MDEV-12696 Crash with LOAD XML and non-updatable VIEW column

mysql-test/r/loadxml.result

@@ -123,3 +123,14 @@ col1	col2	col3
 ABC	DEF	NULL
 GHI	NULL	123
 DROP TABLE t1;
+#
+# MDEV-12696 Crash with LOAD XML and non-updatable VIEW column
+#
+CREATE TABLE t1 (c1 TEXT);
+CREATE VIEW v1 AS SELECT CONCAT(c1,'') AS c1, NULL AS c2 FROM t1;
+LOAD XML INFILE '../../std_data/loaddata/mdev12696.xml' INTO TABLE v1 (c1);
+ERROR HY000: Invalid column reference (v1.c1) in LOAD DATA
+LOAD XML INFILE '../../std_data/loaddata/mdev12696.xml' INTO TABLE v1 (c2);
+ERROR HY000: Invalid column reference (v1.c2) in LOAD DATA
+DROP VIEW v1;
+DROP TABLE t1;

mysql-test/std_data/loaddata/mdev12696.xml

+<?xml version="1.0"?>
+
+<resultset statement="SELECT 'test' AS c1, NULL AS c2
+" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <row>
+	<field name="c1">test</field>
+	<field name="c2" xsi:nil="true" />
+  </row>
+</resultset>

mysql-test/t/loadxml.test

@@ -130,3 +130,16 @@ CREATE TABLE t1 (col1 VARCHAR(3), col2 VARCHAR(3), col3 INTEGER);
 LOAD XML INFILE '../../std_data/bug16171518_2.dat' INTO TABLE t1;
 SELECT * FROM t1 ORDER BY col1, col2, col3;
 DROP TABLE t1;
+
+--echo #
+--echo # MDEV-12696 Crash with LOAD XML and non-updatable VIEW column
+--echo #
+
+CREATE TABLE t1 (c1 TEXT);
+CREATE VIEW v1 AS SELECT CONCAT(c1,'') AS c1, NULL AS c2 FROM t1;
+--error ER_LOAD_DATA_INVALID_COLUMN
+LOAD XML INFILE '../../std_data/loaddata/mdev12696.xml' INTO TABLE v1 (c1);
+--error ER_LOAD_DATA_INVALID_COLUMN,
+LOAD XML INFILE '../../std_data/loaddata/mdev12696.xml' INTO TABLE v1 (c2);
+DROP VIEW v1;
+DROP TABLE t1;

sql/item.h

@@ -439,6 +439,19 @@ typedef struct replace_equal_field_arg
   struct st_join_table *context_tab;
 } REPLACE_EQUAL_FIELD_ARG;
 
+
+class Load_data_out_param
+{
+public:
+  Load_data_out_param() { }
+  virtual ~Load_data_out_param() { }
+  virtual void load_data_set_null_value(CHARSET_INFO *cs) = 0;
+  virtual void load_data_set_value(const char *str, uint length,
+                                   CHARSET_INFO *cs) = 0;
+  virtual void load_data_print(THD *thd, String *str) = 0;
+};
+
+
 class Settable_routine_parameter
 {
 public:
@@ -1789,6 +1802,14 @@ class Item: public Value_source,
     delete this;
   }
 
+  virtual Load_data_out_param *get_load_data_out_param() { return 0; }
+  Load_data_out_param *get_load_data_out_param_or_error()
+  {
+    Load_data_out_param *res= get_load_data_out_param();
+    if (!res)
+      my_error(ER_LOAD_DATA_INVALID_COLUMN, MYF(0), full_name());
+    return res;
+  }
   virtual Item_splocal *get_item_splocal() { return 0; }
   virtual Rewritable_query_parameter *get_rewritable_query_parameter()
   { return 0; }

sql/item_func.cc

@@ -5675,14 +5675,15 @@ bool Item_user_var_as_out_param::fix_fields(THD *thd, Item **ref)
 }
 
 
-void Item_user_var_as_out_param::set_null_value(CHARSET_INFO* cs)
+void Item_user_var_as_out_param::load_data_set_null_value(CHARSET_INFO* cs)
 {
   ::update_hash(entry, TRUE, 0, 0, STRING_RESULT, cs, 0 /* unsigned_arg */);
 }
 
 
-void Item_user_var_as_out_param::set_value(const char *str, uint length,
-                                           CHARSET_INFO* cs)
+void Item_user_var_as_out_param::load_data_set_value(const char *str,
+                                                     uint length,
+                                                     CHARSET_INFO* cs)
 {
   ::update_hash(entry, FALSE, (void*)str, length, STRING_RESULT, cs,
                 0 /* unsigned_arg */);
@@ -5717,7 +5718,7 @@ my_decimal* Item_user_var_as_out_param::val_decimal(my_decimal *decimal_buffer)
 }
 
 
-void Item_user_var_as_out_param::print_for_load(THD *thd, String *str)
+void Item_user_var_as_out_param::load_data_print(THD *thd, String *str)
 {
   str->append('@');
   append_identifier(thd, str, name.str, name.length);

sql/item_func.h

@@ -2006,7 +2006,8 @@ class Item_func_get_user_var :public Item_func_user_var,
   in List<Item> and desire to place this code somewhere near other functions
   working with user variables.
 */
-class Item_user_var_as_out_param :public Item
+class Item_user_var_as_out_param :public Item,
+                                  public Load_data_out_param
 {
   LEX_STRING name;
   user_var_entry *entry;
@@ -2021,9 +2022,10 @@ class Item_user_var_as_out_param :public Item
   my_decimal *val_decimal(my_decimal *decimal_buffer);
   /* fix_fields() binds variable name with its entry structure */
   bool fix_fields(THD *thd, Item **ref);
-  void print_for_load(THD *thd, String *str);
-  void set_null_value(CHARSET_INFO* cs);
-  void set_value(const char *str, uint length, CHARSET_INFO* cs);
+  Load_data_out_param *get_load_data_out_param() { return this; }
+  void load_data_print(THD *thd, String *str);
+  void load_data_set_null_value(CHARSET_INFO* cs);
+  void load_data_set_value(const char *str, uint length, CHARSET_INFO* cs);
   enum_field_types field_type() const { return MYSQL_TYPE_DOUBLE; }
   Item *get_copy(THD *thd, MEM_ROOT *mem_root)
   { return get_item_copy<Item_user_var_as_out_param>(thd, mem_root, this); }

sql/sql_load.cc

@@ -431,7 +431,7 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
       else
         tot_length+= field->field_length;
     }
-    else if (item->type() == Item::STRING_ITEM)
+    else if (item->get_load_data_out_param())
       use_vars= 1;
   }
   if (use_blobs && !ex->line_term->length() && !field_term->length())
@@ -814,11 +814,7 @@ static bool write_execute_load_query_log_event(THD *thd, sql_exchange* ex,
       if (item->real_type() == Item::FIELD_ITEM)
         append_identifier(thd, &query_str, item->name, strlen(item->name));
       else
-      {
-        /* Actually Item_user_var_as_out_param despite claiming STRING_ITEM. */
-        DBUG_ASSERT(item->type() == Item::STRING_ITEM);
-        ((Item_user_var_as_out_param *)item)->print_for_load(thd, &query_str);
-      }
+        item->get_load_data_out_param()->load_data_print(thd, &query_str);
     }
     query_str.append(")");
   }
@@ -1062,6 +1058,7 @@ read_sep_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
       uint length;
       uchar *pos;
       Item *real_item;
+      Load_data_out_param *out_param;
 
       if (read_info.read_field())
 	break;
@@ -1104,18 +1101,11 @@ read_sep_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
           }
           /* Do not auto-update this field. */
           field->set_has_explicit_value();
-	}
-        else if (item->type() == Item::STRING_ITEM)
-        {
-          ((Item_user_var_as_out_param *)item)->set_null_value(
-                                                  read_info.read_charset);
         }
+        else if ((out_param= item->get_load_data_out_param_or_error()))
+          out_param->load_data_set_null_value(read_info.read_charset);
         else
-        {
-          my_error(ER_LOAD_DATA_INVALID_COLUMN, MYF(0), item->full_name());
           DBUG_RETURN(1);
-        }
-
 	continue;
       }
 
@@ -1129,16 +1119,11 @@ read_sep_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
         field->store((char*) pos, length, read_info.read_charset);
         field->set_has_explicit_value();
       }
-      else if (item->type() == Item::STRING_ITEM)
-      {
-        ((Item_user_var_as_out_param *)item)->set_value((char*) pos, length,
-                                                        read_info.read_charset);
-      }
+      else if ((out_param= item->get_load_data_out_param_or_error()))
+        out_param->load_data_set_value((const char *) pos, length,
+                                       read_info.read_charset);
       else
-      {
-        my_error(ER_LOAD_DATA_INVALID_COLUMN, MYF(0), item->full_name());
         DBUG_RETURN(1);
-      }
     }
 
     if (thd->is_error())
@@ -1158,6 +1143,7 @@ read_sep_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
 	break;
       for (; item ; item= it++)
       {
+        Load_data_out_param *out_param;
         Item *real_item= item->real_item();
         if (real_item->type() == Item::FIELD_ITEM)
         {
@@ -1183,16 +1169,10 @@ read_sep_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
                               ER_THD(thd, ER_WARN_TOO_FEW_RECORDS),
                               thd->get_stmt_da()->current_row_for_warning());
         }
-        else if (item->type() == Item::STRING_ITEM)
-        {
-          ((Item_user_var_as_out_param *)item)->set_null_value(
-                                                  read_info.read_charset);
-        }
+        else if ((out_param= item->get_load_data_out_param_or_error()))
+          out_param->load_data_set_null_value(read_info.read_charset);
         else
-        {
-          my_error(ER_LOAD_DATA_INVALID_COLUMN, MYF(0), item->full_name());
           DBUG_RETURN(1);
-        }
       }
     }
 
@@ -1288,6 +1268,7 @@ read_xml_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
     
     while ((item= it++))
     {
+      Load_data_out_param *out_param;
       /* If this line is to be skipped we don't want to fill field or var */
       if (skip_lines)
         continue;
@@ -1319,14 +1300,15 @@ read_xml_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
           /* Do not auto-update this field. */
           field->set_has_explicit_value();
         }
+        else if ((out_param= item->get_load_data_out_param_or_error()))
+          out_param->load_data_set_null_value(cs);
         else
-          ((Item_user_var_as_out_param *) item)->set_null_value(cs);
+          DBUG_RETURN(1);
         continue;
       }
 
       if (item->type() == Item::FIELD_ITEM)
       {
-
         Field *field= ((Item_field *)item)->field;
         field->set_notnull();
         if (field == table->next_number_field)
@@ -1334,10 +1316,12 @@ read_xml_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
         field->store((char *) tag->value.ptr(), tag->value.length(), cs);
         field->set_has_explicit_value();
       }
+      else if ((out_param= item->get_load_data_out_param_or_error()))
+        out_param->load_data_set_value((const char *) tag->value.ptr(),
+                                       tag->value.length(), cs);
       else
-        ((Item_user_var_as_out_param *) item)->set_value(
-                                                 (char *) tag->value.ptr(), 
-                                                 tag->value.length(), cs);
+        DBUG_RETURN(1);
+
     }
     
     if (read_info.error)
@@ -1357,6 +1341,7 @@ read_xml_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
       
       for ( ; item; item= it++)
       {
+        Load_data_out_param *out_param;
         if (item->type() == Item::FIELD_ITEM)
         {
           /*
@@ -1371,8 +1356,10 @@ read_xml_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
                               ER_THD(thd, ER_WARN_TOO_FEW_RECORDS),
                               thd->get_stmt_da()->current_row_for_warning());
         }
+        else if ((out_param= item->get_load_data_out_param_or_error()))
+          out_param->load_data_set_null_value(cs);
         else
-          ((Item_user_var_as_out_param *)item)->set_null_value(cs);
+          DBUG_RETURN(1);
       }
     }