R SIG Debian - Apr 2021 - c2d4u: missing dependency for r-cran-gert and r-cran-v8 on bionic

A user has reported, and I have confirmed, that r-cran-gert from c2d4u
is uninstallable on bionic because it is compiled against a version of
libgit2 that is not included with c2d4u:

 # apt-get install r-cran-gert
 The following packages have unmet dependencies:
   r-cran-gert : Depends: libgit2-27 (>= 0.26.0) but it is not installable
  E: Unable to correct problems, you have held broken packages.
>From the c2d4u buildlog I can see that it is compiling r-cran-gert
against the libgit2 backports from ppa:cran/libgit2. So I think the
easiest solution is to put a copy of that libgit2 into c2d4u.

The same seems to hold for r-cran-v8.

The problem does not exist for ubuntu:focal because here the stock
versions of libgit2 and libv8 are sufficient and we do not provide ppa
backports.

On 4/8/21 6:18 AM, Jeroen Ooms wrote:
> A user has reported, and I have confirmed, that r-cran-gert from c2d4u
> is uninstallable on bionic because it is compiled against a version of
> libgit2 that is not included with c2d4u:
> 
>   # apt-get install r-cran-gert
>   The following packages have unmet dependencies:
>     r-cran-gert : Depends: libgit2-27 (>= 0.26.0) but it is not
installable
>    E: Unable to correct problems, you have held broken packages.
> 
>  From the c2d4u buildlog I can see that it is compiling r-cran-gert
> against the libgit2 backports from ppa:cran/libgit2. So I think the
> easiest solution is to put a copy of that libgit2 into c2d4u.
> 
> The same seems to hold for r-cran-v8.
> 
> The problem does not exist for ubuntu:focal because here the stock
> versions of libgit2 and libv8 are sufficient and we do not provide ppa
> backports.
Jeroen,

In this case, I view this aspect of Launchpad as a feature.  Maintaining 
c2d4u takes up enough of my time, so if another PPA exists that allows a 
package to be built on c2d4u, then I am going to utilize it.  Same way I 
would encourage anyone wanting to add additional R packages to Launchpad 
use my RRutter and c2d4u PPAs as a starting point.  No need to reinvent 
the wheel.

c2d4u has dependencies on five other PPAs.  They are listed on the front 
page of the PPA under "Technical details about this PPA" and I
strongly
encourage people using c2d4u to install these as well.

Michael