On Wed, Nov 10, 2021 at 10:13 PM Jeremy Mikola <jmik...@gmail.com> wrote:
> > > On Tue, Nov 9, 2021 at 4:30 AM Nikita Popov <nikita....@gmail.com> wrote: > >> >> In >> https://github.com/php/php-src/commit/a551b083073ea08f8fc53b0e1a6380b6de26cc6b >> I've added a hack to add the string return type if it is missing and thus >> make the signature compatible with the interface. That should address the >> immediate compatibility issue. >> > > Thanks for the quick fix. > > A related question that came up, and is most likely unique to ext-mongodb, > follows. Many of our classes with toString() methods also implement a > corresponding interface with a toString() method. For example: > > * https://www.php.net/manual/en/class.mongodb-bson-binary.php > * https://www.php.net/manual/en/class.mongodb-bson-binaryinterface.php > > I'm in the process of adding explicit return type info to _all_ of our > toString() arginfos (classes and interfaces), but a thought occurred to me > that doing so may be a subtle BC break for userland classes implementing > these interfaces, since an explicit string return type would then become > necessary. But if I only modify our classes and leave our interfaces as-is, > PHP rightfully reports an error because the class' toString() method cannot > conform to both Stringable (with type info) and our interface (without type > info) -- at least PHP versions before 8.1.0RC6. > > Reading the patch above, it looks like the automatic Stringable > implementation only kicks in when the arginfo has no existing return type > info. In that case, I think the only option to completely avoid a BC break > would be to continue to leave our return type info omitted (on both our > classes _and_ interfaces) and allow PHP 8.1+ to apply it automatically. Is > that correct? > With the introduction of Stringable PHP also started automatically adding the string result type to __toString(), specifically for compatibility with the interface. As such, it should be safe to add the string return type everywhere for PHP >= 8.0. (If you use stubs with legacy arginfo, that would automatically give you the right behavior: types on PHP 8, no types on old versions.) Regards, Nikita
