PHP 8.4 Support

[Jubeki]

What is the reason for this PR?

• A new feature
• Fixed an issue

Author's checklist

• Follow the Contribution Guide
• New features and changes are documented

Summary of changes

• Adds PHP 8.4 to Test Matrix
• Add explicit nullable declarations to remove PHP 8.4 deprecations.
• Add nullable_type_declaration_for_default_null_value to Coding Standards

Review checklist

• All checks have passed
• Changes are added to the CHANGELOG.md
• Changes are approved by maintainer

[pimjansen]

Thanks! Will review later. Initially it all looks fine

[Jubeki]

I think the Static analysis / Psalm failure is unrelated to this PR.

[pimjansen]

I think the Static analysis / Psalm failure is unrelated to this PR.

Well im not even getting them locally indeed.

[pimjansen]

@localheinz you got an idea what this could be? Also the error makes no direct sense to me at all

[pimjansen]

Can we recreate the baseline here?

[Jubeki]

@pimjansen I have updated the baseline.

[Jubeki]

Seems like there is still a problem with the baseline.

I updated it using the following command:

vendor/bin/psalm --no-progress --update-baseline

(Never used psalm before)

[pimjansen]

Me neither so thats why i pinged @localheinz haha. Since i want this PR to be done so we can continue in other libs as well

[Jubeki]

@pimjansen Okay I have found the problem regarding the baseline.

The option --update-baseline will only removed solved problems from the baseline, it will not add new ones. For that you need to run --set-baseline=psalm.baseline.xml.

I have now added a regenrated psalm baseline, which should make this PR mergeable.

[pimjansen]

LGTM, cant somehow not merge this via mobile will review tomorrow and push for a 1.24 release

[pimjansen]

Good work!

[Jubeki]

Thanks!