Add test case to show shortcomings of nesting & factory

[SamMousa]

This shows that nesting doesn't work as expected since we're losing scope as soon as we pass the request on to the parent.

[SamMousa]

https://github.com/container-interop/fig-standards/blob/master/proposed/container-meta.md#7-delegate-lookup-feature

At the very least we should clearly and explicitly document what choices we have made regarding delegated lookups.

[SamMousa]

PHP-DI solves it by passing the parent into the child as well, that way the child can resolve dependencies via the parent: https://github.com/PHP-DI/PHP-DI/blob/master/src/Container.php#L96

Some more reading: https://thecodingmachine.io/psr-11-an-in-depth-view-at-the-delegate-lookup-feature

[samdark]

We choose to support delegate lookups with fallback strategy: if there's no service registered in a container it is being checked in its parent.

[SamMousa]

Yeah, but fallback should resolve child dependencies in the root container.

We could create a simple composite container for this purpose. I'll do some more research

[samdark]

Yeah, but fallback should resolve child dependencies in the root container.

Correct.

[SamMousa]

That problem (I think) is hard to solve with parent container approach (which creates trees). Instead we should implement a composite container 😵 I'll think on this and make a PR next week.

[samdark]

Alternatively we can remove support for container nesting altogether. I was thinking about using it for modules initially but still not sure about it.

[SamMousa]

Even better. We can always implement it if we need it in the future.

[SamMousa]

On the other hand, if we have a composite container that could be a simple way to implement overrides *-)

[samdark]

Well, check it if you want to but don't spend too much time on it. We don't depend on this feature much and can live w/o it.

[hiqsol]

Parenting is already used to have factory container as a child of main container.
But afaics it is not really used in core or elsewhere.

[samdark]

There's no need for it. Scrutinizer has PSR2 rules built-in.

[samdark]

Seems to be no longer valid.