MDEV-29357 Assertion (fixed) in Item_func_dayname on INSERT

Restrict vcol_cleanup_expr() in close_thread_tables() to only simple
locked tables mode. Prelocked is cleaned up like normal statement: in
close_thread_table().

mysql-test/suite/vcol/r/vcol_syntax.result

@@ -216,3 +216,21 @@ Warnings:
 Warning	1292	Truncated incorrect DOUBLE value: 'foo'
 Warning	1292	Truncated incorrect DOUBLE value: 'bar'
 drop table t, tmp;
+#
+# MDEV-29357 Assertion (fixed) in Item_func_dayname on INSERT
+#
+set sql_mode='';
+create table t (c1 blob ,c2 int,c3 char(10) as (dayname (c2)));
+create trigger tr before insert on t for each row set new.c2=0;
+insert into t values (0, 0, 0);
+Warnings:
+Warning	1906	The value specified for generated column 'c3' in table 't' has been ignored
+Warning	1292	Incorrect datetime value: '0' for column `test`.`t`.`c2` at row 1
+Warning	1292	Incorrect datetime value: '0' for column `test`.`t`.`c2` at row 1
+insert into t values (1, 1, 1);
+Warnings:
+Warning	1906	The value specified for generated column 'c3' in table 't' has been ignored
+Warning	1292	Incorrect datetime value: '1' for column `test`.`t`.`c2` at row 1
+Warning	1292	Incorrect datetime value: '0' for column `test`.`t`.`c2` at row 1
+drop trigger tr;
+drop table t;

mysql-test/suite/vcol/t/vcol_syntax.test

@@ -173,3 +173,15 @@ select * from t;
 
 # cleanup
 drop table t, tmp;
+
+--echo #
+--echo # MDEV-29357 Assertion (fixed) in Item_func_dayname on INSERT
+--echo #
+set sql_mode='';
+create table t (c1 blob ,c2 int,c3 char(10) as (dayname (c2)));
+create trigger tr before insert on t for each row set new.c2=0;
+insert into t values (0, 0, 0);
+insert into t values (1, 1, 1);
+
+drop trigger tr;
+drop table t;

sql/sql_base.cc

@@ -913,7 +913,12 @@ void close_thread_tables(THD *thd)
           !thd->stmt_arena->is_stmt_prepare())
         table->part_info->vers_check_limit(thd);
 #endif
-      table->vcol_cleanup_expr(thd);
+      /*
+        For simple locking we cleanup it here because we don't close thread
+        tables. For prelocking we close it when we do close thread tables.
+      */
+      if (thd->locked_tables_mode != LTM_PRELOCKED)
+        table->vcol_cleanup_expr(thd);
     }
 
     /* Detach MERGE children after every statement. Even under LOCK TABLES. */