Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:117947
MIME-Version: 1.0
References: <CAPyj-LBQmoFEGZyMw3H5fAy-NwP3WdkH2ZviHWcBrhJ_8qrOGg@mail.gmail.com>
 <CAF+90c9t40aOg1N7FyL0nNVdWuqtuS60WbGQbqvBuApB_wdKQg@mail.gmail.com>
 <CAPyj-LBqmh865eOwvNC1v2=SQoJqz9xUPgp21eYnaKzt7i0F7Q@mail.gmail.com>
 <CAPzBOBO96J4-BfY9khNrDr7xM6OCmh8HSMBS8Ey1n9Ss-__9Kg@mail.gmail.com> <CAC5V6ghvv0uLq6nskZuNpOuM5eGS4MhMfYX+yHO6YvsR1QNH1g@mail.gmail.com>
In-Reply-To: <CAC5V6ghvv0uLq6nskZuNpOuM5eGS4MhMfYX+yHO6YvsR1QNH1g@mail.gmail.com>
Date: Tue, 14 Jun 2022 18:13:24 +0200
Message-ID: <CAPyj-LAF-Xf6Wwyi-RurfxYVQgmHhRKeFSTDbZo55hXgY1Ya7A@mail.gmail.com>
To: PHP internals <internals@lists.php.net>
Content-Type: text/plain; charset="UTF-8"
Subject: Re: [PHP-DEV] [RFC][Under discussion] Fetch properties in const expressions
From: tovilo.ilija@gmail.com (Ilija Tovilo)

Hi Robert, hi Guilliam

> > So, how does this change our mental models when writing PHP? For
> > example, I generally consider `const` to be a "compile-time" constant
> > (ie, generated/created before any code is actually executed). So would
> > this allow code to actually execute before any other code (ie, by
> > putting code in a __get()) and thus cause issues due to database
> > drivers and etc to not be loaded yet -- or cause them to be loaded
> > prematurely?
>
> True but that's already the case since PHP 8.1 and
> https://wiki.php.net/rfc/new_in_initializers
> (https://github.com/php/php-src/pull/7153), e.g.
> https://3v4l.org/MSWi0:
>
> ```
> class Foo {
>     public function __construct() {
>         echo "Side effect!\n";
>     }
> }
>
> const C = new Foo();
> ```

Exactly. In fact, the only way you could invoke arbitrary userland
code through __get is in combination with `new`, where side-effects
are already possible via constructor. Enums themselves don't allow
__get and thus can't lead to side-effects in constant expressions.

If there are no other concerns I'd like to open the voting phase by
the end of the week.

Ilija