Question on libapt-pkg-dev changes in 2.5.0

[Dirk Eddelbuettel <edd@debian.org>]

Hi apt team,

A while back I wrote a small interface from R to apt, using libapt-pkg-dev
(and Rcpp for the R/C++ glue).

It is a package in the R ecosystem and on CRAN.

Now, as of version 2.5.0, it stopped compiling because

   In file included from buildDepends.cpp:26:
   In file included from /usr/include/apt-pkg/debsrcrecords.h:14:
   In file included from /usr/include/apt-pkg/srcrecords.h:15:
   /usr/include/apt-pkg/hashes.h:19:10: fatal error: 'apt-pkg/tagfile-keys.h' file not found
   #include <apt-pkg/tagfile-keys.h>
            ^~~~~~~~~~~~~~~~~~~~~~~~
   1 error generated.

I can work around the 'fail to compile' issue by no longer (unconditionally)
compiling that file buildDepends.  But I would of course like to restore the
ability to browse (source) dependencies and reverse dependencies.  Is still
supported?  I see in your changelog that

   * Document tagfile-keys.h as internal to apt

but am a little confused that debsrcrecords.h has an unconditional

   #include <apt-pkg/tagfile-keys.h>

Is there a reference or test client which retrieves this info under the
updated API?  In essence I 'just' do (in R) something like this for a
function returning build-depends

   buildDepends("^apt$")                    

   > v <- buildDepends("^apt$")
   > v[1:10]
    [1] "cmake"            "debhelper-compat"
    [3] "docbook-xml"      "docbook-xsl"     
    [5] "dpkg-dev"         "gettext"         
    [7] "googletest"       "libgtest-dev"    
    [9] "libbz2-dev"       "libdb-dev"       
   > 

which returns a std::vector<std::string> of package names, and similarly a
dumper of source record

   > res <- capture.output( showSrc("^apt$") )
   > res[1:4]
   [1] "--apt"
   [2] "Package: apt"
   [3] "Format: 3.0 (native)"
   [4] "Binary: apt, libapt-pkg6.0, apt-doc, libapt-pkg-dev, libapt-pkg-doc, apt-utils, apt-transport-https"
   > 

where here I just capture the stdout to filter it.

My (now repaired to allow compilation) code is here

   https://github.com/eddelbuettel/rcppapt/blob/master/src/buildDepends.cpp

and you can see that there is not _that_ much going -- just collecting
vectors of result strings, really -- but I would need to know which data
structure to access.

I can switch from 'debsrcrecord.h' to 'srcrecords.h' but how I replace
debSrcRecordParser which only seems to be defined in debsrcrecords.h which I
can no longer include.

I may just be missing a small nudge so any help would be appreciated.

Cheers, Dirk

-- 
dirk.eddelbuettel.com | @eddelbuettel | edd@debian.org