MDEV-34683 Types mismatch when cloning items causes debug assertion

New runtime type diagnostic (MDEV-34490) has detected that classes
Item_func_eq, Item_default_value and Item_date_literal_for_invalid_dates
incorrectly return an instance of its ancestor classes when being cloned.
This commit fixes that.

Additionally, it fixes a bug at Item_func_case_simple::do_build_clone()
which led to an endless loop of cloning functions calls.

Reviewer: Oleksandr Byelkin <sanja@mariadb.com>

mysql-test/main/item_types.result

@@ -14,3 +14,17 @@ SELECT * FROM t1 JOIN t2 ON t1.c=t2.c WHERE t1.c<=>5;
 c	c
 DROP TABLE t1, t2;
 SET optimizer_switch=default;
+#
+# MDEV-34683 Types mismatch when cloning items causes debug assertion
+#
+CREATE TABLE t1 (a date);
+CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t1;
+SELECT a FROM v1 WHERE a IN ('a', 'b', 'c');
+a
+CREATE VIEW v2 AS SELECT '' as a;
+SELECT * FROM v2 WHERE a='' AND CASE '' WHEN '' THEN '' ELSE a END='';
+a
+
+DROP TABLE t1;
+DROP VIEW v1, v2;
+# End of 10.5 tests

mysql-test/main/item_types.test

@@ -13,3 +13,21 @@ SELECT * FROM t1 JOIN t2 ON t1.c=t2.c WHERE t1.c<=>5;
 DROP TABLE t1, t2;
 
 SET optimizer_switch=default;
+
+--echo #
+--echo # MDEV-34683 Types mismatch when cloning items causes debug assertion
+--echo #
+
+CREATE TABLE t1 (a date);
+CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t1;
+--disable_warnings
+SELECT a FROM v1 WHERE a IN ('a', 'b', 'c');
+--enable_warnings
+
+CREATE VIEW v2 AS SELECT '' as a;
+SELECT * FROM v2 WHERE a='' AND CASE '' WHEN '' THEN '' ELSE a END='';
+
+DROP TABLE t1;
+DROP VIEW v1, v2;
+
+--echo # End of 10.5 tests

sql/item.h

@@ -5225,6 +5225,9 @@ class Item_date_literal_for_invalid_dates: public Item_date_literal
     cached_time.copy_to_mysql_time(ltime);
     return (null_value= false);
   }
+  Item *do_get_copy(THD *thd) const override
+  { return get_item_copy<Item_date_literal_for_invalid_dates>(thd, this); }
+  Item *do_build_clone(THD *thd) const override { return get_copy(thd); }
 };
 
 
@@ -6699,7 +6702,9 @@ class Item_default_value : public Item_field
     description
   */
   bool associate_with_target_field(THD *thd, Item_field *field) override;
-
+  Item *do_get_copy(THD *thd) const override
+  { return get_item_copy<Item_default_value>(thd, this); }
+  Item* do_build_clone(THD *thd) const override { return get_copy(thd); }
 private:
   bool tie_field(THD *thd);
 };

sql/item_cmpfunc.cc

@@ -1814,6 +1814,16 @@ longlong Item_func_eq::val_int()
 }
 
 
+Item *Item_func_eq::do_build_clone(THD *thd) const
+{
+  /*
+    Clone the parent and cast to the child class since there is nothing
+    specific for Item_func_eq
+  */
+  return (Item_func_eq*) Item_bool_rowready_func2::do_build_clone(thd);
+}
+
+
 /** Same as Item_func_eq, but NULL = NULL. */
 
 bool Item_func_equal::fix_length_and_dec()

sql/item_cmpfunc.h

@@ -765,6 +765,7 @@ class Item_func_eq :public Item_bool_rowready_func2
   friend class  Arg_comparator;
   Item *do_get_copy(THD *thd) const override
   { return get_item_copy<Item_func_eq>(thd, this); }
+  Item *do_build_clone(THD *thd) const override;
 };
 
 class Item_func_equal final :public Item_bool_rowready_func2
@@ -2324,7 +2325,7 @@ class Item_func_case_simple: public Item_func_case,
   Item *do_build_clone(THD *thd) const override
   {
     Item_func_case_simple *clone= (Item_func_case_simple *)
-                                  Item_func_case::build_clone(thd);
+                                  Item_func_case::do_build_clone(thd);
     uint ncases= when_count();
     if (clone && clone->Predicant_to_list_comparator::init_clone(thd, ncases))
       return NULL;