Request #75765 Throw exception instead of a fatal error when extends/implements

[timurib]

Extending an undefined class or implementing an undefined interface causes the fatal error instead of throwing Error exception. Relevant issue: https://bugs.php.net/bug.php?id=75765
This patch is attempt to fix it.

I'm not fully understand the status of current behavior: it is intentional or not. Most of fatal errors was replaced by exceptions, but some errors are still handling in "old manner". As said in the docs, a bugfix PR should be branched against the lowest actively supported branch. But I not sure about BC things, if someone depends on current error handling of this cases. Also the patch cannot be applied for previous versions "as is", because it affects some lines which was changed between versions. So far I've created a branch against master.

[timurib]

As nikic said, supporting this would require larger changes. I closed the PR, sorry.

[nikic]

If you like, we can land the extends part of this PR, because this is safe. The parent class is fetched prior to binding, so there is no issue there. We only run into problems with multi-phase binding for interface implementations and trait uses.

[timurib]

You are right, the implements is trickier:

try {
	class A implements B {}
} catch (Throwable $e) {
	var_dump(class_exists(A::class)); // Ouch! 
}

With extends this does not happen, but I decided that I missed some other case. Thanks for the explanation.

I will remove all about the interfaces and improve the tests and re-open the PR.

[timurib]

Looks like github prohibits to reopen a PR after force-push (I'm rebase & squash the branch).
Should I open a new PR?

[nikic]

Yeah, please do so.