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Date: Sat, 02 May 2026 10:44:56 -0500
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Subject: Re: [PHP-DEV] [RFC] __exists(), a magic method for distinguishing "missing"
 from "set to null"
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From: larry@garfieldtech.com ("Larry Garfield")

On Fri, May 1, 2026, at 4:37 AM, Nicolas Grekas wrote:
> Dear internals,
>
> It's my pleasure to submit this new RFC to yours.
> Please have a look and let me know:
> https://wiki.php.net/rfc/exists-magic-method
>
> TL;DR: I'm proposing a new opt-in magic method:
>
>     public function __exists(string $name): bool;
>
> It'd let userland tell "set to null" apart from "missing" on objects,=20
> it'd restore
> isset() <=3D> ?? equivalence on magic properties, and it'd fixe GH-126=
95=20
> as a
> corollary. It's forward-compatible as a regular method on PHP <=3D 8.5=20
> (probeable
> via method_exists()), and would be magic on 8.6+.
>
> Cheers,
> Nicolas

Thanks for the very detailed RFC!

> If it returns false, the fetch produces =E2=80=9Cuninitialized=E2=80=9D=
 (treated as null by ??, so y is evaluated). __get() is not called.

What is y?  Looks like a reference to a previous iteration of the text.

The Sequencing section also doesn't describe the behavior when __exists(=
) isn't defined.  Does it just skip to step 4?  (Please specify in the t=
ext.)

Is the intent to eventually deprecate __isset()?  The RFC it doesn't now=
, but do you feel that is the eventual end-game, in PHP 10 or whatever?

The big one: Should any parallel changes or additions be made to propert=
y hooks?  An exists() operation in addition to get/set, for instance?  (=
I'm not sure at the moment, but it should be thought through and discuss=
ed, and if not, documented in the RFC.)

--Larry Garfield