message: un-break my sequence
diff: @@ -22,13 +22,14 @@ unique_ptr<CreateSequenceStatement> Transformer::TransformCreateSequence(Node *n
  for_each_cell(cell, stmt->options->head) {
  auto *def_elem = reinterpret_cast<DefElem *>(cell->data.ptr_value);
  string opt_name = string(def_elem->defname);
  - if (def_elem->defaction == DEFELEM_UNSPEC) { // e.g. NO MINVALUE
  +
  + auto val = (postgres::Value *)def_elem->arg;
  + if (def_elem->defaction == DEFELEM_UNSPEC && !val) { // e.g. NO MINVALUE
  continue;
  }
  - assert(def_elem->arg);
  + assert(val);
  if (opt_name == "increment") {
  - auto val = (postgres::Value *)def_elem->arg;
  assert(val->type == T_Integer);
  info.increment = val->val.ival;
  if (info.increment == 0) {
  @@ -42,25 +43,21 @@ unique_ptr<CreateSequenceStatement> Transformer::TransformCreateSequence(Node *n
  info.max_value = numeric_limits<int64_t>::max();
  }
  } else if (opt_name == "minvalue") {
  - auto val = (postgres::Value *)def_elem->arg;
  assert(val->type == T_Integer);
  info.min_value = val->val.ival;
  if (info.increment > 0) {
  info.start_value = info.min_value;
  }
  } else if (opt_name == "maxvalue") {
  - auto val = (postgres::Value *)def_elem->arg;
  assert(val->type == T_Integer);
  info.max_value = val->val.ival;
  if (info.increment < 0) {
  info.start_value = info.max_value;
  }
  } else if (opt_name == "start") {
  - auto val = (postgres::Value *)def_elem->arg;
  assert(val->type == T_Integer);
  info.start_value = val->val.ival;
  } else if (opt_name == "cycle") {
  - auto val = (postgres::Value *)def_elem->arg;
  assert(val->type == T_Integer);
  info.cycle = val->val.ival > 0;
  } else {
  