2021/07/31/a code mystery

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)

Part 1

namespace ferret\data\bank;

[...]

class cIOUnitSimple extends cIOUnit {

Part 2

namespace ferret\data;
use ferret\data\bank\cIOUnit;
use ferret\data\bank\cIOUnitSimple;

[...]

$sClass = $this->DefaultIOUnitClass();
if (is_a($sClass,cIOUnit::class)) {
    // create new I/O Unit object
    $oIOUnit = new $sClass($this,$ouNative);
} else {
    $s = "Default IOUnit class is [$sClass], which is not a cIOUnit.";
    $e = new \ferret\except\cInternal($s);
    throw $e;
}

Part 3 - output

Internal ferret panic: Default IOUnit class is [ferret\data\bank\cIOUnitSimple], which is not a cIOUnit.

Conundrum

It doesn't make sense, because the default IOUnit class retrieved (into $sClass, in part 2), ferret\data\bank\cIOUnitSimple, is in fact directly descended from ferret\data\bank\cIOUnit (in part 1). I can only think I'm reading the definition of is_a() wrong somehow.

Tenatatively: is_a() is messed up; use is_subclass_of() instead.