In TRUNCATE TABLE, MySQL may call innobase_xa_prepare() even though there is no active transaction because it was committed in ha_innobase::delete_all_rows(); in innobase_xa_prepare() InnoDB starts then a new transaction; let us adjust the trx->active_trans flag accordingly


sql/ha_innodb.cc:
  In TRUNCATE TABLE, MySQL may call innobase_xa_prepare() even though there is no active transaction because it was committed in ha_innobase::delete_all_rows(); in innobase_xa_prepare() InnoDB starts then a new transaction; let us adjust the trx->active_trans flag accordingly