Throw when passing an empty array to mget() instead or returning false

[alexandre-daubois]

Fix #1810, related to symfony/symfony#52700 and symfony/symfony#52668

The stub doesn't allow false to be returned, however that's what happen when calling mget with an empty array. I propose to throw an exception about it when this happen. This allow to keep the current mget return type.

[dkarlovi]

#1810 implied they don't want to throw exceptions, probably the signature needs to change. They said this would require a major release which in the meantime happened (v6) so from my POV the signature not being updated in the v6 is a bug, it shouldn't be seen as a BC break, it was just forgotten before v6.0.0 release.

[alexandre-daubois]

This is not what I understood from the issue 🤔 that an exception is a better solution than returning false. If you're going to introduce a breaking change, we might as well implement the exception?

[dkarlovi]

#1810 (comment) is arguing returning false is better since it's not possible to return false as a non-error condition.

In that case, since the current behaviour is the intended behaviour, I'd argue the stub needs to be updated to reflect that and it not being updated for v6 is a bug. Maybe @yatsukhnenko or some other maintainer can weigh in.

/cc @greg0ire