MDEV-6601 Assertion `!thd->in_active_multi_stmt_transa ction() ||...

MDEV-6601 Assertion `!thd->in_active_multi_stmt_transa ction() || thd->in_multi_stmt_transaction_mode()' failed on executing a stored procedure with commit

Don't restore the whole of thd->server_status after a routine invocation,
only restore SERVER_STATUS_CURSOR_EXISTS and SERVER_STATUS_LAST_ROW_SENT,
as --ps --embedded needs.
In particular, don't restore SERVER_STATUS_IN_TRANS.

mysql-test/r/sp-bugs.result

@@ -268,3 +268,9 @@ END $$
 CALL test_5531(1);
 DROP PROCEDURE test_5531;
 DROP TABLE t1;
+create procedure sp() begin
+commit;
+end|
+start transaction;
+call sp();
+drop procedure sp;

mysql-test/t/sp-bugs.test

@@ -285,3 +285,16 @@ DELIMITER ;$$
 CALL test_5531(1);
 DROP PROCEDURE test_5531;
 DROP TABLE t1;
+
+#
+# MDEV-6601 Assertion `!thd->in_active_multi_stmt_transa ction() || thd->in_multi_stmt_transaction_mode()' failed on executing a stored procedure with commit
+#
+delimiter |;
+create procedure sp() begin
+  commit;
+end|
+delimiter ;|
+start transaction;
+call sp();
+drop procedure sp;
+

sql/sp_head.cc

@@ -1224,6 +1224,8 @@ sp_head::execute(THD *thd, bool merge_da_on_success)
   Item_change_list old_change_list;
   String old_packet;
   uint old_server_status;
+  const uint status_backup_mask= SERVER_STATUS_CURSOR_EXISTS |
+                                 SERVER_STATUS_LAST_ROW_SENT;
   Reprepare_observer *save_reprepare_observer= thd->m_reprepare_observer;
   Object_creation_ctx *saved_creation_ctx;
   Warning_info *saved_warning_info;
@@ -1358,7 +1360,7 @@ sp_head::execute(THD *thd, bool merge_da_on_success)
     It is probably safe to use same thd->convert_buff everywhere.
   */
   old_packet.swap(thd->packet);
-  old_server_status= thd->server_status;
+  old_server_status= thd->server_status & status_backup_mask;
 
   /*
     Switch to per-instruction arena here. We can do it since we cleanup
@@ -1488,7 +1490,7 @@ sp_head::execute(THD *thd, bool merge_da_on_success)
   thd->spcont->pop_all_cursors(); // To avoid memory leaks after an error
 
   /* Restore all saved */
-  thd->server_status= old_server_status;
+  thd->server_status= (thd->server_status & ~status_backup_mask) | old_server_status;
   old_packet.swap(thd->packet);
   DBUG_ASSERT(thd->change_list.is_empty());
   old_change_list.move_elements_to(&thd->change_list);