MDEV-12772 Add Field::get_typelib() and Item::get_typelib()

sql/field.h

@@ -1289,6 +1289,7 @@ class Field: public Value_source
   uint fill_cache_field(struct st_cache_field *copy);
   virtual bool get_date(MYSQL_TIME *ltime, ulonglong fuzzydate);
   bool get_time(MYSQL_TIME *ltime) { return get_date(ltime, TIME_TIME_ONLY); }
+  virtual TYPELIB *get_typelib() const { return NULL; }
   virtual CHARSET_INFO *charset(void) const { return &my_charset_bin; }
   virtual CHARSET_INFO *charset_for_protocol(void) const
   { return binary() ? &my_charset_bin : charset(); }
@@ -3547,6 +3548,7 @@ class Field_enum :public Field_str {
   /* enum and set are sorted as integers */
   CHARSET_INFO *sort_charset(void) const { return &my_charset_bin; }
   uint decimals() const { return 0; }
+  TYPELIB *get_typelib() const { return typelib; }
 
   virtual uchar *pack(uchar *to, const uchar *from, uint max_length);
   virtual const uchar *unpack(uchar *to, const uchar *from,

sql/item.cc

@@ -9986,21 +9986,14 @@ void Item_type_holder::get_full_info(Item *item)
   if (Item_type_holder::real_type_handler() == &type_handler_enum ||
       Item_type_holder::real_type_handler() == &type_handler_set)
   {
-    if (item->type() == Item::SUM_FUNC_ITEM &&
-        (((Item_sum*)item)->sum_func() == Item_sum::MAX_FUNC ||
-         ((Item_sum*)item)->sum_func() == Item_sum::MIN_FUNC))
-      item = ((Item_sum*)item)->get_arg(0);
+    TYPELIB *item_typelib= item->get_typelib();
     /*
       We can have enum/set type after merging only if we have one enum|set
       field (or MIN|MAX(enum|set field)) and number of NULL fields
     */
-    DBUG_ASSERT((enum_set_typelib &&
-                 item->real_type_handler() == &type_handler_null) ||
-                (!enum_set_typelib &&
-                 item->real_item()->type() == Item::FIELD_ITEM &&
-                 (item->real_type_handler() == &type_handler_enum ||
-                  item->real_type_handler() == &type_handler_set) &&
-                 ((Field_enum*)((Item_field *) item->real_item())->field)->typelib));
+    DBUG_ASSERT(item->real_type_handler() == &type_handler_null ||
+                (enum_set_typelib && !item_typelib) ||
+                (!enum_set_typelib && item_typelib));
     if (!enum_set_typelib)
     {
       enum_set_typelib= ((Field_enum*)((Item_field *) item->real_item())->field)->typelib;

sql/item.h

@@ -787,6 +787,7 @@ class Item: public Value_source,
   {
     return type_handler()->max_display_length(this);
   }
+  virtual TYPELIB *get_typelib() const { return NULL; }
   Item_cache* get_cache(THD *thd) const
   {
     return type_handler()->Item_get_cache(thd, this);
@@ -2682,6 +2683,7 @@ class Item_field :public Item_ident
       return &type_handler_null;
     return field->type_handler();
   }
+  TYPELIB *get_typelib() const { return field->get_typelib(); }
   enum_monotonicity_info get_monotonicity_info() const
   {
     return MONOTONIC_STRICT_INCREASING;
@@ -4321,6 +4323,11 @@ class Item_ref :public Item_ident
   {
     return ref ? (*ref)->real_item() : this;
   }
+  TYPELIB *get_typelib() const
+  {
+    return ref ? (*ref)->get_typelib() : NULL;
+  }
+
   bool walk(Item_processor processor, bool walk_subquery, void *arg)
   { 
     if (ref && *ref)

sql/item_sum.h

@@ -1044,6 +1044,7 @@ class Item_sum_hybrid :public Item_sum, public Type_handler_hybrid_field_type
   }
   const Type_handler *type_handler() const
   { return Type_handler_hybrid_field_type::type_handler(); }
+  TYPELIB *get_typelib() const { return args[0]->get_typelib(); }
   void update_field();
   void min_max_update_str_field();
   void min_max_update_real_field();