Do we really need versioned depends r-base-core including Debian revision

[Andreas Tille <andreas@an3as.eu>]

Hi,

since I ended up with an R package which I was not (yet) able to install
on my system I checked the dependencies created by dh-r.  The reason
was that my pbuilder environment includes
   http://incoming.debian.org/debian-buildd
and so I ended up with a versioned Dependency of a just created
r-cran-knitr package which had:

   Depends: r-base-core (>= 3.6.1-5), r-api-3.5

while 

$ apt-cache policy r-base-core
r-base-core:
  Installiert:           3.6.1-4
  Installationskandidat: 3.6.1-4
  Versionstabelle:
     3.6.1-5 50
         50 http://incoming.debian.org/debian-buildd buildd-unstable/main amd64 Packages
 *** 3.6.1-4 100
         50 http://httpredir.debian.org/debian unstable/main amd64 Packages
         50 http://ftp.debian.org/debian unstable/main amd64 Packages
        100 /var/lib/dpkg/status

Well, this does not lead to a problem in the long run since r-cran-knitr
will become available after r-base-core and the issue is void for normal
users.  However, it made me wonder (again) why we really inject that
strict versioned Build-Depends.  I assumed we intended to settle just
with r-api - and here I'm wondering why r-api remains at 3.6.  Shouldn't
this rather be r-api-3.6?

Moreover I wonder why we need the r-base-core dependency at all if we
would have the (correct!) r-api version.  And if we really need the
r-base-core dependency whether it wouln't be more sensible to at least
strip the Debian release and may be we can settle with the first two
digits (matching the api version).  I've digged in dh-R code and found
this three year old code of Gordon in dh/R.pm:

22fd80b9 (Gordon Ball   2016-09-04 12:28:57 +0200 149)     chomp(my $rbase_version = qx/dpkg-query -W -f='\${Version}' r-base-dev/);
22fd80b9 (Gordon Ball   2016-09-04 12:28:57 +0200 150)     say "I: Building using R version $rbase_version";
^023f5eb (Gordon Ball   2016-09-01 16:28:08 +0200 151) 
22fd80b9 (Gordon Ball   2016-09-04 12:28:57 +0200 152)     chomp(my $rapi_version = qx/dpkg-query -W -f='\${Provides}' r-base-core | grep -o 'r-api[^, ]*'/);
22fd80b9 (Gordon Ball   2016-09-04 12:28:57 +0200 153)     say "I: R API version: $rapi_version";

Is this just forgotten code that is just not adapted to the needs we
have these days?

Kind regards

      Andreas.

-- 
http://fam-tille.de