Efraim Flashner <efr...@flashner.co.il> skribis:
> On Mon, Oct 17, 2016 at 10:50:36AM +0200, Ludovic Courtès wrote:
>> Ricardo Wurmus <rek...@elephly.net> skribis:
>> > 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?
>> “Failed” as in “there were no pattern matches”, right?
> Or as in "your regex was bad, try again"
That already happens.