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Date: Sat, 2 May 2026 22:17:31 +0200
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Subject: Re: [PHP-DEV] [RFC] __exists(), a magic method for distinguishing
 "missing" from "set to null"
To: Larry Garfield <larry@garfieldtech.com>
Cc: php internals <internals@lists.php.net>
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From: nicolas.grekas+php@gmail.com (Nicolas Grekas)

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Hi Larry,

Le sam. 2 mai 2026 =C3=A0 17:47, Larry Garfield <larry@garfieldtech.com> a
=C3=A9crit :

> 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,
> > it'd restore
> > isset() <=3D> ?? equivalence on magic properties, and it'd fixe GH-1269=
5
> > as a
> > corollary. It's forward-compatible as a regular method on PHP <=3D 8.5
> > (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 text=
.)
>
> 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 property
> 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 discussed, a=
nd
> if not, documented in the RFC.)


 Thanks for having a look!

I made some changes to clarify, see:
https://wiki.php.net/rfc/exists-magic-method?do=3Ddiff&rev2%5B0%5D=3D177762=
7745&rev2%5B1%5D=3D1777752909&difftype=3Dsidebyside

y =3D> $y
I added a description of the current sequencing of magic methods.
About deprecating __isset, I think it's way too early to consider doing it
for real. Still my answer is yes, but not on any timescale I can
anticipate. I added words about the doc, which should now encourage
__exists IMHO.
About hooks, that deserves a separate RFC to me. I've no intuition on this
as I don't use hooks often enough to feel the need for any missing "exists"
hook. If you still want my noob take on this: a hooked property exists -
because it has hooks. Not super helpful :D I added some words about this in
the RFC.

Cheers,
Nicolas

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<div dir=3D"ltr"><div dir=3D"ltr">Hi Larry,</div><br><div class=3D"gmail_qu=
ote gmail_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">Le=C2=A0sa=
m. 2 mai 2026 =C3=A0=C2=A017:47, Larry Garfield &lt;<a href=3D"mailto:larry=
@garfieldtech.com">larry@garfieldtech.com</a>&gt; a =C3=A9crit=C2=A0:<br></=
div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;bor=
der-left:1px solid rgb(204,204,204);padding-left:1ex">On Fri, May 1, 2026, =
at 4:37 AM, Nicolas Grekas wrote:<br>
&gt; Dear internals,<br>
&gt;<br>
&gt; It&#39;s my pleasure to submit this new RFC to yours.<br>
&gt; Please have a look and let me know:<br>
&gt; <a href=3D"https://wiki.php.net/rfc/exists-magic-method" rel=3D"norefe=
rrer" target=3D"_blank">https://wiki.php.net/rfc/exists-magic-method</a><br=
>
&gt;<br>
&gt; TL;DR: I&#39;m proposing a new opt-in magic method:<br>
&gt;<br>
&gt;=C2=A0 =C2=A0 =C2=A0public function __exists(string $name): bool;<br>
&gt;<br>
&gt; It&#39;d let userland tell &quot;set to null&quot; apart from &quot;mi=
ssing&quot; on objects, <br>
&gt; it&#39;d restore<br>
&gt; isset() &lt;=3D&gt; ?? equivalence on magic properties, and it&#39;d f=
ixe GH-12695 <br>
&gt; as a<br>
&gt; corollary. It&#39;s forward-compatible as a regular method on PHP &lt;=
=3D 8.5 <br>
&gt; (probeable<br>
&gt; via method_exists()), and would be magic on 8.6+.<br>
&gt;<br>
&gt; Cheers,<br>
&gt; Nicolas<br>
<br>
Thanks for the very detailed RFC!<br>
<br>
&gt; 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.<br>
<br>
What is y?=C2=A0 Looks like a reference to a previous iteration of the text=
.<br>
<br>
The Sequencing section also doesn&#39;t describe the behavior when __exists=
() isn&#39;t defined.=C2=A0 Does it just skip to step 4?=C2=A0 (Please spec=
ify in the text.)<br>
<br>
Is the intent to eventually deprecate __isset()?=C2=A0 The RFC it doesn&#39=
;t now, but do you feel that is the eventual end-game, in PHP 10 or whateve=
r?<br>
<br>
The big one: Should any parallel changes or additions be made to property h=
ooks?=C2=A0 An exists() operation in addition to get/set, for instance?=C2=
=A0 (I&#39;m not sure at the moment, but it should be thought through and d=
iscussed, and if not, documented in the RFC.)</blockquote><div><br></div><d=
iv>=C2=A0Thanks for having a look!</div><div><br></div><div>I made some cha=
nges to clarify, see:</div><div><a href=3D"https://wiki.php.net/rfc/exists-=
magic-method?do=3Ddiff&amp;rev2%5B0%5D=3D1777627745&amp;rev2%5B1%5D=3D17777=
52909&amp;difftype=3Dsidebyside">https://wiki.php.net/rfc/exists-magic-meth=
od?do=3Ddiff&amp;rev2%5B0%5D=3D1777627745&amp;rev2%5B1%5D=3D1777752909&amp;=
difftype=3Dsidebyside</a></div><div><br></div><div>y =3D&gt; $y</div><div>I=
 added a description of the current sequencing of magic methods.</div><div>=
About deprecating __isset, I think it&#39;s way too early to consider doing=
 it for real. Still my answer=C2=A0is yes, but not on any timescale I can a=
nticipate. I added words about the doc, which should now encourage __exists=
 IMHO.</div><div>About hooks, that deserves a separate RFC to me. I&#39;ve =
no intuition on this as I don&#39;t use hooks often enough to feel the need=
 for any missing &quot;exists&quot; hook. If you still want my noob take on=
 this: a hooked property exists - because it has hooks. Not super helpful :=
D I added some words about this in the RFC.</div><div><br></div><div>Cheers=
,</div><div>Nicolas</div></div></div>

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