fixed substring() length calculation in case of constant negative argument (BUG#10269)

mysql-test/r/func_str.result:
  Correct length reporting from substring()
mysql-test/t/func_str.test:
  Correct length reporting from substring()
sql/item_strfunc.cc:
  fixed substring() length calculation in case of constant negative argument

1 files changed, 9 insertions, 0 deletions

diff --git a/mysql-test/t/func_str.test b/mysql-test/t/func_str.test
index 36cfac16ff3..9a8ef7c1341 100644
--- a/mysql-test/t/func_str.test
+++ b/mysql-test/t/func_str.test
@@ -541,3 +541,12 @@ SELECT * FROM t1, t2 WHERE num=str;
 SELECT * FROM t1, t2 WHERE num=substring(str from 1 for 6);
 
 DROP TABLE t1,t2;
+
+#
+# Correct length reporting from substring() (BUG#10269)
+#
+create table t1 (b varchar(5));
+insert t1 values ('ab'), ('abc'), ('abcd'), ('abcde');
+select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1;
+select * from (select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1) t;
+drop table t1;