#!/bin/bash

extend_bases () {
  shas="$1"
  new="$2"
  for sha in $shas ; do
    [ "$sha" = "$new" ] && continue
    ${DELI_GIT_IS_ANCESTOR_CMD:-git merge-base --is-ancestor} "$sha" "$new"
    res=$?
    case $res in
    0) ;;
    1) echo "$sha" ;;
    *) echo "$0: ancestor finding failed" >&2
       exit 1 ;;
    esac
  done
  old=no
  for sha in $shas ; do
    [ "$sha" = "$new" ] && continue
    ${DELI_GIT_IS_ANCESTOR_CMD:-git merge-base --is-ancestor} "$new" "$sha"
    res=$?
    case $res in
    0) old=yes ; break ;;
    1) ;;
    *) echo "$0: ancestor finding failed" >&2
       exit 1 ;;
    esac
  done
  [ $old = no ] && echo "$new"
}

bases=""

while read sha ; do
  bases=$( extend_bases "$bases" "$sha" )
done

for sha in $bases ; do
  echo "$sha"
done