On Mon, 14/10/2024 05:01, Jordan LeDoux <jordan.led...@gmail.com>: > > > > On Sun, Oct 13, 2024 at 5:03 PM Valentin Udaltsov > <udaltsov.valen...@gmail.com> wrote: >> >> On Mon, 14 Oct 2024 at 01:28, Jordan LeDoux <jordan.led...@gmail.com>: >> > Backwards compatible has never, in any work I've done through my entire >> > career, meant something like "if you take old code and then update it to >> > the new version incorrectly, it doesn't work"... that seems... obvious? >> > >> > What exactly is the claim being made here? Because it sounds like the >> > claim is very much that second "definition". >> > >> > Jordan >> >> Hi, Jordan! >> >> The problem is that in practice most of the PHP libraries consider >> themselves to be compatible with newer PHP versions. >> >> For instance, Symfony PropertyInfo uses `"php": ">=8.2"` constraint in >> its `composer.json`. However, it is not compatible with PHP 8.4, I've >> just created an issue: https://github.com/symfony/symfony/issues/58556 >> >> The end user will be the victim, because `composer require >> symfony/property-info` will happily install property-info v7.1.4 for >> PHP 8.4, but it's not gonna work. >> >> -- >> Valentin > > > How does a library that uses code that will not even compile (like `readonly` > or `private(set)`), but claims to not require a PHP version that uses the > syntax, suddenly make a BC problem for the language? Composer allows > libraries to set minimum PHP versions for releases. Any time you update your > libraries, you may have to update your code which uses it. That's just part > of how libraries work. > > Jordan
First of all, I have already agreed above that PHP does not have a BC break here. Now we are discussing the potential problems in the PHP ecosystem and how they could be mitigated. > Composer allows libraries to set minimum PHP versions for releases. I think you've got the problem wrong. The problem is about the maximum version, not the minimum one. Consider the Symfony issue I've just reported: https://github.com/symfony/symfony/issues/58556 Symfony PropertyInfo requires `php >= 8.2`. And it is written in PHP 8.2 syntax. So it can be safely installed and used in PHP 8.2 and 8.3. In other words it's forward compatible. However, the `php >= 8.2` constraint also allows installing it in PHP 8.4. And as it turned out, PropertyInfo is not ready for 8.4 syntax (see my reproducer https://github.com/vudaltsov/symfony-property-access-php84). In my opinion, this is a problem, because a PHP 8.4 user can install the library without any obstacles and only later find out that `private (set)` properties do not work as expected there. Ideally `symfony/property-info` should not be installable until it ensures to be compatible with all the PHP 8.4 features. So, its PHP constraint should be `>=8.2 && <8.4`. And then `>=8.2 && <8.5`, once the tests pass for PHP 8.4 features. -- Best regards, Valentin
