A reflection parser is not required here, and we already know how to get the type of arguments that use non-existing classes:
https://github.com/symfony/symfony/blob/master/src/Symfony/Component/VarDumper/Caster/ReflectionCaster.php#L218-L234

@nicolas-grekas Really? This PR solves the problem with existing classes that depend on non-existing classes. That's a big difference.

Do we really need to get information about such classes?

Yes, see #18188

👎, using a static parser will be a disaster from a perf point of view for an edge case (when it is called).
I prefer an error here than using such heavy logic. But there is maybe another way to fix the bug (using an error handler or something like that).

@dunglas The static parser is an optional as same as ocramius/proxy-manager for lazy services. Would you rather let the Symfony throwing fatal errors?

Ok I missed that it was in require-dev...

I've some concerns anyway:

1. are you sure that there is no lightweight solution (an error handler for instance)?
2. is it really justified to add (and maintain) this code for an edge case like this one?

I don't know how to catch fatal errors in PHP < 7, register_shutdown_function is not a solution.

So, I played a bit with this corner case, looks like there is no other way around, even in PHP 7 where missing parent classes are hard fatal errors, not \Error.
See https://3v4l.org/v0T0n

Ok +0 as there is no other solution.

Shouldn't this be applied on 2.8 (I did not check)?

@hason see patch proposal here: master...nicolas-grekas:no-parent
But the class loader of GoAOP is not compatible with Symfony's DebugClassLoader, which means this is currently useless in the dev env, where it should be most valuable.

@dunglas @nicolas-grekas What do you mean about a method that toggle static reflection?

Given this covers really an edge case, I'd personally prefer not adding any new public interface for it. That's why and how I proposed the previous suggestion.

Hello, guys! I noticed that you faced this ugly issue with unavailable parent classes. It's really bad one and sadly can be solved only with static reflection.
In personal, I don't like adding this static reflection library for symfony as dependency, because it's slow and will require a lot of time to process the code for big instances, however, cache warming process can solve this issue.

@nicolas-grekas @lisachenko This feature is optional and has to by enabled by Symfony\Component\DependencyInjection\Util\ReflectionHelper::preferStaticReflection(true);.

Looks like we are allowed to throw in the autoloader, thus work around this fatal error with a throwing autoloader. See #18600

Closed in favour of #18600.