Make `ReflectionConstant` non-final

[kukulich]

Description

It's the same problem as #7520 and it's beautifully explained here: https://bugs.php.net/bug.php?id=81474

I must admit that we missed that ReflectionConstant was created in PHP 8.4.

The following code:

<?php

$rc = new ReflectionClass(ReflectionConstant::class);

var_dump($rc->isFinal());

Resulted in this output:

bool(true)

But I expected this output instead:

bool(false)

PHP Version

PHP 8.4

Operating System

No response

[TimWolla]

This is not a bug and cannot be changed for PHP 8.4 at this point. For master, this would require RM approval (incidentally one of the RMs, @DanielEScherzer, is the reflection maintainer).

[mvorisek]

To prevent this in the future test like https://3v4l.org/J1q6t would be good.

This is a slight design bug and IMO this can be changed even for PHP 8.4, the repro shows it was actually changed for PHP 8.0 (for ReflectionAttribute class) as well.

[TimWolla]

A missing feature is not a bug. At this point, PHP 8.4 is already packaged and released in long-term support distros (most notably Debian Trixie). This change will not reliably make it to the users and no one expects the public API to change within a released PHP branch.

[kukulich]

@TimWolla Please see previous issue. It was even backported to 8.0 (e286313) because it's not a BC break.

[TimWolla]

because it's not a BC break.

By that argument, we could backport every feature for any PHP version to any other PHP version when they do not result in a BC break. Making something possible that previously was not possible is not a bugfix, but a feature.

[krakjoe]

That it was not a BC break is incidental ...

We made an exception for a popular community component, which at this time has nearly 11 million downloads.

In my opinion, we also implicitly committed to maintain that external components ability to function (and be developed alongside php), and we obviously have violated that implied agreement.

There is as much justification for back porting this as there was in the first instance, if not more because of it's extended user base all these years later.

[iluuu1994]

As the author of ReflectionConstant, I don't mind making this class non-final. However, the original argument doesn't apply in this case, as no other reflection class returns ReflectionConstant instances. BetterReflection could simply proxy the relevant methods until the class becomes non-final, iiuc. So maybe let's re-open GH-19901 and target master instead.

[kukulich]

BetterReflection could simply proxy the relevant methods until the class becomes non-final

The BetterReflection adapter needs to extend the class.