Bug#43668: Wrong comparison and MIN/MAX for YEAR(2)

MySQL manual describes values of the YEAR(2) field type as follows:
values 00 - 69 mean 2000 - 2069 years and values 70 - 99 mean 1970 - 1999
years. MIN/MAX and comparison functions was comparing them as int values
thus producing wrong result.

Now the Arg_comparator class is extended with compare_year function which
performs correct comparison of the YEAR type.
The Item_sum_hybrid class now uses Item_cache and Arg_comparator objects to
correctly calculate its value.
To allow Arg_comparator to use func_name() function for Item_func and Item_sum
objects the func_name declaration is moved to the Item_result_field class.
A helper function is_owner_equal_func is added to the Arg_comparator class.
It checks whether the Arg_comparator object owner is the <=> function or not.
A helper function setup is added to the Item_sum_hybrid class. It sets up
cache item and comparator.

1 files changed, 2 insertions, 2 deletions

diff --git a/sql/item_geofunc.cc b/sql/item_geofunc.cc
index a34204b7181..9b01f77c9a1 100644
--- a/sql/item_geofunc.cc
+++ b/sql/item_geofunc.cc
@@ -506,8 +506,8 @@ err:
 longlong Item_func_spatial_rel::val_int()
 {
   DBUG_ASSERT(fixed == 1);
-  String *res1= args[0]->val_str(&tmp_value1);
-  String *res2= args[1]->val_str(&tmp_value2);
+  String *res1= args[0]->val_str(&cmp.value1);
+  String *res2= args[1]->val_str(&cmp.value2);
   Geometry_buffer buffer1, buffer2;
   Geometry *g1, *g2;
   MBR mbr1, mbr2;