lib.optionals in place of lib.optional ?

[drupol]

Hello,

How about having a rule explaining why lib.optionals is a better idea than lib.optional ?

Here are some rough ideas:

1. Since lib.optional does more than expected. It wraps its contents into a list. This adds an extra cognitive load for newcomers.
2. Some people consider it harmful: https://discourse.nixos.org/t/lib-optional-considered-harmful/7081
3. Since we are dealing with buildInputs which is a list containing potential more than 1 element, using the plural form lib.optionals seems more natural.
4. Using lib.optionals allows you to add more than one element after the condition. If you try to do the same with lib.optional, you might end up with lists within lists.
5. I've been submitting a couple of PRs against nixpkgs before and some maintainers asked me to use lib.optionals instead of lib.optional.