null-pointer failure in rb_sort_clb #2471

/**

• @brief Call plugins_types sort callback or sort values by plugin order.
• @PARAM[in] ctx libyang context.
• @PARAM[in] val1 First value to compare.
• @PARAM[in] val2 Second value to compare.
• @return Negative number if val1 < val2,
• @return Zero if val1 == val2,
• @return Positive number if val1 > val2.
  */
  static int
  in (const struct ly_ctx *ctx, const struct lyd_value *val1, const struct lyd_value *val2)
  {
  assert(val1->realtype == val2->realtype);
  return val1->realtype->plugin->sort(ctx, val1, val2);
  }

we met null-poniter failure when using the interface lyds_merge, we find the val1 could be null-pointer. How should we perform a NULL check on the input parameter.

Best wishes,
ciao