Adding detecting circular dependecies

[mamazu]

When a service has a dependency on another service in the same chain, this will silently fail and run out of memory. This adds an exception if a service has a dependency on itself.

[dantleech]

this would also impact performance for every call to get at runtime...

[mamazu]

Is there any other way of doing that? The alternative would be to add a build step like with the Symfony DI container.

[dantleech]

It could be done in a more efficient way probably, but with micro impact on performance (which isn't a problem with long running processes like Phpactor where it's just a small startup cost) but I'm still reluctant to change things on the hot-path or to add more complexity here.

Compiled containers introduce extra complexity with generally negative impact (can't use closures to build services, cache clearing etc, can't jump to instantiations as you can now etc).

[mamazu]

I'm open for suggestions. It definitely helps finding problems with accidental circular dependencies and not just a generic "out of memory" exception.

See phpactor/phpactor#2749