Well, this is on purpose. The method is provided by symfony/polyfill-php80 which is required through symfony/console.
I (and probably others) think “oh, that would be a nice function to use” or stumble over “ah, is this available in all PHP versions we care support?”. Now, would those polyfill packages be a solution? It would:
make us think less
avoid errors due to unavailable functions
allow to “code for the future” already
The fact we have them already means we could require them explictly and then use them. In any case, adding replace statements as documented might be a good idea,
Though we probably need to add those to the Neos.Flow package itself as well
Regarding requiring the polyfills and making use of them - I’m a bit torn. Yes it allows to code for the future, but only within a select subspace - polyfills e.g. can’t provide union types, attributes or constructor property promotion. So one still has to think (or rather look) very carefully what to use and what not. Hence I think the benefit is rather shallow after all. I wouldn’t block adding them though
Good the changes are still in, btw… the merger would have thrown them out. If you ever change the collection manifest only with out touching another package file or the .composer.json template, you are missing something…