Bug#40650: dpkg: Show diff when upgrading a conffile

[<daniel@bluegreen.dhis.org>]

Package: dpkg
Version: 1.4.1.3
Severity: wishlist

  Hello,

  When a modified conffile is updated, dpkg shows a prompt with the options
(if I remember this correctly): "Y/N/Z".  I generally use the opportunity to
execute the command 'diff -u conffile conffile.dpkg-dist |& less' and see what
would change if I entered "Y".  It would be incredibly useful if there were a
"D" option which executed this command automatically, and however pasta-like
dpkg's code is, I imagine that the following pseudocode would work:
  if (userchoice == 'D')
    {
      char *temp=malloc(200+2*strlen(conffilename));
      sprintf("diff -u %s %s.dpkg-dist 2>&1 | less",temp);
      system(temp);
      free(temp);
    }

  Daniel

-- System Information
Debian Release: potato
Kernel Version: Linux bluegreen 2.2.10 #2 Mon Jun 14 10:03:47 EDT 1999 i586 unknown

Versions of the packages dpkg depends on:
ii  libc6           2.1.1-12       GNU C Library: Shared libraries and timezone
ii  libncurses4     4.2-3.2        Shared libraries for terminal handling
ii  libstdc++2.9-gl 2.91.66-2      The GNU stdc++ library (EGCS version)