From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ludovic =?UTF-8?Q?Court=C3=A8s?= <ludo@gnu.org>
Subject: bug#36592: no output for guix package -f when the file evaluates to
 nothing
Date: Fri, 20 Sep 2019 09:42:22 +0200
Message-ID: <87mueztnvl.fsf@gnu.org>
References: <D62FD64C-F99A-4D36-8DCB-9D2DED3F3A74@lepiller.eu>
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In-Reply-To: <D62FD64C-F99A-4D36-8DCB-9D2DED3F3A74@lepiller.eu> (Julien
 Lepiller's message of "Thu, 11 Jul 2019 11:31:04 +0200")
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To: Julien Lepiller <julien@lepiller.eu>
Cc: 36592-done@debbugs.gnu.org

Hello,

Julien Lepiller <julien@lepiller.eu> skribis:

> Users tend to copy what they see in our code base, so it's not rare to ha=
ve to help them realise that if their last statement is (define-public ...)=
, the file doesn't evaluate to a package.
>
> Running guix build -f mypackage.scm at least gives an error saying it doe=
sn't know how to compile #<unspecified>.
>
> Running guix package -f mypackage.scm returns immediately with no error m=
essage and a status of 0, but doesn't actually build or install anything. Y=
ou can even try with an empty file :)
>
> There should be an error message, and probably even a hint.

Fixed in f9c0400392843540a87985a67ffb9fb6e4dbc2fa.  It doesn=E2=80=99t prov=
ide a
hint though.

I thought we may want to provide =E2=80=98load*=E2=80=99 a type predicate t=
hat it would
check, so that it can say =E2=80=9Cgot #<undefined>, expected <package>=E2=
=80=9D.
However, we=E2=80=99d need a contract rather than a mere predicate to have =
nice
error reporting, so I decided to punt on this for now.

Ludo=E2=80=99.