bug#46246: VTK fails to build, breaking FreeCAD and others

[zimoun]

Hi Leo,

On Mon, 01 Feb 2021 at 17:31, Leo Famulari <leo@famulari.name> wrote:
> As previously discussed during the recent staging cycle, VTK is failing
> to build, which in turn prevents FreeCAD from building:

[...]

> Here's what I wrote during the staging cycle:
>
> ------
> For example, the vtk package is broken due to incompatibility with new
> Freetype, which breaks FreeCAD. On #guix, Marius said "I looked into VTK
> before the holidays; the Freetype issue is fixed in version 9, but that
> has other problems, such as making it impossible to unbundle the dozens
> of libraries that we are currently unbundling [...] it is possible to
> backport the VTK commits that fix Freetype compatibility, but it will be
> a lot of work and a huge patch (it was a major cleanup IIRC)." I'm
> CC-ing Ekaitz Zarraga, who has been working on FreeCAD. I'm not sure
> what we can do about this problem in the short term. Marius, can you
> give more info about the bundling problem?
> ------
>
> Ultimately, it seems to be a compatibility issue, combined with
> difficulty of "updating our way out of it". Maybe we should re-instate
> the graft? I know it's icky to think that the graft was masking some
> problem, but is it worse than not having the affected packages at all?
> Were things actually not working while the graft was in place? What do
> you think?
>
> [0] https://lists.gnu.org/archive/html/guix-devel/2021-01/msg00292.html

Checking this for the next release (1.2.1) since it is something that an
user from the scientific field could expect, “guix weather
--display-missing” indicates that there is not substitute for vtk@6 but
there is one for vtk@8.  With commit 6bed29b and building locally with
--check I get:

  /gnu/store/3lp7nisflgwv19ahs281z6bc233lpnhh-vtk-8.2.0

reproducibly.

However, vtk@6 fails to build.  The only package depending on vtk@6 is
itk-snap.  Maybe it is worth to try to build it with vtk@8 and remove
vtk@6.  I do not know.


Cheers,
simon