Fix for bug#22397 Events: crash with procedure which alters events

  
ALTER EVENT in stored procedure body led to a crash during the
procedure call. Affected was only ALTER EVENT which changed the
interval of the event. No problems with AT, STARTS, ENDS and so on.

mysql-test/r/events_bugs.result

@@ -213,4 +213,17 @@ create event e_53 on schedule every 5 second starts (select s1 from ttx) do drop
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'select s1 from ttx) do drop table t' at line 1
 create event e_53 on schedule every 5 second ends (select s1 from ttx) do drop table t;
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'select s1 from ttx) do drop table t' at line 1
+drop event if exists e_16;
+drop procedure if exists p_16;
+create event e_16 on schedule every 1 second do set @a=5;
+create procedure p_16 () alter event e_16 on schedule every @a second;
+set @a = null;
+call p_16();
+ERROR HY000: Incorrect INTERVAL value: 'NULL'
+call p_16();
+ERROR HY000: Incorrect INTERVAL value: 'NULL'
+set @a= 6;
+call p_16();
+drop procedure p_16;
+drop event e_16;
 drop database events_test;

mysql-test/t/events_bugs.test

@@ -234,4 +234,23 @@ create event e_53 on schedule every 5 second ends (select s1 from ttx) do drop t
 # END   - BUG#16394: Events: Crash if schedule contains SELECT
 #
 
+#
+# START - BUG#22397: Events: crash with procedure which alters events
+#
+--disable_warnings
+drop event if exists e_16;
+drop procedure if exists p_16;
+--enable_warnings
+create event e_16 on schedule every 1 second do set @a=5;
+create procedure p_16 () alter event e_16 on schedule every @a second;
+set @a = null;
+--error ER_WRONG_VALUE
+call p_16();
+--error ER_WRONG_VALUE
+call p_16();
+set @a= 6;
+call p_16();
+
+drop procedure p_16;
+drop event e_16;
 drop database events_test;

sql/event_data_objects.cc

@@ -353,7 +353,7 @@ Event_parse_data::init_interval(THD *thd)
   DBUG_RETURN(0);
 
 wrong_value:
-  report_bad_value("INTERVAL", item_execute_at);
+  report_bad_value("INTERVAL", item_expression);
   DBUG_RETURN(ER_WRONG_VALUE);
 }