bug#55583: guix-daemon doesn't cleanly error-out on case-insensitive file systems.

[Brian Cully via Bug reports for GNU Guix <bug-guix@gnu.org>]

Maxime Devos <maximedevos@telenet.be> writes:
> Not sure how a case-insensitivity would cause this, but I think 
> we
> can keep this open -- wouldn't it be better if "guix-daemon" 
> just says
> ‘nope, case-sensitivity is required (*), not continuing)?
>
> (*) For reproducible builds, and apparently for substitution.

The issue is wide-spread: there are a number of packages that will 
install files who’s names only vary by case. It’s also 
per-package; most work fine, but some will just break 
randomly. Some don’t seem to break until you try to use them, and 
then they yell and complain. This is something I run into often 
enough that it’s familiar to me and know how to fix, but not often 
enough to prevent my surprise when it happens.

Guix can’t fix it, unfortunately. Maybe checking case sensitivity 
would be a worthwhile thing to do, just to warn people, but: I 
don’t know of a good way to check this in a file-system 
independent manner, and I honestly doubt it’s something that 
actually happens that often. I’ve been trucking a ZFS storage pool 
around since I first installed it on macOS about a decade ago, and 
since macOS is case-insensitive, that’s how it was installed (case 
sensitivity causes its own issues there). Short of running Guix on 
Windows or macOS, I don’t see this being a problem.

-bjc