[HttpKernel] Move @internal from AbstractSessionListener class to its methods and properties

[Florian-Merle]

Q	A
Branch?	5.4
Bug fix?	yes
New feature?	no
Deprecations?	no
Issues
License	MIT

The AbstractSessionListener being marked as internal, its public constant NO_AUTO_CACHE_CONTROL_HEADER should not be used while the documentation states it can.

In fact, static analysis tools like psalm says there is an error with code using this constant.

ERROR: InternalClass - xxx.php:32:33 - Symfony\Component\HttpKernel\EventListener\AbstractSessionListener is internal to Symfony but called from xxx (see https://psalm.dev/174)
        $response->headers->set(AbstractSessionListener::NO_AUTO_CACHE_CONTROL_HEADER, 'true');

Another solution is to make every method of the AbstractSessionListener internal but this means the class could be extended.
Also, maybe the class AbstractSessionListener should not be internal, but I don't think so.
This is why I introduced a new interface that is not internal and allows to not introduce BC.

The documentation will need to be updated if this pull request is merged, I'd be happy to do it later.

As discussed, I made public/protected properties and methods internal and removed the original internal mark on the class.
This solves the issue and allows us to use the AbstractSessionListener::NO_AUTO_CACHE_CONTROL_HEADER const just like the documentation says we can.

[carsonbot]

Hey!

I see that this is your first PR. That is great! Welcome!

Symfony has a contribution guide which I suggest you to read.

In short:

• Always add tests
• Keep backward compatibility (see https://symfony.com/bc).
• Bug fixes must be submitted against the lowest maintained branch where they apply (see https://symfony.com/releases)
• Features and deprecations must be submitted against the 7.1 branch.

Review the GitHub status checks of your pull request and try to solve the reported issues. If some tests are failing, try to see if they are failing because of this change.

When two Symfony core team members approve this change, it will be merged and you will become an official Symfony contributor!
If this PR is merged in a lower version branch, it will be merged up to all maintained branches within a few days.

I am going to sit back now and wait for the reviews.

Cheers!

Carsonbot

[chalasr]

I suggest to make AbstractSessionListener @final instead of @internal remove the @internal flag from the abstract class and mark all of its methods as @internal instead, so we don't have to introduce an interface for a single constant and this PR can target 5.4 as a bugfix.

[stof]

an abstract class being defined as @final does not make any sense.

[chalasr]

Right, stoffed again 😅
Proposal updated to just mark its methods as internal.

[chalasr]

Should be reverted as changelogs are auto-generated for bugfix releases

[chalasr]

with minor comment

[fabpot]

Thank you @Florian-Merle.