Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:118411
MIME-Version: 1.0
References: <ec4bc6e5-39ac-4a36-9d63-cca8dc6a29a6@www.fastmail.com>
In-Reply-To: <ec4bc6e5-39ac-4a36-9d63-cca8dc6a29a6@www.fastmail.com>
Date: Thu, 11 Aug 2022 15:48:06 +0200
Message-ID: <CAOWwgpmee-vfAWsPkiSu826ST_vt8Nkp1Kp=ALH5WdXh6=7G0Q@mail.gmail.com>
To: Larry Garfield <larry@garfieldtech.com>
Cc: php internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="0000000000009ecc1005e5f774a1"
Subject: Re: [PHP-DEV] [RFC] Asymmetric visibility
From: nicolas.grekas+php@gmail.com (Nicolas Grekas)

--0000000000009ecc1005e5f774a1
Content-Type: text/plain; charset="UTF-8"

> Ilija Tovilo and I are happy to present the first new RFC for PHP 8.3:
> Asymmetric Visibility.
>
> https://wiki.php.net/rfc/asymmetric-visibility
>
> Details are in the RFC, but it's largely a copy of Swift's support for the
> same.
>

Thank you Larry and Ilija for this RFC.

After reading it, I'm wondering about inheritance rules. What would be the
rules when redeclaring an existing asymmetric property in a child class?
The RFC should mention them I believe.

But I'm also wondering about the use case where asymmetry would be useful
in practice now that we have readonly?
I voted against readonly at the time because it didn't address cloning, and
also because it deprives end-users vs code authors IMHO (alike "final"). I
would have very much prefered asymmetric visibility back then. But now that
we are here, what are the use cases? If it's cloning only, then I would
very much prefer finding a way to fix it rather than providing two subtly
different ways to achieve the same thing.

Eg can't we allow __clone methods to bypass the readonly restrictions? The
engine already handles "guards" when using magic property accessors. Can't
we use something similar for clone?

And if yes, what would remain of the motivations for the asymmetric RFC?

Cheers,
Nicolas

--0000000000009ecc1005e5f774a1--