Fixed bug mdev-4336.

When iterating over a list of conditions using List_iterator
the function remove_eq_conds should skip all predicates that
replace a condition from the list. Otherwise it can come to
an infinite recursion. 

1 files changed, 17 insertions, 0 deletions

diff --git a/mysql-test/t/join_outer.test b/mysql-test/t/join_outer.test
index 69c08cd54bd..8c0ee82e1fa 100644
--- a/mysql-test/t/join_outer.test
+++ b/mysql-test/t/join_outer.test
@@ -1359,4 +1359,21 @@ ORDER BY t1.b;
 
 DROP TABLE t1,t2;
 
+--echo #
+--echo # Bug mdev-4336: LEFT JOIN with disjunctive 
+--echo #                <non-nullable datetime field> IS NULL in WHERE 
+--echo #                causes a hang and eventual crash   
+--echo #
+
+CREATE TABLE t1 (
+  id int(11) NOT NULL,
+  modified datetime NOT NULL,
+  PRIMARY KEY (id)
+);
+
+SELECT a.* FROM t1 a LEFT JOIN t1 b ON a.id = b.id 
+  WHERE a.modified > b.modified or b.modified IS NULL;
+
+DROP TABLE t1;
+
 SET optimizer_switch=@save_optimizer_switch;