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Date: Thu, 30 May 2024 16:07:17 +0100 (BST)
To: =?UTF-8?Q?Alexandru_P=C4=83tr=C4=83nescu?= <drealecs@gmail.com>
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Subject: Re: [PHP-DEV] [RFC] Asymmetric Visibility, v2
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From: derick@php.net (Derick Rethans)

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On Thu, 30 May 2024, Alexandru P=C4=83tr=C4=83nescu wrote:

> On Wed, May 29, 2024 at 10:18=E2=80=AFPM Larry Garfield <larry@garfieldte=
ch.com>
> wrote:
>=20
> > As promised, Ilija and I offer this revised version of asymmetric
> > visibility.
> >
> > https://wiki.php.net/rfc/asymmetric-visibility-v2
> >
> >
> Hey Larry, Ilija,
>=20
> I have one concern so far, and it's related to the inheritance section.
>=20
> If in a class I define the property as private,
> I know that there is no way for external scope or extending classes scope
> to read or write to the property.
> (of course, ignoring reading/writing using reflection or re-binded closur=
es)
>=20
> If an extending class defines the property with a wider visibility,
> protected or public, it will shadow the initial one and not change its
> visibility.

private and protected differ here already, even without async=20
visibility:

https://3v4l.org/8Ynog

A protected property does not create a new bag to store data in, which=20
does happen for a private property.

> Now, if I define the property as public private(set) with similar=20
> intentions, to make sure that there is no way for external scope or=20
> extending classes scope to write to the property, while allowing=20
> reading from external scope (or extending classes scope).
>=20
> But the problem is that an extending class can define the property as=20
> public protected(set), and that will easily allow the property that I=20
> wanted to make sure it is private for writing to be changed by an=20
> extending class to be protected.

public private(set) properties aren't really private, so you don't get=20
the shadowing, but you do have a point wrt to the expectation that an=20
inherited class can't easily override the private(set) part (with=20
protected(set) or public(set)).

Hopefully Ilija or Larry can explain :-)

cheers,
Derick
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