Nullable types must be explicit

Thanks a lot for creating this issue and already providing a great merge request!

I don’t think we’ll have any problems with backwards compatibility here since making the nullability explicit makes no difference to PHP (except for the deprecation warning in PHP 8.4+). To test, just run the following locally (or run it on 3v4l.org):

class A {
  function foo(array $a = NULL) {}
}
class B extends A {
  function foo(?array $a = NULL) {}
}
class C extends B {
  function foo(array $a = NULL) {}
}

No warnings at all for PHP 8.3 and lower, just the expected deprecation warnings for 8.4.

No idea what went wrong with your pipeline there, but just re-running it worked fine. So, merged.
Thanks again!

Automatically closed - issue fixed for 2 weeks with no activity.

It would be very helpful to get a release with this change. Modules that depend on this module also display messages about this on PHP 8.4.

PHP does not see this as a change in the function signature, so a major version update is not needed.