Bug#550584: Initial triggers patch and tracking of highest kernel

[Loïc Minier <lool@dooz.org>]

On Wed, Mar 09, 2011, Steve McIntyre wrote:
> Neither do I *for definite*, but I know that other tools that rely on
> kernel ABI have been thrown by the sort order of "trunk" vs "1", "2",
> etc. so I'm raising it early in case it matters.

 My first reaction was that it was basically the problem of the people
 using this name in the first place, but then I figured that if
 flash-kernel just did what grub does, nobody would complain.  Turns out
 grub seems to have special casing for trunk!

 it uses version_find_latest() below which calls version_test_gt(),
 sounds like exactly what we need, and version_test_gt() starts by
 transforming trunk versions to use ~.

version_test_gt ()
{
  local sedexp="s/[^-]*-//;s/[._-]\(pre\|rc\|test\|git\|old\|trunk\)/~\1/g"
  local a=`echo $1 | sed -e "$sedexp"`
  local b=`echo $2 | sed -e "$sedexp"`
  local cmp=gt
  if [ "x$b" = "x" ] ; then
    return 0
  fi
  case $a:$b in
    *.old:*.old) ;;
    *.old:*) a=`echo -n $a | sed -e s/\.old$//` ; cmp=gt ;;
    *:*.old) b=`echo -n $b | sed -e s/\.old$//` ; cmp=ge ;;
  esac
  dpkg --compare-versions "$a" $cmp "$b"
  return $?
}

version_find_latest ()
{
  local a=""
  for i in $@ ; do
    if version_test_gt "$i" "$a" ; then
      a="$i"
    fi
  done
  echo "$a"
}

-- 
Loïc Minier