MDEV-4564 ALTER on a temporary table generates an audit event

mysql-test/suite/plugins/r/audit_null.result

@@ -44,6 +44,7 @@ insert t2 values ('2020-10-09');
 select * from t2;
 a
 2020-10-09
+alter table t2 add column b int;
 drop table t2;
 explain select distinct * from t2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -77,8 +78,8 @@ root[root] @ localhost []	test.t1 : read
 root[root] @ localhost []	>> rename table t1 to t2
 root[root] @ localhost []	test.t1 : rename to test.t2
 root[root] @ localhost []	>> alter table t2 add column b int
-root[root] @ localhost []	test.t2 : alter
 root[root] @ localhost []	test.t2 : read
+root[root] @ localhost []	test.t2 : alter
 root[root] @ localhost []	>> create definer=testuser@localhost view v1 as select t2.a+1, t2_copy.a+2 from t2, t2 as t2_copy
 root[root] @ localhost []	test.t2 : read
 root[root] @ localhost []	test.t2 : read
@@ -89,6 +90,7 @@ root[root] @ localhost []	>> drop view v1
 root[root] @ localhost []	>> create temporary table t2 (a date)
 root[root] @ localhost []	>> insert t2 values ('2020-10-09')
 root[root] @ localhost []	>> select * from t2
+root[root] @ localhost []	>> alter table t2 add column b int
 root[root] @ localhost []	>> drop table t2
 root[root] @ localhost []	>> explain select distinct * from t2
 root[root] @ localhost []	test.t2 : read

mysql-test/suite/plugins/t/audit_null.test

@@ -38,6 +38,7 @@ drop view v1;
 create temporary table t2 (a date);
 insert t2 values ('2020-10-09');
 select * from t2;
+alter table t2 add column b int; # MDEV-4565 ALTER on a temporary table generates an audit event
 drop table t2;
 
 # internal temp table generates no audit events

sql/sql_table.cc

@@ -6064,13 +6064,16 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
 
   mysql_ha_rm_tables(thd, table_list);
 
-  mysql_audit_alter_table(thd, table_list);
-
   /* DISCARD/IMPORT TABLESPACE is always alone in an ALTER TABLE */
   if (alter_info->tablespace_op != NO_TABLESPACE_OP)
+  {
+    mysql_audit_alter_table(thd, table_list);
+
     /* Conditionally writes to binlog. */
-    DBUG_RETURN(mysql_discard_or_import_tablespace(thd,table_list,
-						   alter_info->tablespace_op));
+    bool ret= mysql_discard_or_import_tablespace(thd,table_list,
+                                                 alter_info->tablespace_op);
+    DBUG_RETURN(ret);
+  }
 
   /*
     Code below can handle only base tables so ensure that we won't open a view.
@@ -6262,6 +6265,9 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
     my_error(ER_ILLEGAL_HA, MYF(0), table_name);
     goto err;
   }
+
+  if (table->s->tmp_table == NO_TMP_TABLE)
+    mysql_audit_alter_table(thd, table_list);
   
   thd_proc_info(thd, "setup");
   if (!(alter_info->flags & ~(ALTER_RENAME | ALTER_KEYS_ONOFF)) &&