On Wednesday, 25 March 2026 at 07:40, Robert Humphries <[email protected]> wrote:
> Good Morning Internals, > > I am aware that traits in general are a topic where people can have > strong opinions, so I wanted to get an idea of initial thoughts on > this before deciding if it is worth looking into any further. > > At the moment, there are three functions in SPL that allow access to > what a given class is using in some way: > * `class_implements` > * `class_parents` > * `class_uses` (returns the traits the current class uses) > > `class_uses` is unique out of the three in that it only returns traits > declared on the current class as opposed to the parent class (and > higher in inheritance). While this is documented in the manual, > looking at the original bug ticket that introduced `class_uses` > (https://bugs.php.net/bug.php?id=55266) then it isn't documented why > it only returns traits on the current class. As far as I can tell from > the bug ticket and the code, `class_implements` was copied for > `class_uses` and while `_zend_class_entry->interaces` contains all > interfaces (including from the parent classes), > `_zend_class_entry->interaces->trait_names` does not. > > So, in terms of my question; what would be the general thoughts on a > new optional argument to `class_uses` that iterates to each parent > class, adding the traits from the parent as well? Frankly I don't like the existence of these 3 functions in SPL. This is very much in Reflection territory, and it should only ever be in Reflection. SPL is already a mess of badly designed "features" trying to cohabitate. The Reflection extension is designed to give you access to do introspection with a well-defined API. But more over I don't even think you addition makes that much sense. Traits are not part of the inheritance hierarchy, that's because the "composition" of traits is effectively just copy and paste. Interfaces are fully inherited onto any child class, so there is no need to iterate through the parents to gather all interfaces. Traits do not work this way, any "prior" use information is not transmitted due to the copy and paste nature of them. The current API doesn't even tell you if used traits also use other traits. I don't even know how it handles trait aliases, or if it even cares about them. And that's not even going through overridden trait methods/props/constants at any stage of the inheritance chain. So I'm very much not convinced about this, nor do I see really the utility of wanting this information? But anyway here is a small snippet that will fetch all used traits: https://3v4l.org/kvQGR Best regards, Gina P. Banyard
