bug#27162: [PATCH 0/6] Display how much will be downloaded

[Maxim Cournoyer]

Hi!

On Wed, May 31, 2017 at 6:49 AM, Ludovic Courtès <address@hidden> wrote:
> Hello!
>
> With this patch series, ‘show-what-to-build’ can display the download
> size and warn about lack of disk space when needed:
>
>   $ ./pre-inst-env guix build synfigstudio -n
>   substitute: updating list of substitutes from 
> 'https://bayfront.guixsd.org'... 100.0%
>   10.8 MB would be downloaded:
>      /gnu/store/jq80lq3xhib81fi2v6j7ygh7mqdjrjsx-synfigstudio-1.2.0
>      /gnu/store/azvp0257q9yhl0b409q1s6h67pfhaknr-libxml++-3.0.1
>      /gnu/store/bjmwcqxr32g48jzwc0zc993m8x3ymq5h-synfig-1.2.0
>      /gnu/store/lxmviq543w2a4ahc4c77i542sl921bbl-mlt-6.4.1
>   guix build: warning: at least 73.8 MB needed but only 42.0 MB available in 
> /gnu/store
>
> Thoughts?

This is really neat! Thanks for that. Shouldn't the default behavior
of build to stop right there (even without the -n flag) and errors out
when it "knows" there won't be enough space to successfully build the
derivations? This would prevent bad surprises and is still
non-interactive. If the current ability of failing a build because of
lack of disk space would still be desired for some reason, a force
flag could allow it anyway.

My 2 cents,

Maxim