Bug #31155 gis types in union'd select cause crash.

We use get_geometry_type() call to decide the exact type
of a geometry field to be created (POINT, POLYGON etc)
Though this function was only implemented for few items.
In the bug's case we need to call this function for the
Item_sum instance, where it was not implemented, what is
the reason of the crash.
Fixed by implementing virtual Item::get_geometry_type(),
so it can be called for any Item.

1 files changed, 3 insertions, 4 deletions

diff --git a/sql/item_geofunc.h b/sql/item_geofunc.h
index 9c7970f9e53..e99510f762f 100644
--- a/sql/item_geofunc.h
+++ b/sql/item_geofunc.h
@@ -33,7 +33,6 @@ public:
   void fix_length_and_dec();
   enum_field_types field_type() const  { return MYSQL_TYPE_GEOMETRY; }
   Field *tmp_table_field(TABLE *t_arg);
-  virtual int get_geometry_type() const;
   bool is_null() { (void) val_int(); return null_value; }
 };
 
@@ -92,7 +91,7 @@ public:
   Item_func_centroid(Item *a): Item_geometry_func(a) {}
   const char *func_name() const { return "centroid"; }
   String *val_str(String *);
-  int get_geometry_type() const;
+  Field::geometry_type get_geometry_type() const;
 };
 
 class Item_func_envelope: public Item_geometry_func
@@ -101,7 +100,7 @@ public:
   Item_func_envelope(Item *a): Item_geometry_func(a) {}
   const char *func_name() const { return "envelope"; }
   String *val_str(String *);
-  int get_geometry_type() const;
+  Field::geometry_type get_geometry_type() const;
 };
 
 class Item_func_point: public Item_geometry_func
@@ -111,7 +110,7 @@ public:
   Item_func_point(Item *a, Item *b, Item *srid): Item_geometry_func(a, b, srid) {}
   const char *func_name() const { return "point"; }
   String *val_str(String *);
-  int get_geometry_type() const;
+  Field::geometry_type get_geometry_type() const;
 };
 
 class Item_func_spatial_decomp: public Item_geometry_func