MDEV-38688 UpdateXML should retuln xmltype.

type_handler changed for the UpdateXML.

Author: Alexey Botchkov

plugin/type_xmltype/mysql-test/type_xmltype/type_xmltype.result

@@ -219,4 +219,11 @@ CREATE SEQUENCE s;
 CREATE TABLE t ( a XMLTYPE DEFAULT NEXTVAL(s));
 ERROR HY000: Cannot cast 'bigint' as 'xmltype' in assignment of `test`.`t`.`a`
 DROP SEQUENCE s;
+CREATE TABLE t1 AS SELECT UpdateXML('<a><b>ccc</b><d></d></a>', '/a', '<e>fff</e>') as x;
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `x` xmltype CHARACTER SET latin1 COLLATE latin1_swedish_ci DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
+DROP TABLE t1;
 # End of 11.8 tests

plugin/type_xmltype/mysql-test/type_xmltype/type_xmltype.test

@@ -151,5 +151,9 @@ CREATE SEQUENCE s;
 CREATE TABLE t ( a XMLTYPE DEFAULT NEXTVAL(s));
 DROP SEQUENCE s;
 
+CREATE TABLE t1 AS SELECT UpdateXML('<a><b>ccc</b><d></d></a>', '/a', '<e>fff</e>') as x;
+SHOW CREATE TABLE t1;
+DROP TABLE t1;
+
 --echo # End of 11.8 tests
 

sql/item_xmlfunc.cc

@@ -3072,6 +3072,26 @@ String *Item_func_xml_extractvalue::val_str(String *str)
 }
 
 
+const Type_handler *Item_func_xml_update::xml_handler= NULL;
+
+
+bool Item_func_xml_update::fix_length_and_dec(THD *thd)
+{
+  static LEX_CSTRING name= {STRING_WITH_LEN("XMLTYPE")};
+
+  if (!xml_handler)
+    xml_handler= Type_handler::handler_by_name(thd, name);
+
+  return Item_xml_str_func::fix_length_and_dec(thd);
+}
+
+
+const Type_handler *Item_func_xml_update::type_handler() const
+{
+  return xml_handler ? xml_handler : Item_xml_str_func::type_handler();
+}
+
+
 bool Item_func_xml_update::collect_result(String *str,
                                           const MY_XML_NODE *cut,
                                           const String *replace)

sql/item_xmlfunc.h

@@ -157,6 +157,10 @@ class Item_func_xml_update: public Item_xml_str_func
     static LEX_CSTRING name= {STRING_WITH_LEN("updatexml") };
     return name;
   }
+  static const Type_handler *xml_handler;
+  const Type_handler *type_handler() const override;
+  bool fix_length_and_dec(THD *thd) override;
+
   String *val_str(String *) override;
   Item *do_get_copy(THD *thd) const override
   { return get_item_copy<Item_func_xml_update>(thd, this); }