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Date: Tue, 09 May 2023 22:59:43 +0000
To: "php internals" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Property hooks, nee accessors
From: larry@garfieldtech.com ("Larry Garfield")

On Tue, May 9, 2023, at 5:46 PM, Larry Garfield wrote:


>> I have a bigger concern: the take on references contradicts with the intro
>> about BC breaks: turning a materialized property into virtual one would
>> break BC as far as refs are concerned. One idea to fix that: add a ref
>> hook, that must return a reference. If not implemented => Error when trying
>> to get-by-ref. This could also help solve the $foo->array[] case (including
>> the asym-visiblity issue).
>
> That might be possible.  The issue there is that the returned ref would 
> still be bypassing the get/set hooks, so you're just adding a way to 
> dance around the existing hook implementations, which is exactly what 
> we're trying to avoid.  Also, what would that hook even mean if used on 
> a virtual property?
>
> Moreover, in practice, getting a reference to a property is extremely 
> rare, with the exception of array writes.  I cannot recall the last 
> time I even saw some code get a reference to a property.  That's why we 
> felt comfortable just leaving it at is.  In an earlier version of the 
> RFC we had a way for properties to just disable references without 
> adding any hooks, but removed it on the grounds that it was not worth 
> the effort.

Addendum here: The RFC wasn't clear, in part because I wasn't clear, but the prohibition on [] on properties applies only on set.  On get, whatever array value is returned from the hook is just a boring array, which can then be dereferenced to look up a key.

I've updated the RFC accordingly to make it clearer what is and isn't allowed with arrays.

--Larry Garfield