[bug#52486] [PATCH] gnu: deluge: Move librsvg to native inputs.

[Leo Famulari]

On Tue, Dec 14, 2021 at 06:21:51PM +0100, Josselin Poiret via Guix-patches via 
wrote:
> Grepping the source code shows that librsvg is run by the
> builder, and not by deluge itself.  This fixes propagation conflicting
> with gtk+'s librsvg.  For now, use the C variant to build on all archs.
> -- >8 --

I applied your patch and built Deluge. Then, I checked what packages it
keeps a reference to:

------
$ guix gc --references $(./pre-inst-env guix build deluge) | grep librsvg
/gnu/store/2dza2psfbrrbvsni8jjqzzqx3hmm8kw8-librsvg-2.50.7
/gnu/store/zxpbc78z40x7dr3ls4dgclkq7i4agx7a-librsvg-2.40.21
------

So, Guix already records a run-time dependency on the Rust variant of
librsvg (likely via GTK+), as well as the C variant if we apply your
patch.

I agree that, if Deluge does not use librsvg at run-time, we should make
it a non-propagated-input. But, we should use the Rust variant on
platforms where it is supported. Check the package definition of GTK+
for an example.

And we should also make it a 'regular' input, because the package does
keep a run-time reference to it.

We are phasing out the C variant because it is abandoned upstream and no
longer receiving security updates.