if [ -e "/tmp/IS_EMPTY_REPO" ]; then
    _log "It's empty repo. skip pull source"
    exit 0
fi

if [ "$PLUGIN_NEED_MERGE" = true ]; then
  _log "pull source due to need merge..."

  _log "git cat-file -e \"${PLUGIN_SOURCE_SHA}^{commit}\""
  git cat-file -e "${PLUGIN_SOURCE_SHA}^{commit}"
  local NEED_FETCH=$?

  if [ "$NEED_FETCH" == 0 ]; then
    _log "no need to fetch"
  else
    local OPTIONS="-v --progress --force --no-recurse-submodules"
    local REFMAP="--refmap=+refs/heads/*:refs/remotes/origin/*"

    if [[ "$PLUGIN_SOURCE_REF" =~ ^refs/tags/.* ]]; then
      REFMAP="--refmap=+refs/tags/*:refs/tags/*"
    fi
    
    if [ "$PLUGIN_SOURCE_URL" == "$PLUGIN_TARGET_URL" ]; then
      _log "git fetch $OPTIONS $REFMAP origin \"${PLUGIN_SOURCE_REF}\""
      git fetch $OPTIONS $REFMAP origin "${PLUGIN_SOURCE_REF}"
      ret=$?; [ $ret -ne 0 ] && exit $ret;
    else
      _log "git fetch  $OPTIONS \"${PLUGIN_SOURCE_URL}\" \"${PLUGIN_SOURCE_REF}\""
      git fetch $OPTIONS "${PLUGIN_SOURCE_URL}" "${PLUGIN_SOURCE_REF}"
      ret=$?; [ $ret -ne 0 ] && exit $ret;
    fi
  fi

  _log "git cat-file -e \"${PLUGIN_SOURCE_SHA:-FETCH_HEAD}^{commit}\""
  git cat-file -e "${PLUGIN_SOURCE_SHA:-FETCH_HEAD}^{commit}"
  if ! [ "$?" == 0 ]; then
    echo -e "${PLUGIN_SOURCE_URL} 的引用 ${PLUGIN_SOURCE_REF} 不包含所需提交 ${PLUGIN_SOURCE_SHA} "
    exit 1
  fi

  if [ "$PLUGIN_SOURCE_URL" == "$PLUGIN_TARGET_URL" ] && [[ "$PLUGIN_SOURCE_REF" =~ ^refs/heads/.* ]]; then
    _log "git update-ref \"${PLUGIN_SOURCE_REF}\" \"${PLUGIN_SOURCE_SHA:-FETCH_HEAD}\""
    git update-ref "${PLUGIN_SOURCE_REF}" "${PLUGIN_SOURCE_SHA:-FETCH_HEAD}"
  fi

  _log "git merge --quiet --no-edit \"${PLUGIN_SOURCE_SHA:-FETCH_HEAD}\""
  git merge --quiet --no-edit "${PLUGIN_SOURCE_SHA:-FETCH_HEAD}"
  ret=$?; [ $ret -ne 0 ] && exit $ret;
fi