Re: Making substitute* throw an error if substition failed?

[Alex Kost]

Ricardo Wurmus (2016-10-15 00:05 +0200) wrote:

> Hi Guix,
>
> it happened a couple of times already that a “substitute*” expression
> silently failed and I only found out about it when investigating the
> remains of a failing build (“guix build -K”).  This can easily happen
> when a package is updated and substitutions “anchors” no longer exist in
> the updated source code.
>
> Would it be desirable to change “substitute*” (or replace it) such that
> it throws an error or returns a value if substitution failed?  This
> might be helpful for the more complex packages with many substitutions.
> If we make it return a value (#f for error) it would also make our build
> phases a little prettier, I think.  (Now we forcefully return #t in any
> case and that seems wrong.)

This was also discussed a bit around here:
<http://lists.gnu.org/archive/html/guix-devel/2016-09/msg01844.html>.
As I mentioned in that message, I'm for returning #t/#f for
succeeded/failed substitution.

-- 
Alex