Bug #24595937: INCORRECT BEHAVIOR WHEN LOADING DATA TO VIEW

Issue:
------
While using the LOAD statement to insert data into an
updateable view, the check to verify whether a column
is actually updatable is missing.

Solution for 5.5 and 5.6:
-------------------------
For a view whose column-list in specified in the LOAD
command, this check is not performed. This fix adds the
check.

This is a partial backport of Bug#21097485.

Solution for 5.7 and trunk:
---------------------------
For a view whose column-list is specified in the LOAD
command, this check is already performed. This fix adds the
same check when no column-list is specified.

mysql-test/r/loaddata.result

@@ -316,7 +316,7 @@ FIELDS ESCAPED BY '\\'
   TERMINATED BY ','
   ENCLOSED BY '"'
   LINES TERMINATED BY '\n' (c0, c2);
-ERROR HY000: Invalid column reference (v2.c0) in LOAD DATA
+ERROR HY000: Column 'c0' is not updatable
 
 LOAD DATA INFILE '../../std_data/bug35469.dat' INTO TABLE v3
 FIELDS ESCAPED BY '\\'

mysql-test/t/loaddata.test

@@ -292,7 +292,7 @@ SELECT * FROM v2;
 DELETE FROM t1;
 
 --echo
---error ER_LOAD_DATA_INVALID_COLUMN
+--error ER_NONUPDATEABLE_COLUMN
 LOAD DATA INFILE '../../std_data/bug35469.dat' INTO TABLE v2
   FIELDS ESCAPED BY '\\'
   TERMINATED BY ','

sql/sql_load.cc

@@ -296,6 +296,24 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
         setup_fields(thd, 0, set_fields, MARK_COLUMNS_WRITE, 0, 0) ||
         check_that_all_fields_are_given_values(thd, table, table_list))
       DBUG_RETURN(TRUE);
+
+    /*
+      Special updatability test is needed because fields_vars may contain
+      a mix of column references and user variables.
+    */
+    Item *item;
+    List_iterator<Item> it(fields_vars);
+    while ((item= it++))
+    {
+      if ((item->type() == Item::FIELD_ITEM ||
+           item->type() == Item::REF_ITEM) &&
+          item->filed_for_view_update() == NULL)
+      {
+        my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), item->name);
+        DBUG_RETURN(true);
+      }
+    }
+
     /*
       Check whenever TIMESTAMP field with auto-set feature specified
       explicitly.