On Thu, Jul 2, 2015 at 3:34 PM, Philip Hofstetter < phofstet...@sensational.ch> wrote:
> Hi, > > as this probably requires some discussion, I'm coming here to ask. > > I'm talking about bug 69977 and 61483: Both are about the fact that it's > currently not possible to properly type-hint descendant classes of DateTime > and friends. > > The reason is the missing use ZEND_ARG_OBJ_INFO, so right now, users can > only create descendant classes without any type hinting on their methods. > > Adding the ZEND_ARG_OBJ_INFO is quite trivial and in-fact, I have a branch > here that does it: > > https://github.com/pilif/php-src/tree/bug-69977 > > Of course this is going to break a whole lot of tests because what was once > warnings is now a TypeError. > > I'd be willing to update all the tests as needed, but of course changing > the behaviour like this is a BC issue in itself, hence I'm coming here. > > The reason why I think this matters much more now than back when 61483 was > submitted is two-fold: > > 1) back in 61483, adding the (correct!) type-hints was "just" causing an > E_STRICT message. But now with PHP7 it's actually an E_WARNING. So people > running without E_STRICT enjoyed correct type hints until now which they > now can't any more (so, there's another BC break right there :p) > 2) With PHP7 type hinting becomes much more viable, so forcing users to not > type-hint something that really should be feels kind of ugly. > 3) Having a new major release is as good a time as any for chaning the > behaviour, especially when the change is related to a major new feature > (the addition of much stricter typing). > > So I'm asking for opinions on what should be done here. > > Again: If you lean /at all/ in the direction of changing this, I volunteer > to update all the tests as required. > > Philip > This change is currently not possible, because it will cause a significant BC break for everyone extending DateTime: They would now be required to specify these typehints as well. However some libraries (including Carbon, which is used a lot) depend on these typehint not being there, because they overload them to e.g. allow passing a string which will then be converted to the correct instance before passing off to DateTime. A similar change to what you propose was reverted from PHP 7 for this reason. However, what we can do in PHP 7.1 (and I plan to write an RFC for this) is allow extending classes to remove a parameter type hint, which is in accordance with contravariance of parameter types. This is analogous to our already existing partial covariance support for return types (which works the other way around, by allowing to add return typehints in extending classes). Nikita
