MDEV-5445 Server crashes in Item_func_like::fix_fields on LIKE ExtractValue(..)

backporting from the main 10.0

modified:
  mysql-test/r/func_like.result
  mysql-test/t/func_like.test
  sql/item_cmpfunc.cc

mysql-test/r/func_like.result

@@ -188,3 +188,15 @@ DROP TABLE t1, t2;
 SELECT '' LIKE '1' ESCAPE COUNT(1);
 ERROR HY000: Incorrect arguments to ESCAPE
 End of 5.1 tests
+#
+# Start of 10.0 tests
+#
+#
+# MDEV-5445 Server crashes in Item_func_like::fix_fields on LIKE ExtractValue(..)
+#
+SELECT 'a' LIKE REPEAT('',0);
+'a' LIKE REPEAT('',0)
+0
+SELECT 'a' LIKE EXTRACTVALUE('bar','qux');
+'a' LIKE EXTRACTVALUE('bar','qux')
+0

mysql-test/t/func_like.test

@@ -133,3 +133,13 @@ DROP TABLE t1, t2;
 SELECT '' LIKE '1' ESCAPE COUNT(1);
 
 --echo End of 5.1 tests
+
+--echo #
+--echo # Start of 10.0 tests
+--echo #
+
+--echo #
+--echo # MDEV-5445 Server crashes in Item_func_like::fix_fields on LIKE ExtractValue(..)
+--echo #
+SELECT 'a' LIKE REPEAT('',0);
+SELECT 'a' LIKE EXTRACTVALUE('bar','qux');

sql/item_cmpfunc.cc

@@ -5020,7 +5020,7 @@ bool Item_func_like::fix_fields(THD *thd, Item **ref)
         turboBM_compute_bad_character_shifts();
         DBUG_PRINT("info",("done"));
       }
-      use_sampling= ((*first == wild_many || *first == wild_one) && len > 2);
+      use_sampling= (len > 2 && (*first == wild_many || *first == wild_one));
     }
   }
   return FALSE;