Post merge fix

mysql-test/r/func_gconcat.result

@@ -616,7 +616,7 @@ insert into t1 values (1,repeat('a',255)),(2,repeat('b',255));
 select f2,group_concat(f1) from t1 group by f2;
 Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
 def	test	t1	t1	f2	f2	253	255	255	Y	0	0	8
-def					group_concat(f1)	252	400	1	Y	128	0	63
+def					group_concat(f1)	253	400	1	Y	128	0	63
 f2	group_concat(f1)
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa	1
 bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb	2

sql/item_func.cc

@@ -380,10 +380,7 @@ Field *Item_func::tmp_table_field(TABLE *t_arg)
     res= new Field_double(max_length, maybe_null, name, t_arg, decimals);
     break;
   case STRING_RESULT:
-    if (max_length/collation.collation->mbmaxlen > CONVERT_IF_BIGGER_TO_BLOB)
-      res= new Field_blob(max_length, maybe_null, name, t_arg, collation.collation);
-    else
-      res= new Field_string(max_length, maybe_null, name, t_arg, collation.collation);
+    res= make_string_field(t_arg);
     break;
   case DECIMAL_RESULT:
     res= new Field_new_decimal(my_decimal_precision_to_length(decimal_precision(),

sql/item_sum.cc

@@ -377,12 +377,12 @@ Field *Item_sum::create_tmp_field(bool group, TABLE *table,
   case INT_RESULT:
     return new Field_longlong(max_length,maybe_null,name,table,unsigned_flag);
   case STRING_RESULT:
-    if (max_length > 255 && convert_blob_length)
+    if (max_length/collation.collation->mbmaxlen > 255 && convert_blob_length)
       return new Field_varstring(convert_blob_length, maybe_null,
                                  name, table,
                                  collation.collation);
     return make_string_field(table);
-  case DECIMAL_RESULT:
+case DECIMAL_RESULT:
     return new Field_new_decimal(max_length, maybe_null, name, table,
                                  decimals, unsigned_flag);
   case ROW_RESULT:

sql/item_sum.h

@@ -1121,10 +1121,10 @@ class Item_func_group_concat : public Item_sum
   virtual Item_result result_type () const { return STRING_RESULT; }
   enum_field_types field_type() const
   {
-    if (max_length/collation.collation->mbmaxlen > CONVERT_IF_BIGGER_TO_BLOB)
+    if (max_length/collation.collation->mbmaxlen > CONVERT_IF_BIGGER_TO_BLOB )
       return FIELD_TYPE_BLOB;
     else
-      return MYSQL_TYPE_VAR_STRING;
+      return MYSQL_TYPE_VARCHAR;
   }
   void clear();
   bool add();

sql/sql_select.cc

@@ -8245,20 +8245,13 @@ static Field *create_tmp_field_from_item(THD *thd, Item *item, TABLE *table,
     if ((type= item->field_type()) == MYSQL_TYPE_DATETIME ||
         type == MYSQL_TYPE_TIME || type == MYSQL_TYPE_DATE)
       new_field= item->tmp_table_field_from_field_type(table);
-    else if (item->max_length/item->collation.collation->mbmaxlen >
-             CONVERT_IF_BIGGER_TO_BLOB)
-    {
-      if (convert_blob_length)
-        new_field= new Field_varstring(convert_blob_length, maybe_null,
-                                       item->name, table,
-                                       item->collation.collation);
-      else
-        new_field= new Field_blob(item->max_length, maybe_null, item->name,
-                                  table, item->collation.collation);
-    }
+    else if (item->max_length/item->collation.collation->mbmaxlen > 255 &&
+             convert_blob_length)
+      new_field= new Field_varstring(convert_blob_length, maybe_null,
+                                     item->name, table,
+                                     item->collation.collation);
     else
-      new_field= new Field_string(item->max_length, maybe_null, item->name, 
-                                  table, item->collation.collation);
+      new_field= item->make_string_field(table);
     break;
   case DECIMAL_RESULT:
     new_field= new Field_new_decimal(item->max_length, maybe_null, item->name,