetIt(object $v) must be compatible with cClass1::SetIt($v) in /home/htnet/site/git/ferreteria/base/tests/php2.php on line 6

So, kinda no.

The examples given in the documentation seem to be only about specificity of object types -- so I should be able to do this:

class cClassA {}
class cClassB extends cClassA {}
abstract class cClass1 {
    abstract function SetIt(cClassA $v);
}
abstract class cClass2 extends cClass1 {
    abstract function SetIt(cClassB $v);
}

...but, umm:

PHP Fatal error: Declaration of cClass2::SetIt(cClassB $v) must be compatible with cClass1::SetIt(cClassA $v) in /home/htnet/site/git/ferreteria/base/tests/php2.php on line 8

Looking at the actual example in the docs:

[in progress]