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

[Ludovic Courtès]

Hi,

Maxim Cournoyer <address@hidden> skribis:

> 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.

Good point!

On my previous laptop I was always short on disk space, so what I would
do is spawn ‘guix package’ or similar, and then once it had started, I
would start ‘guix gc’ in a separate terminal; that way I knew it’d only
GC things that don’t matter for the operation at hand.

Granted, that’s a bit far-fetched, but perhaps there are other
situations where you’d want to proceed anyway because you know you’ll be
freeing space somehow.

Now, maybe the default could still be to error out, and we’d have a
force flag as you wrote (--no-error-if-full?) for these other cases.
That would add a little bit of complexity though.

Ludo’.