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Date: Thu, 22 May 2025 20:01:17 +0500
Message-ID: <CAJWOiuNbickoi013sGP56V-OiD7zF+gZuaYO5B4=9tsQFavpkA@mail.gmail.com>
Subject: [PHP-DEV] [RFC] Readonly constructors
To: PHP internals <internals@lists.php.net>
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From: 91liahim@gmail.com (Mihail Liahimov)

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In PHP 8.1 the class read-on syntax was added, which allows you to create
classes that are completely closed to changes. In addition, it allows you
to write less boilerplate when declaring a property in the constructor.

Before 8.1:

class A
{
    public function __construct(
        private readonly int $a,
        private readonly int $b,
        private readonly int $c,
    ) { }
}

After 8.1:

readonly class A
{
    public function __construct(
        private int $a,
        private int $b,
        private int $c,
    ) { }
}

But there are also scenarios where, for some reason, not all properties
need to be readonly. For example, when we inherit from a non-readonly class
or when our class has a state for some kind of memoization. In this case,
the class is not readonly, and as a result, you have to write an extra
boiler plate in the constructor. I would like to be able to declare many
readon properties in the constructor in a way similar to readon classes.

I suggest adding the ability to declare a constructor as a readonly. In
this case, all the properties declared in it will be automatically readonly.

class A extends NonReadonlyClass
{
    public readonly function __construct(
        private int $a,
        private int $b,
        private int $c,
    ) { }
}

Yes, it looks a bit strange, but maybe someone will have other suggestions.
Perhaps there is a more competent way to organize this idea.

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<div dir=3D"ltr">In PHP 8.1 the class read-on syntax was added, which allow=
s you to create classes that are completely closed to changes. In addition,=
 it allows you to write less boilerplate when declaring a property in the c=
onstructor.<br><br>Before 8.1:<br><br>class A<br>{<br>=C2=A0 =C2=A0 public =
function __construct(<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 private readonly int $=
a,<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 private readonly int $b,<br>=C2=A0 =C2=A0=
 =C2=A0 =C2=A0 private readonly int $c,<br>=C2=A0 =C2=A0 ) { }<br>}<br><br>=
After 8.1:<br><br>readonly class A<br>{<br>=C2=A0 =C2=A0 public function __=
construct(<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 private int $a,<br>=C2=A0 =C2=A0 =
=C2=A0 =C2=A0 private int $b,<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 private int $c=
,<br>=C2=A0 =C2=A0 ) { }<br>}<br><br>But there are also scenarios where, fo=
r some reason, not all properties need to be readonly. For example, when we=
 inherit from a non-readonly class or when our class has a state for some k=
ind of memoization. In this case, the class is not readonly, and as a resul=
t, you have to write an extra boiler plate in the constructor. I would like=
 to be able to declare many readon properties in the constructor in a way s=
imilar to readon classes.<br><br>I suggest adding the ability to declare a =
constructor as a readonly. In this case, all the properties declared in it =
will be automatically readonly.<br><br>class A extends NonReadonlyClass<br>=
{<br>=C2=A0 =C2=A0 public readonly function __construct(<br>=C2=A0 =C2=A0 =
=C2=A0 =C2=A0 private int $a,<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 private int $b=
,<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 private int $c,<br>=C2=A0 =C2=A0 ) { }<br>=
}<br><br>Yes, it looks a bit strange, but maybe someone will have other sug=
gestions. Perhaps there is a more competent way to organize this idea.</div=
>

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