Update return types for hash functions

[jlherren]

This consolidates HashHmacFunctionsReturnTypeExtension into HashFunctionsReturnTypeExtension (the two classes were very similar) and adds support for hash_file(), hash_hkdf() and hash_pbkdf2().

It now also deduces the return type correctly when writing hash($cond ? 'md5' : 'sha256', ...).

I also added non-empty-string for return types and parameters. Return types should be fine, but I'm not sure whether it's too dangerous to narrow function parameters from string to non-empty-string, since that's likely to cause new errors. If that's not desired, I can remove them again.

Finally, I'm not sure about why there was logic to treat a mixed argument for the $algo parameter in such a way, that these functions would return (string|false), but I left it like that. Perhaps this can be changed to string|false?

[ondrejmirtes]

Hi, the build failed, also please fix the conflict :) Thank you.

[ondrejmirtes]

BTW there are some build failures on current master (in testing 3rd party projects coming from phpstan/phpstan) so beware, I hope to fix them soon.

[jlherren]

Thank you! Yes, I currently struggle in writing test that are expected to behave differently between PHP 7.4 and PHP 8.0+. Specifically, some of those functions no longer return false in PHP 8. But I'm not yet sure how to test that with NodeScopeResolverTest. I'll continue trying when I get time again.

[ondrejmirtes]

You can yield different files based on PHP_VERSION_ID :) It's already happening in that test a few times :)

[jlherren]

I think I got it sorted out now (not yet pushed). However, I came across this bug that affects the PHP 8 stubs. I'll wait to see what happens over there and update the stubs once that is fixed.

[jlherren]

Okay, the stubs are fixed, let's try again :) This time I also removed non-empty-string from parameters, it seems it causes too much troubles.

[ondrejmirtes]

This might be fine, the failures are unrelated, I'm gonna review it soon :) Thank you!

[ondrejmirtes]

Thank you! Merged: 1ec1c91