Treat constructors as implicitly void-typed for the purposes of prependCodeToFunctions()

[antecedent]

See #213.

The title assumes use function Patchwork\CodeManipulation\Actions\Generic\prependCodeToFunctions.

[jrfnl]

@antecedent I've been running the BrainMonkey tests with this branch to see whether it would fix the test failures BrainMonkey was seeing on PHP 8.6.

As things were, half the test failures were fixed. Looking at what remained showed me the oversight, namely that the same PHP RFC also forbids returning from a __destruct() method.

I've tried to fix that with the additional two commits (sorry, didn't mean to push to this branch, but as I did, the commits are here now), but while the fix works *, the test I added does not.

* The reason I'm saying the fix works is that the BrainMonkey tests pass on PHP 8.6 with the additional fix in place.

Hope this helps.

[antecedent]

Thank you @jrfnl! It looks like the missing link was NamedObject having no __destruct() defined in the first place.

I found it striking that Patchwork did not throw anything from the redefine('NamedObject::__destruct', ...), and I think you will find it that way too. The class already exists, and the method does not, so it would make sense to assume that it never will, and to throw a relevant exception. I think we should change that in the next minor release. What do you think?

[jrfnl]

Thank you @jrfnl! It looks like the missing link was NamedObject having no __destruct() defined in the first place.

Yes, that would explain it. Sorry I missed that.

Should we also add some tests with an anonymous class with a __construct() and __destruct() method to safeguard that the fix works correctly for such code too ?

I found it striking that Patchwork did not throw anything from the redefine('NamedObject::__destruct', ...), and I think you will find it that way too. The class already exists, and the method does not, so it would make sense to assume that it never will, and to throw a relevant exception. I think we should change that in the next minor release. What do you think?

If you mean that Patchwork should throw an exception when redefine() is called with a function/method name which doesn't exist on the original, then yes, I think that would be helpful for users (though outside the scope of this PR as this is fixing a specific PHP 8.6 issue).