MDEV-15630 uuid() function evaluates at wrong time in query

mysql-test/r/func_misc.result

@@ -572,6 +572,17 @@ N	AVG
 0	NULL
 drop table t1;
 #
+# MDEV-15630 uuid() function evaluates at wrong time in query
+#
+CREATE TABLE t1 (id INT);
+INSERT INTO t1 VALUES (1),(2),(3);
+SELECT COUNT(1), UUID() as uid FROM t1 GROUP BY uid;
+COUNT(1)	uid
+1	xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+1	xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+1	xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+DROP TABLE t1;
+#
 # End of 5.5 tests
 #
 SELECT NAME_CONST('a', -(1 OR 2)) OR 1;

mysql-test/t/func_misc.test

@@ -596,6 +596,18 @@ AND 57813X540X1723 = 'Test';
 
 drop table t1;
 
+
+--echo #
+--echo # MDEV-15630 uuid() function evaluates at wrong time in query
+--echo #
+
+CREATE TABLE t1 (id INT);
+INSERT INTO t1 VALUES (1),(2),(3);
+--replace_column 2 xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+SELECT COUNT(1), UUID() as uid FROM t1 GROUP BY uid;
+DROP TABLE t1;
+
+
 --echo #
 --echo # End of 5.5 tests
 --echo #

sql/item_strfunc.h

@@ -997,6 +997,7 @@ class Item_func_uuid: public Item_str_func
                   DERIVATION_COERCIBLE, MY_REPERTOIRE_ASCII);
     fix_char_length(MY_UUID_STRING_LENGTH);
   }
+  table_map used_tables() const { return RAND_TABLE_BIT; }
   const char *func_name() const{ return "uuid"; }
   String *val_str(String *);
   bool check_vcol_func_processor(uchar *int_arg)