Re: R 3.0.0 and required rebuilds of all reverse Depends: of R

[Josselin Mouette <joss@debian.org>]

Le dimanche 31 mars 2013 à 13:35 -0500, Dirk Eddelbuettel a écrit : 
> That is why we have a meta-variable
> 
>   ${R:Depends}
> 
> in Depends: which gets filled by the R version that compiling the package,
> currently 3.0.0~20130330-1. And which prevents the migration.
> 
> The same scheme worked before so I am not convinced we need something more
> complicated or formal.  

I don’t understand how you can say it “worked before”.
Let’s say you backport a R package from wheezy to squeeze (something we
tried recently at work). The new R will install without a dependency
problem, and… all modules will stop working.

> Testing is fine, but within unstable the transition has to be done.

Testing is not fine. The new R version could migrate to testing without
the new modules, and testing would be broken. Furthermore, incorrect
dependencies, including across upgrades between stable versions, are
generally considered RC.

There are reasons why other interpreters have complex dependency
schemes: previously to avoid that. Not only your reverse dependencies
should only depend on the *sufficient* version of R (in this case,
certainly not the R version used to compile the package, which will lead
to transition blockades to testing), but they should stop installing
when the version of R becomes incompatible, and so far nothing
guarantees that.

Perl has a perlapi-X.Y virtual package to avoid that.
Python generates python (<< X.Y) dependencies to avoid that.
There are tons of similar schemes used across the Debian archive to
avoid such problems, from virtual packages, through autogenerated
dependencies, to package renames.

It’s OK if you don’t know the best way to do that for your package. This
mailing list is here to ask for advice. But I don’t understand how a
developer who was clearly not born yesterday can knowingly break so many
packages, without adding appropriate Breaks, without coordinating with
the release team, and in the final stage of a freeze.

I’d really appreciate if you could think twice next time, before
uploading such a big change.

Thanks,
-- 
 .''`.      Josselin Mouette
: :' :
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