Bug#19955: unsigned bigint used as signed with MOD function

Problem:  When we have a really large number (between 2^63 and 2^64)
as the left side of the mod operator, it gets improperly corerced
into a signed value.

Solution:  Added check to see if the "negative" number is really
positive, and if so, cast it.


mysql-test/r/bigint.result:
  Added test case result
mysql-test/t/bigint.test:
  Added test case
sql/item_func.cc:
  Added check to see if we have an unsigned number that looks like a
  signed number.

1 files changed, 9 insertions, 0 deletions

diff --git a/mysql-test/t/bigint.test b/mysql-test/t/bigint.test
index 35cda11646a..6c1229db83f 100644
--- a/mysql-test/t/bigint.test
+++ b/mysql-test/t/bigint.test
@@ -278,4 +278,13 @@ select * from t1 where bigint_col=17666000000000000000;
 select * from t1 where bigint_col='17666000000000000000';
 drop table t1;
 
+--echo
+--echo bug 19955 -- mod is signed with bigint
+
+select cast(10000002383263201056 as unsigned) mod 50 as result;
+
+create table t1 (c1 bigint unsigned);
+insert into t1 values (10000002383263201056);
+select c1 mod 50 as result from t1;
+drop table t1;