[bug#44344] [PATCH] guix: describe: Improve package provenance tracking.

[Ludovic Courtès]

Hi Julien,

Julien Lepiller <julien@lepiller.eu> skribis:

> %load-path lists ~/.config/guix/current before individual channels.  We
> use canonicalize-path to get the store path for channel packages.
>
> * guix/describe.scm (package-provenance): Use canonicalize-path.

[...]

>       (let ((file (if (string-prefix? "/" file)
>                       file
> -                     (search-path %load-path file))))
> +                     (canonicalize-path (search-path %load-path file)))))

Could you explain what problem it solves, perhaps with a simple reproducer?

‘search-path’ can return #f (there’s a test right below), so this should
probably be: (and=> (search-path …) canonicalize-path).

As a rule of thumb, I think twice before calling ‘canonicalize-path’
because (1) it’s expensive (lots of stat(2) calls), and (2) it can have
undesirable effects on the UI (messages mention a file name other than
the one the user typed) and elsewhere (on logic that looks at what the
file name looks like).

Maybe it’s OK here, but I mention this for completeness.

Thanks,
Ludo’.