Re: [PATCH] Documentation: kbuild: explain handling optional dependencies

[Arnd Bergmann]

On Fri, Sep 15, 2023, at 09:34, Jani Nikula wrote:
>
> IS_REACHABLE() considered harmful.

Absolutely agreed, and I'm sorry I introduced it in the
first place in commit 9b174527e7b75 ("[media] Add and use
IS_REACHABLE macro").

At the time, it was only used by drivers/media, which used
to have a lot of open-coded instances of it and a lot of
wrong checks.

Having a formal syntax for it was an improvement for
drivers/media since it was more broken before, but it's
usually a mistake to use it when there is another solution,
and we probably should have tried harder to fix the
dependencies in drivers/media at the time.

      Arnd