Re: (propagated) 'inputs' depends on 'outputs'?

[Ricardo Wurmus]

zimoun <zimon.toutoune@gmail.com> writes:

> On Sat, 13 Jun 2020 at 12:16, Christopher Baines <mail@cbaines.net> wrote:
>
>> Looking at different outputs, the references are different. If you're
>> just using the "out" output, then you don't need subversion in your
>> store, but if you're using the "svn" output, then you do, as that output
>> references an output for subversion.
>>
>> The references for an output isn't something specified, but something
>> decided by what references that output actually contains.
>
> I understand.
>
> Back to the Git's example, there is still something I miss: I cannot
> build Git from source (e.g. no substitutes) using "guix build git"
> without downloading -- and possibly building too -- all the Subversion
> stuff.

That’s correct.  Outputs are buckets into which we drop build
artifacts.  We will build everything with all inputs in one derivation
and then move stuff into output buckets.  This means that you can
download independent outputs individually, but they are still all the
result of that *single* derivation.  So to build any of the outputs you
will need to build that derivation, even if it also results in other
outputs that you don’t care about.

-- 
Ricardo