[R-sig-Fedora] R 4.0.0

[Iñaki Ucar]

On Mon, 11 May 2020 at 16:29, Tom Callaway <tcallawa using redhat.com> wrote:
>
> Hmmm. That seems like a rather heavy dependency, given that I think we've
> only been forced to do rebuilds for everything as a result of 4.0.0 and
> 3.4.0.

That's just coincidence, because if you browse old NEWS, you can see
"packages [doing this or that] need to be re(-)installed" here and
there if most minor versions: maybe there wasn't any of such packages
in Fedora, maybe a mass rebuild or an update fixed the issue before
anyone noticed... It's just that we don't have any mechanism to detect
that unless a user complains.

> Does anyone know if upstream has any sort of commitment to ABI here that we
> could depend on (e.g. only breaking on major versions, never minor) ?

AFAIK, there's this commitment only for patch versions. In fact, the
path for the personal library is:

~/R/x86_64-redhat-linux-gnu-library/<major>.<minor>/

so, when you install a new minor version, you don't have any package
in your personal library. Most of the time, for many packages, it just
works if you copy the old packages into the new folder, but many times
things break and reinstallation is needed. And this may happen for
compiled packages, but also for non-compiled ones (e.g.: "Packages
defining S4 classes with the above S3/S4 classes as slots should be
reinstalled", in R 3.3.0).

So maybe we should streamline mass rebuild of R packages, and do it
for all minor updates. The virtual provide you proposed will force us
to do that, and will prevent breakages and complaints.

-- 
Iñaki Úcar