Re: better error messages through assertions

[Ludovic Courtès]

Ricardo Wurmus <rekado@elephly.net> skribis:

> Maxim Cournoyer <maxim.cournoyer@gmail.com> writes:
>
>> I hear we now have "field sanitizers" on Guix records; without having
>> dug the details, it seems to be we could add a predicate validating the
>> input there?
>
> I don’t see how that would help here.  In my example the service values
> themselves are all right.  It’s a procedure acting on what it assumes is
> a list of service values that fails.
>
> Record field validation would not have prevented that error.

I think we could validate primarily at the user/core boundary.  If the
‘services’ field had a sanitizer ensuring it’s a list of services, then
it’d be fine.

Ludo’.