Re: [PATCH] guix: build: Add transitive source building.

[ludo@gnu.org (Ludovic Courtès)]

Eric Bavier <ericbavier@gmail.com> skribis:

> This patch is intended mostly for discussion.  It was brought up again
> on IRC yesterday the idea of prefetching package source into the store
> in order to be able to hack on guix offline.

Excellent!

> +(define (package-source* package)
> +  "List package-source but returns its results as a list"
> +  (list (package-source package)))

What about using the plural, ‘package-sources’, which makes it clear
that it returns a list?

> +(define (package-direct-source package)
> +  "Return all source origins associated with PACKAGE; including origins in

Likewise, plural.

> +(define (package-transitive-source package)
> +  "Return PACKAGE's direct sources, and its input sources, recursively."

Ditto.

> I've tested this patch by building e.g. gmsh (which I did not already
> have in the store)::
>
>   $ guix build --source=transitive gmsh
>   [...]
>   <disconnect network>
>   $ guix build gmsh

Neat!  This is indeed the use case that had been discussed with Nikita a
while back.

> The build succeeded after building the glu, glproto, fltk, and
> xf86vidmodeproto inputs from source.  I haven't yet tried making a
> change that would require rebootstrapping while offline.  I think the
> idea is that this should work.

Yes.

> What I'd like to get some feedback on:
>
> 1. Adding an optional argument to `guix build --source` currently breaks
>    `guix build -S foo`, since the option parsing thinks "foo" is the
>    argument for -S.  I'm not sure how this could be reconciled.

I think this is a problem, perhaps because I’m used to ‘guix build -S
foo’ and I wouldn’t want to do more typing for something like this.  ;-)

I can think of two options to work around it:

  1. Add a separate option, say, --sources={transitive,all,package}.

  2. Make it a separate command, say ‘guix prefetch’ with just the
     option ‘--sources={transitive,all}’.

WDYT?

> 2. There might be clearer user/developer-facing names for the arguments.

I think that’s fine.

> 3. Am I understanding the use-case?

I think so.  Andreas notes that when one just plans to modify a leaf
package while on the train, running something like ‘guix environment
the-leaf -E true’ is enough to fetch the dependencies of that package.
But I think that’s a slightly different use case anyway.

Thanks,
Ludo’.