Deprecate dynamic property creation with #[AllowDynamicProperties] escape hatch

[nikic]

This is a variant of #7390 that adds an #[AllowDynamicProperties] escape hatch, to explicitly allow using dynamic properties on a class without deprecation.

RFC: https://wiki.php.net/rfc/deprecate_dynamic_properties

TODO: Plaster #[AllowDynamicProperties] over large swathes of tests.

[TysonAndre]

I had some minor comments/questions, easily fixable

[othercorey]

While leaving the merits of this change to the voters, we had a technical question about this implementation.

Our framework uses dynamic properties to load models in a base class which all user app extend for each MVC + route connection. This is sometimes done with a trait in the child class and sometimes automatically in the base class.

Will this evaluate the AllowDynamicProperties permission from the child class only or will adding the attribute to the base class allow both child and base class to create dynamic properties?

[nikic]

While leaving the merits of this change to the voters, we had a technical question about this implementation.

Our framework uses dynamic properties to load models in a base class which all user app extend for each MVC + route connection. This is sometimes done with a trait in the child class and sometimes automatically in the base class.

Will this evaluate the AllowDynamicProperties permission from the child class only or will adding the attribute to the base class allow both child and base class to create dynamic properties?

The attribute also affects child classes. Quoting from the RFC:

Classes marked with #[AllowDynamicProperties] as well as their children can continue using dynamic properties without deprecation or removal.

If you add the attribute to the base class, then all classes that inherit from it can use dynamic properties as well. (You do need to extend from it -- using a trait with the attribute or implementing an interface with the attribute won't have an effect. And now that I say that, the implementation should probably explicitly forbid doing that.)

[uberbrady]

(Comment deleted and replaced with message to php internals list: https://news-web.php.net/php.internals/116519 )

[nikic]

Merged as 902d643.