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Date: Thu, 03 Jul 2025 16:38:58 -0500
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Subject: Re: [PHP-DEV] [RFC idea] Target-aware attributes
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From: larry@garfieldtech.com ("Larry Garfield")

On Thu, Jul 3, 2025, at 12:54 PM, Andreas Hennings wrote:


>> > A setter method injection is what I did in AttributeUtils, because it was the only real option.  Alternatively, I suppose core could use property setter injection (either a magically named property like $__reflector, or a property that itself has an attribute on it, etc.).  That would allow it to be set before the constructor is called, and with property hooks would allow processing either immediately or later in the constructor.  The downside here is that Attribute are, generally, serializable, but a Reflection object is not.  So if someone wanted a serializable attribute they would have to accept the property, use it, and then remember to unset it at some point.  That's clumsy.
>> >
>> > --Larry Garfield
>> >
>>
>> As someone that's written yet another userland "solution" for this problem, I have an alternative solution, based somewhat on an internalised  concept of "never store Reflectors".
>>
>> Introduce an interface "ReflectorAttribute" (bike shedding to come); which accepts a single Reflector argument.
>>
>> If the attribute implements the interface, the method is called immediately following instantiation.
>
> Yep, this is the "method injection" mentioned by Larry, or what I
> referred to as "setter injection".
> I have not seen your library, but I assume that's where it is going.

Yes, that is what AttributeUtils does today, almost exactly.  From the docs:

#[\Attribute]
class AttribWithName implements FromReflectionClass 
{
    public readonly string $name;
    
    public function __construct(?string $name = null) 
    {
        if ($name) {
            $this->name = $name;
        }
    }
    
    public function fromReflection(\ReflectionClass $subject): void
    {
        $this->name ??= $subject->getShortName();
    }
}

(There's a different interface for each type of thing an attribute can be put on because the parameter type is different.)

--Larry Garfield