[Config] [Configuration] Add $_ENV and $_SERVER example with .env

[alexandre-daubois]

Fixes #17693

[xabbuh]

Is it really a common use case to access environment variables through the superglobal arrays? I usually reference them inside my service configuration with %env(...)% instead (values are injected into services this way instead of having code depend on global state).

[alexandre-daubois]

I wouldn't say it is "common" but this is something that can happen, especially when using the Dotenv component as a standalone. But I may add a note to inform that best practices is to inject env vars through %env()% maybe?

[xabbuh]

I think I would put it the other way around: Show examples how to make use of the env processor in the DI config and add a short sentence explaining that you could also access the value through the superglobal arrays.

[alexandre-daubois]

I moved the paragraph below the examples with %env()% and reworded a bit to indicates that env vars may be accessed in the code. Is it better? 🙂

[javiereguiluz]

Thanks Alex!

Similar to Christian, I was a bit concerned about this. So, while merging I "demoted" this explanation to a note and added a message to warn readers that they should really not use this in Symfony apps. See 3a4b017