Subject: bug#22933: M-x guix-edit fails gracelessly when passed an nonexistent package name

From: Alex Kost <[email-masked]>
Date: Tue, 08 Mar 2016 02:01:29 +0300

Ludovic Courtès (2016-03-07 19:28 +0300) wrote:

> Currently M-x guix-edit fails badly (actually ‘guix-package-location’)
> pwhen passed the name of a nonexistent package:
[...]
> I think this patch fixes it:
>
>
> diff --git a/emacs/guix-main.scm b/emacs/guix-main.scm
> index 34da6ac..c5d5d75 100644
> --- a/emacs/guix-main.scm
> +++ b/emacs/guix-main.scm
> @@ -954,10 +954,14 @@ GENERATIONS is a list of generation numbers."
>  
>  (define (package-location-string id-or-name)
>    "Return a location string of a package with ID-OR-NAME."
> -  (and-let* ((package  (or (package-by-id id-or-name)
> -                           (first (packages-by-name id-or-name))))
> -             (location (package-location package)))
> -    (location->string location)))
> +  (define package
> +    (or (package-by-id id-or-name)
> +        (match (packages-by-name id-or-name)
> +          (() #f)
> +          ((first . rest) first))))
> +
> +  (and package
> +       (location->string (package-location package))))
>  
>  (define (package-source-derivation->store-path derivation)
>    "Return a store path of the package source DERIVATION."
>
> Thoughts?

Great!  Thanks for fixing it!  Feel free (you or Mathieu) to push any of
your patches.

-- 
Alex