MDEV-33392 Server crashes when using RANDOM_BYTES function and GROUP BY clause...

MDEV-33392 Server crashes when using RANDOM_BYTES function and GROUP BY clause on a column with a negative value

Item_func_random_bytes did not set its NULL-ability flag.

mysql-test/main/func_str.result

@@ -5460,3 +5460,37 @@ Warning	1292	Truncated incorrect BINARY(2) value: '...random bytes...'
 #
 # End of 10.10 tests
 #
+#
+# Start of 10.11 tests
+#
+#
+# MDEV-33392 Server crashes when using RANDOM_BYTES function and GROUP BY clause on a column with a negative value
+#
+SET sql_mode='';
+CREATE TABLE t1 (a VARCHAR(255)) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (9494),(9495),(9496),(9497),(9498),(9499),(9500),(9501),(9502),(9503);
+SELECT RANDOM_BYTES (-1) f1,a f2 FROM t1 GROUP BY f1,f2;
+f1	f2
+NULL	9494
+NULL	9495
+NULL	9496
+NULL	9497
+NULL	9498
+NULL	9499
+NULL	9500
+NULL	9501
+NULL	9502
+NULL	9503
+CREATE TABLE t2 AS SELECT RANDOM_BYTES (-1) f1,a f2 FROM t1 GROUP BY f1,f2;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `f1` binary(0) DEFAULT NULL,
+  `f2` varchar(255) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
+DROP TABLE t2;
+DROP TABLE t1;
+SET sql_mode=DEFAULT;
+#
+# End of 10.11 tests
+#

mysql-test/main/func_str.test

@@ -2435,3 +2435,25 @@ select "a" in ("abc", (convert(random_bytes(8) ,binary(2))));
 --echo #
 --echo # End of 10.10 tests
 --echo #
+
+--echo #
+--echo # Start of 10.11 tests
+--echo #
+
+--echo #
+--echo # MDEV-33392 Server crashes when using RANDOM_BYTES function and GROUP BY clause on a column with a negative value
+--echo #
+
+SET sql_mode='';
+CREATE TABLE t1 (a VARCHAR(255)) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (9494),(9495),(9496),(9497),(9498),(9499),(9500),(9501),(9502),(9503);
+SELECT RANDOM_BYTES (-1) f1,a f2 FROM t1 GROUP BY f1,f2;
+CREATE TABLE t2 AS SELECT RANDOM_BYTES (-1) f1,a f2 FROM t1 GROUP BY f1,f2;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+DROP TABLE t1;
+SET sql_mode=DEFAULT;
+
+--echo #
+--echo # End of 10.11 tests
+--echo #

sql/item_strfunc.cc

@@ -1509,6 +1509,7 @@ String *Item_func_sformat::val_str(String *res)
 
 bool Item_func_random_bytes::fix_length_and_dec(THD *thd)
 {
+  set_maybe_null();
   used_tables_cache|= RAND_TABLE_BIT;
   if (args[0]->can_eval_in_optimize())
   {