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Date: Tue, 03 Feb 2026 09:47:31 +0100
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Subject: Re: [PHP-DEV] [RFC] Allow Reassignment of Promoted Readonly Properties in
 Constructor
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From: rob@bottled.codes ("Rob Landers")

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On Mon, Feb 2, 2026, at 22:14, Nicolas Grekas wrote:
> Hi Marco,
>=20
> Le lun. 2 f=C3=A9vr. 2026 =C3=A0 11:54, Marco Pivetta <ocramius@gmail.=
com> a =C3=A9crit :
>> Hey Nicolas,
>>=20
>>=20
>> On Thu, 22 Jan 2026 at 16:34, Nicolas Grekas <nicolas.grekas+php@gmai=
l.com <mailto:nicolas.grekas%2Bphp@gmail.com>> wrote:
>>> Dear all,
>>>=20
>>> Here is a new RFC for you to consider:
>>> https://wiki.php.net/rfc/promoted_readonly_constructor_reassign
>>=20
>>=20
>> What happens if one calls `$obj->__construct(1, 2, 3)` (on an already=
 instantiated `$obj`) in the context of this patch?
>=20
> Thanks for asking, I didn't think about this. This made me also think =
about ReflectionClass::newInstanceWithoutConstructor().
> I clarified this in the RFC, see "Direct __construct() Calls Cannot By=
pass Readonly" and "Reflection: Objects Created Without Constructor".
> Patch and PR updated also if anyone wants to run some code where this =
RFC can be played with.
>=20
> Cheers,
> Nicolas

Hi Nicolas,

Under "Child Classes Can Reassign Parent Properties": this feels like a =
major footgun. Calling parent::__construct() won't allow a reset (per th=
e rules of calling a constructor directly); which would completely break=
 inheritance... but then in the examples it says that calling a construc=
tor directly can reset it -- but you can't?

This feels really inconsistent to me.

=E2=80=94 Rob
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<!DOCTYPE html><html><head><title></title></head><body><div>On Mon, Feb =
2, 2026, at 22:14, Nicolas Grekas wrote:</div><blockquote type=3D"cite" =
id=3D"qt" style=3D""><div dir=3D"ltr"><div dir=3D"ltr">Hi Marco,</div><d=
iv><br></div><div class=3D"qt-gmail_quote qt-gmail_quote_container"><div=
 dir=3D"ltr" class=3D"qt-gmail_attr">Le&nbsp;lun. 2 f=C3=A9vr. 2026 =C3=A0=
&nbsp;11:54, Marco Pivetta &lt;<a href=3D"mailto:ocramius@gmail.com">ocr=
amius@gmail.com</a>&gt; a =C3=A9crit&nbsp;:</div><blockquote class=3D"qt=
-gmail_quote" style=3D"margin-top:0px;margin-right:0px;margin-bottom:0px=
;margin-left:0.8ex;border-left-width:1px;border-left-style:solid;border-=
left-color:rgb(204, 204, 204);padding-left:1ex;"><div dir=3D"ltr"><div d=
ir=3D"ltr"><div>Hey Nicolas,</div><div><br></div></div><div><br></div><d=
iv class=3D"qt-gmail_quote"><div dir=3D"ltr" class=3D"qt-gmail_attr">On =
Thu, 22 Jan 2026 at 16:34, Nicolas Grekas &lt;<a href=3D"mailto:nicolas.=
grekas%2Bphp@gmail.com" target=3D"_blank">nicolas.grekas+php@gmail.com</=
a>&gt; wrote:</div><blockquote class=3D"qt-gmail_quote" style=3D"margin-=
top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left=
-width:1px;border-left-style:solid;border-left-color:rgb(204, 204, 204);=
padding-left:1ex;"><div dir=3D"ltr"><div>Dear all,</div><div><br></div><=
div>Here is a&nbsp;new RFC for you to consider:</div><div><a href=3D"htt=
ps://wiki.php.net/rfc/promoted_readonly_constructor_reassign" target=3D"=
_blank">https://wiki.php.net/rfc/promoted_readonly_constructor_reassign<=
/a></div></div></blockquote><div><br></div><div><div><br></div><div>What=
 happens if one calls `$obj-&gt;__construct(1, 2, 3)` (on an already ins=
tantiated `$obj`) in the context of this patch?</div></div></div></div><=
/blockquote><div><br></div><div>Thanks for asking, I didn't think about =
this. This made me also think about ReflectionClass::newInstanceWithoutC=
onstructor().</div><div>I clarified this in the RFC, see "Direct __const=
ruct() Calls Cannot Bypass Readonly" and "Reflection: Objects Created Wi=
thout Constructor".</div><div>Patch and PR updated also if anyone wants =
to run some code where this RFC can be played with.</div><div><br></div>=
<div>Cheers,</div><div>Nicolas</div></div></div></blockquote><div><br></=
div><div>Hi Nicolas,</div><div><br></div><div>Under "Child Classes Can R=
eassign Parent Properties": this feels like a major footgun. Calling par=
ent::__construct() won't allow a reset (per the rules of calling a const=
ructor directly); which would completely break inheritance... but then i=
n the examples it says that calling a constructor directly can reset it =
-- but you can't?</div><div><br></div><div>This feels really inconsisten=
t to me.</div><div><br></div><div id=3D"sig121229152">=E2=80=94 Rob</div=
></body></html>
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