Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:126610
Precedence: bulk
MIME-Version: 1.0
References: <aae32397-0567-417f-adbe-6b663d5c49ae@app.fastmail.com>
In-Reply-To: <aae32397-0567-417f-adbe-6b663d5c49ae@app.fastmail.com>
Date: Thu, 6 Mar 2025 23:20:37 +0100
Message-ID: <CAPyj-LAz=3yX7mCYOijw2irrubgs2b3Piqy42_jpkek5ctKkWA@mail.gmail.com>
Subject: Re: [PHP-DEV] RFC: short and inner classes
To: PHP internals <internals@lists.php.net>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
From: tovilo.ilija@gmail.com (Ilija Tovilo)

Hi Rob

On Thu, Mar 6, 2025 at 12:14=E2=80=AFAM Rob Landers <rob@bottled.codes> wro=
te:
>
> I'd like to introduce my RFC for discussion: https://wiki.php.net/rfc/sho=
rt-and-inner-classes

Thank you for your proposal.

I'm very much against the idea of introducing yet another slightly
shorter form to declare a class. In your examples (they have been
removed in the meantime), it's unclear how the syntax interacts with
inherited constructors, trait-used constructors, whether repetition of
readonly parent properties leads to a "Cannot modify readonly
property" error, etc.

The concept of visibility for classes does seem useful to me. Some
questions that crossed my mind when reading the proposal:

> Inner classes may only be nested one level deep, may not be a parent clas=
s, and may not be declared abstract

These restrictions seem somewhat arbitrary. For example, you may want
a private class to extend another private class, creating some local
class hierarchy. I think there's value in relaxing this restriction,
if technically possible.

> PHP Fatal error:  Private inner class Box::Point cannot be used in the gl=
obal scope

How is this implemented? I presume using a public nested class as type
hints should be allowed, but these classes may not be loaded when the
function is declared. We implement delayed variance checks for
methods, which do trigger the autoloader, but functions do not (since
they cannot violate variance rules).

> Visibility Rules: Private and protected inner classes are only instantiab=
le within their outer class (or subclasses for protected) and cannot be use=
d as type declarations outside their outer class. This encapsulation ensure=
s that the inner class=E2=80=99s implementation details remain within their=
 intended scope.

This introduces a weird case where methods with parameter or return
types referring to private classes may not be redeclared in their
subclasses, given that the type cannot be specified, even if the
methods themselves are not private or final. You do mention something
very similar in your e-mail with the __constructor case, but I really
fail to see how this provides any benefit.

I would also like to echo what has been said about the :: operator,
which feels out of place. I understand that \ comes with additional
autoloading challenges, namely requiring a fallback autoloading
strategy that currently does not conform to PSR-4.

Disclaimer: I have not looked at the implementation at all yet.

Ilija