Bug#760936: BLAS: not Multi-Arch safe

[Sébastien Villemot]

Le mardi 09 septembre 2014 à 15:17 +0200, Helmut Grohne a écrit :

> > Given that transitions are now frozen for Jessie, and given that the
> > freeze is less than 2 months ahead, I think that this is too big a
> > change to be implemented now, for several reasons: it involves multiple
> > packages (blas, lapack, atlas, openblas); it needs coordinated changes
> > in those packages, which means that they must all transition to testing
> > at the same time; the change is tricky because it involves lots of code
> > in maintainer scripts, with possible problems on upgrade paths; I will
> > have almost no time in October for Debian.
> 
> I agree that any way to solve this issue involves severe changes, which
> may be unsuitable for jessie. But for jessie we do not have to
> Multi-Arch blas. It suffices to make it Multi-Arch safe.
> 
> > If you come up soon with working patches for these 4 packages, I will do
> > my best to review and upload them. Otherwise I don't think that this
> > move is realistic before the freeze.
> 
> Let me propose another funky workaround for jessie:
> 
> Introduce a new, empty arch:any package (whose sole purpose is to
> exist). Do not mark it as Multi-Arch anything (this is crucial and why
> you cannot reuse things like libc6 or dpkg for this). Then have all blas
> implementations depend on this package.
> 
> Any blas implementation being installed will pull in the new package for
> the architecture. Any other blas implementation will only be installable
> for the same architecture now.
> 
> Even though, this goes through NEW and has to touch at least four
> packages, it does not cause a transition. It also does not cause the
> update-alternatives handling to change. What do you think?

Thanks for suggesting this alternative solution, which I think is a good
compromise for jessie. It is a bit ugly, but I don't see any other way
of forbidding M-A co-installability of two different packages. Hopefully
the ftpmasters won't oppose this. I'll try to implement this soon.

-- 
 .''`.    Sébastien Villemot
: :' :    Debian Developer
`. `'     http://www.dynare.org/sebastien
  `-      GPG Key: 4096R/381A7594

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