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Subject: Re: [PHP-DEV] [RFC] Readonly property hooks
Date: Wed, 9 Jul 2025 19:58:36 +0200
In-Reply-To: <D8D4749F-1AF5-46FF-BFAE-A52CDC1B2169@nicksdot.dev>
Cc: Nicolas Grekas <nicolas.grekas+php@gmail.com>,
 Larry Garfield <larry@garfieldtech.com>,
 php internals <internals@lists.php.net>
To: Nick <php@nicksdot.dev>
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From: claude.pache@gmail.com (Claude Pache)


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> Le 9 juil. 2025 =C3=A0 15:17, Nick <php@nicksdot.dev> a =C3=A9crit :
>=20
> Hey Claude,
>=20
>=20
> I hear you, but I still struggle to fully grasp the issue. It=E2=80=99s =
genuinely hard for me to come up with a real-world example that actually =
makes sense.
> Everything I=E2=80=99ve seen so far, including the RFC example and =
what I tried myself (I gave it an honest shot), feels either very =
theoretical or entirely intentional, and thus perfectly logical in its =
outcome.
>=20
> In one of your previous mails you brought up an example that requires =
calling a class method (read: intentionally changing class state), which =
 would result in a non-consistent value being returned when calling the =
same property more than once. I get it. But what if the user wants =
exactly that in their `readonly` class?

Yes, it=E2=80=99s mostly theoretical, but it is good to base language =
design on sound theory.

But here is a potential practical issue. A random user wants to extend a =
class from a third-party library, but they are annoyed that a given =
property is readonly. Now, using a get hook, it is trivial for them to =
cheat and to work around what it perceives as an undue limitation, not =
realising that it may break assumptions made elsewhere in the library.  =
=E2=80=94 Indeed, I don=E2=80=99t trust users and want to protect them =
against themselves.

>=20
> That said I did address your concern here (actual RFC PR branch =
against alternative; PoC):
> =
https://github.com/NickSdot/php-php-src/compare/allow-readonly-hooks...Nic=
kSdot:php-php-src:readonly-hooks-strict
>=20
> Larry and I agree that we don=E2=80=99t want this complexity in the =
current RFC.
> Perhaps this is something for a separate `init` hook RFC?

I think indeed that it is not worth making the current proposal more =
complex, but rather considering whether implementing an init hook =
instead is a reasonable alternative.

Also there is another issue with the use of get hook for lazy =
initialisation (although not specific to readonly): The `??=3D` pattern =
breaks if the property is nullable and you initialise it to `null`. It =
is in fact cumbersome to distinguish between an uninitialised property =
and a property initialised with null.

=E2=80=94Claude=

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<html><head><meta http-equiv=3D"content-type" content=3D"text/html; =
charset=3Dutf-8"></head><body style=3D"overflow-wrap: break-word; =
-webkit-nbsp-mode: space; line-break: after-white-space;"><br =
id=3D"lineBreakAtBeginningOfMessage"><div><br><blockquote =
type=3D"cite"><div>Le 9 juil. 2025 =C3=A0 15:17, Nick =
&lt;php@nicksdot.dev&gt; a =C3=A9crit :</div><br =
class=3D"Apple-interchange-newline"><div><meta http-equiv=3D"content-type"=
 content=3D"text/html; charset=3Dutf-8"><div style=3D"overflow-wrap: =
break-word; -webkit-nbsp-mode: space; line-break: =
after-white-space;">Hey Claude,<div><br><br><div>I hear you, but I still =
struggle to fully grasp the issue. It=E2=80=99s genuinely hard for me to =
come up with a real-world example that actually makes =
sense.</div><div>Everything I=E2=80=99ve seen so far, including the RFC =
example and what I tried myself (I gave it an honest shot), feels either =
very theoretical or entirely intentional, and thus perfectly logical in =
its outcome.</div><div><br></div><div>In one of your previous mails you =
brought up an example that requires calling a class method (read: =
intentionally changing class state), which &nbsp;would result in a =
non-consistent value being returned when calling the same property more =
than once. I get it. But what if the user wants exactly that in their =
`readonly` =
class?</div></div></div></div></blockquote><div><br></div><div>Yes, =
it=E2=80=99s mostly theoretical, but it is good to base language design =
on sound theory.</div><div><br></div><div>But here is a potential =
practical issue. A random user wants to extend a class from a =
third-party library, but they are annoyed that a given property is =
readonly. Now, using a get hook, it is trivial for them to cheat and to =
work around what it perceives as an undue limitation, not realising that =
it may break assumptions made elsewhere in the library. &nbsp;=E2=80=94 =
Indeed, I don=E2=80=99t trust users and want to protect them against =
themselves.</div><div><br></div><blockquote type=3D"cite"><div><div =
style=3D"overflow-wrap: break-word; -webkit-nbsp-mode: space; =
line-break: after-white-space;"><div><div><br></div><div>That said =
I&nbsp;<i>did</i>&nbsp;address your concern here (actual RFC PR branch =
against alternative; PoC):</div><div><a =
href=3D"https://github.com/NickSdot/php-php-src/compare/allow-readonly-hoo=
ks...NickSdot:php-php-src:readonly-hooks-strict">https://github.com/NickSd=
ot/php-php-src/compare/allow-readonly-hooks...NickSdot:php-php-src:readonl=
y-hooks-strict</a></div><div><br></div><div>Larry and I agree that we =
don=E2=80=99t want this complexity in the current RFC.</div><div>Perhaps =
this is something for a separate `init` hook =
RFC?</div></div></div></div></blockquote><div><br></div></div>I think =
indeed that it is not worth making the current proposal more complex, =
but rather considering whether implementing an init hook instead is a =
reasonable alternative.<div><br></div><div>Also there is another issue =
with the use of get hook for lazy initialisation (although not specific =
to readonly): The `??=3D` pattern breaks if the property is nullable and =
you initialise it to `null`. It is in fact cumbersome to distinguish =
between an uninitialised property and a property initialised with =
null.</div><div><br></div><div>=E2=80=94Claude</div></body></html>=

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