MDEV-17711 Assertion `arena_for_set_stmt== 0' failed in...

MDEV-17711 Assertion `arena_for_set_stmt== 0' failed in LEX::set_arena_for_set_stmt upon SET STATEMENT

restore SET STATEMENT variables between statements in a multi-statement

mysql-test/main/set_statement.result

@@ -1271,4 +1271,16 @@ SET sql_mode=ORACLE;
 SET STATEMENT max_statement_time=30 FOR DELETE FROM mysql.user where user = 'unknown';
 SET sql_mode=default;
 SET STATEMENT max_statement_time=30 FOR DELETE FROM mysql.user where user = 'unknown';
+#
+# MDEV-17711 Assertion `arena_for_set_stmt== 0' failed in LEX::set_arena_for_set_stmt upon SET STATEMENT
+#
+set rand_seed1=1, rand_seed2=2;
+set statement rand_seed1=4 for select 2, @@rand_seed1, @@rand_seed2;
+set statement rand_seed2=5 for select 3, @@rand_seed1, @@rand_seed2 $
+2	@@rand_seed1	@@rand_seed2
+2	4	2
+3	@@rand_seed1	@@rand_seed2
+3	1	5
+#
 # End of 10.4 tests
+#

mysql-test/main/set_statement.test

@@ -1191,4 +1191,16 @@ SET STATEMENT max_statement_time=30 FOR DELETE FROM mysql.user where user = 'unk
 SET sql_mode=default;
 SET STATEMENT max_statement_time=30 FOR DELETE FROM mysql.user where user = 'unknown';
 
+--echo #
+--echo # MDEV-17711 Assertion `arena_for_set_stmt== 0' failed in LEX::set_arena_for_set_stmt upon SET STATEMENT
+--echo #
+
+--delimiter $
+set rand_seed1=1, rand_seed2=2;
+set statement rand_seed1=4 for select 2, @@rand_seed1, @@rand_seed2;
+set statement rand_seed2=5 for select 3, @@rand_seed1, @@rand_seed2 $
+--delimiter ;
+
+--echo #
 --echo # End of 10.4 tests
+--echo #

sql/sql_parse.cc

@@ -1901,6 +1901,8 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
         MYSQL_QUERY_DONE(thd->is_error());
       }
 
+      thd->lex->restore_set_statement_var();
+
 #if defined(ENABLED_PROFILING)
       thd->profiling.finish_current_query();
       thd->profiling.start_new_query("continuing");