Bug #7498 User variable SET saves SIGNED BIGINT as UNSIGNED BIGINT

- Add unsigned flag to user_var_entry, used when 'type' is INT_RESULT
- Propagate unsigned flag from the query executed by Item_single_row_subselect


mysql-test/r/user_var.result:
  Update test results
mysql-test/t/user_var.test:
  Add test case
sql/item_func.cc:
  Add unsigned_flag to user_var_entry. Used when 'type' is INT_RESULT
  Pass unsigned_flag to 'update_hash' if type is INT_RESULT
sql/item_func.h:
  Removed unused variable save_buff
  Add parameter unsigned_arg to 'update_hash'
sql/item_subselect.cc:
  Propagate unsigned_flag to Item_singlerow_subselect from the items in the select to the cached items.
sql/sql_class.h:
  Add unsigned_flag to user_var_entry. Used when 'type' is INT_RESULT

1 files changed, 31 insertions, 0 deletions

diff --git a/mysql-test/t/user_var.test b/mysql-test/t/user_var.test
index e1b23a1782f..58c52b59a5a 100644
--- a/mysql-test/t/user_var.test
+++ b/mysql-test/t/user_var.test
@@ -171,3 +171,34 @@ set @first_var= cast(NULL as CHAR);
 create table t1 select @first_var;
 show create table t1;
 drop table t1;
+
+#
+# Bug #7498 User variable SET saves SIGNED BIGINT as UNSIGNED BIGINT
+#
+
+# First part, set user var to large number and select it
+set @a=18446744071710965857;
+select @a;
+
+# Second part, set user var from large number in table
+# then select it
+CREATE TABLE `bigfailure` (
+  `afield` BIGINT UNSIGNED NOT NULL
+);
+INSERT INTO `bigfailure` VALUES (18446744071710965857);
+SELECT * FROM bigfailure;
+select * from (SELECT afield FROM bigfailure) as b;
+select * from bigfailure where afield = (SELECT afield FROM bigfailure);
+select * from bigfailure where afield = 18446744071710965857;
+# This is fixed in 5.0, to be uncommented there
+#select * from bigfailure where afield = '18446744071710965857';
+select * from bigfailure where afield = 18446744071710965856+1;
+
+SET @a := (SELECT afield FROM bigfailure);
+SELECT @a;
+SET @a := (select afield from (SELECT afield FROM bigfailure) as b);
+SELECT @a;
+SET @a := (select * from bigfailure where afield = (SELECT afield FROM bigfailure));
+SELECT @a;
+
+drop table bigfailure;