In this PR I also propose to highlight the .env files with shell instead of bash. The reason is that bash is wrapped with a fake console illustration, and that's wrong in this case.

Before

After

I don't understand this change. What's the solution? Just saying it does not work does not help our users. I would really prefer to fix this in Symfony instead. /cc @nicolas-grekas

There's been a misunderstandig then. Reading this note I thought you didn't want to add this feature to Dotenv:

PHP has a lot of different implementations of this "pattern". This
implementation's goal is to replicate what source .env would do. It
tries to be as similar as possible with the standard shell's behavior (so
no value validation for instance).

This talks about validation. Here, we are talking about container parameter replacement, which can work for both regular env vars and ones coming from a .env file.

This doesn't relate to Dotenv specifically to me: parameters are not resolved into environment vars, wherever it comes from. Or did I miss something?

Indeed, the question is "do we want to resolve parameters for all env vars"?

I'm closing this PR as this can be fixed thanks to symfony/symfony#23901