On Sat, Jul 14, 2018 at 10:00 AM Rowan Collins <rowan.coll...@gmail.com> wrote:
>
> On 14 July 2018 15:37:32 BST, Levi Morrison <le...@php.net> wrote:
> >> class Validity {
> >> public \DateTimeInterface $validFrom;
> >> public ?\DateTimeInterface $validTo = null;
> >> }
> >
> >Even if this had a constructor we couldn't "trust" it because there
> >are ways to skip constructors.
>
> Then the mechanisms should either be impossible with non-nullable properties,
> or have a way to mark the object initialised. If not, the object created
> would not be fully initialised, so accessing *the entire object* should be an
> error, not just accessing the specific properties which are marked
> non-nullable.
>
> I'm not claiming any of this is easy, but if you can't guarantee a property
> has a valid value, what is the type hint actually for?
Whether it's a constructor, a factory method, or just a block of code
near the `new` site: something has the responsibility for
initialization. Once initialized the object provides guarantees unless
you `unset` the property. It also provides the guarantee that if it is
set then it will always be of the outlined type; this is a much
stronger guarantee than we have today, which is... nothing.
It's worth discussing, and if someone has a brilliant idea maybe we
can proceed. However, in the absence of such an idea am I fine with
the outlined semantics of the RFC.
--
PHP Internals - PHP Runtime Development Mailing List
To unsubscribe, visit: http://www.php.net/unsub.php
