bk commit into 5.0 tree (igor:1.2597) BUG#27545

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ChangeSet@stripped, 2007-12-07 23:36:58-08:00, igor@stripped +3 -0
  Fixed bug #27545.
  Both arguments of the function NAME_CONST must be constant expressions.
  This constraint is checked in the Item_name_const::fix_fields method. 
  Yet if the argument of the function was not a constant expression no
  error message was reported. As a result the client hanged waiting for a
  response.
  Now the function Item_name_const::fix_fields reports an error message
  when any of the additional context conditions imposed on the function
  NAME_CONST is not satisfied. 

  mysql-test/r/func_misc.result@stripped, 2007-12-07 23:36:53-08:00, igor@stripped +5 -0
    Added a test case for bug #26545.

  mysql-test/t/func_misc.test@stripped, 2007-12-07 23:36:53-08:00, igor@stripped +13 -0
    Added a test case for bug #26545.

  sql/item.cc@stripped, 2007-12-07 23:36:53-08:00, igor@stripped +7 -7
    Fixed bug #27545.
    Both arguments of the function NAME_CONST must be constant expressions.
    This constraint is checked in the Item_name_const::fix_fields method. 
    Yet if the argument of the function was not a constant expression no
    error message was reported. As a result the client hanged waiting for a
    response.
    Now the function Item_name_const::fix_fields reports an error message
    when any of the additional context conditions imposed on the function
    NAME_CONST is not satisfied. 

diff -Nrup a/mysql-test/r/func_misc.result b/mysql-test/r/func_misc.result
--- a/mysql-test/r/func_misc.result	2007-10-09 02:36:00 -07:00
+++ b/mysql-test/r/func_misc.result	2007-12-07 23:36:53 -08:00
@@ -207,4 +207,9 @@ test
 SELECT NAME_CONST('test', 'test');
 test
 test
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (5), (2);
+SELECT NAME_CONST(x,2) FROM (SELECT a x FROM t1) t;
+ERROR HY000: The 'NAME_CONST' syntax is reserved for purposes internal to the MySQL
server
+DROP TABLE t1;
 End of 5.0 tests
diff -Nrup a/mysql-test/t/func_misc.test b/mysql-test/t/func_misc.test
--- a/mysql-test/t/func_misc.test	2007-10-09 02:36:00 -07:00
+++ b/mysql-test/t/func_misc.test	2007-12-07 23:36:53 -08:00
@@ -204,5 +204,18 @@ SELECT NAME_CONST('test', 1.0);
 SELECT NAME_CONST('test', -1.0);
 SELECT NAME_CONST('test', 'test');
 
+#
+# Bug #27545: erroneous usage of NAME_CONST with a name as the first parameter 
+#             resolved against a column name of a derived table hangs the client
+#
+
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (5), (2);
+
+--error ER_RESERVED_SYNTAX
+SELECT NAME_CONST(x,2) FROM (SELECT a x FROM t1) t;
+
+DROP TABLE t1;
+
 --echo End of 5.0 tests
 
diff -Nrup a/sql/item.cc b/sql/item.cc
--- a/sql/item.cc	2007-11-20 09:18:20 -08:00
+++ b/sql/item.cc	2007-12-07 23:36:53 -08:00
@@ -1221,14 +1221,14 @@ bool Item_name_const::fix_fields(THD *th
   s.length(0);
 
   if (value_item->fix_fields(thd, &value_item) ||
-      name_item->fix_fields(thd, &name_item))
+      name_item->fix_fields(thd, &name_item) ||
+      !value_item->const_item() ||
+      !name_item->const_item() ||
+      !(item_name= name_item->val_str(&s))) // Can't have a NULL name 
+  {
+    my_error(ER_RESERVED_SYNTAX, MYF(0), "NAME_CONST");
     return TRUE;
-  if (!(value_item->const_item() && name_item->const_item()))
-    return TRUE;
-
-  if (!(item_name= name_item->val_str(&s)))
-    return TRUE; /* Can't have a NULL name */
-
+  }
   set_name(item_name->ptr(), (uint) item_name->length(), system_charset_info);
   max_length= value_item->max_length;
   decimals= value_item->decimals;