[DependencyInjection] Deprecate ContainerInterface aliases

[nicolas-grekas]

Q	A
Feature PR	symfony/symfony#35879
PR author(s)	@fancyweb
Merged in	5.1-dev

[javiereguiluz]

I've browsed the docs and I found 3 occurrences of the deprecated aliases:

1. This example in the main DI article: https://github.com/symfony/symfony-docs/blob/master/service_container.rst#public-versus-private-services

2. This example in the "service subscribers and locators" article: https://github.com/symfony/symfony-docs/blob/master/service_container/service_subscribers_locators.rst#defining-a-service-subscriber

3. This example in "service decoration": https://github.com/symfony/symfony-docs/blob/master/service_container/service_decoration.rst#control-the-behavior-when-the-decorated-service-does-not-exist

I guess we don't need to do anything for 3) ... but I'm not sure what to do with 1) and 2), so we'll need help. Thanks!

[nicolas-grekas]

3) is fine yes, unrelated. 2) is not using the main container but a dedicated locator (that's the whole point of service subscribers), nothing to do either.
1) needs to be rewritten yes, a sentence like "This is mostly useful when you want to fetch services lazily:" is misleading nowadays, service subscribers provide the same benefit without the drawback.

[fancyweb]

IMO, on number one :

which can also be injected thanks to autowiring

We just need to remove this part. It is still true but it not automatic anymore. If we keep it, we need to highlight the fact that this is not done automatically anymore.

Number 2 and 3 and not concerned.

[etshy]

Sorry for necroing this issue but I'm upgrading a fiw projects fro 5.4 to 6.4 and I have a different opinion about 2.

I know we don't have the full container in a locator, but why not recommending using ServiceProviderInterface, the direct interface of ServiceLocator, which extends ContainerInterface ?

It would be less confusing about the deprecation of ContainerInterface usage but stil seeing it on some part of the doc, even if unrelated.

[javiereguiluz]

@etshy please, create a new issue in this repository mentioning this so we can discuss about it. Otherwise, your comment will be lost because we don't track comments on closed/merged issues/PRs. Thanks!