update .preinst file

[Herbert Fortes <terberh@gmail.com>]

Hi,

I have to update 4 debian/*.preinst files.

Right now the files are like here[0]:

if dpkg --compare-versions "$2" lt "1.2.4+dfsg1-7" ; then
   rm -rf /usr/share/doc/bogofilter || true
fi


[0] -  https://anonscm.debian.org/git/collab-maint/bogofilter.git/tree/debian/bogofilter.preinst


This approach has problems on an upgrade from Jessie to 
Stretch[1].The recommendation today is to use 'dpkg-maintscript-helper', so
I should change to ("a  real directory  is switched to a symlink"):

[1] - https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=832291

if dpkg-maintscript-helper supports dir_to_symlink 2>/dev/null; then
                dpkg-maintscript-helper dir_to_symlink \
               /usr/share/doc/bogofilter bogofilter 1.2.4+dfsg1-8 bogofilter -- "$@"          
fi

>From the manpage:

"pathname(/usr/share/doc/bogofilter here)  is the absolute name of the old 
directory (the path will be a symlink at the end of the installation) and 
new-target (bogofilter here) is the target of the  new  symlink at pathname. 
It can either be absolute or relative to the directory containing pathname."

But the symlink is created by dh_installdocs[1] already. I just want to remove 
the directory.

[1] - 'dh_installdocs --link-doc=bogofilter-common'

The manpage again:

 COMMANDS AND PARAMETERS
       supports command

       rm_conffile conffile [prior-version [package]]

       mv_conffile old-conffile new-conffile [prior-version [package]]

       symlink_to_dir pathname old-target [prior-version [package]]

       dir_to_symlink pathname new-target [prior-version [package]]


What should I do ?



Regards,
Herbert