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Date: Fri, 3 Jun 2022 16:35:21 +0200
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To: Robert Landers <landers.robert@gmail.com>
Cc: 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: guilliam.xavier@gmail.com (Guilliam Xavier)

On Fri, Jun 3, 2022 at 3:26 PM Robert Landers <landers.robert@gmail.com> wrote:
>
> 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();
```

but as https://externals.io/message/113347#113607 says,
"side-effecting constructors are a terrible idea", and same can be
said for "side-effecting [magic] getters"...

Also note that this only concerns *global* (or namespace-scoped)
constants (which can also be defined "dynamically" with `define()`),
not *class* constants.

-- 
Guilliam Xavier