bzr commit into mysql-5.1-bugteam branch (sergefp:2751) Bug#37822

[Sergey Petrunia]

#At file:///home/spetrunia/dev/mysql-5.1-bug37822/ based on
revid:aelkin@stripped

 2751 Sergey Petrunia	2009-01-28
      BUG#37822: Correlated subquery with IN and IS UNKNOWN provides wrong result
      Item_in_optimizer::is_null() evaluated "NULL IN (SELECT ...)" to NULL regardless of 
      whether subquery produced any records, this was a documented limitation.
       
      The limitation has been removed (see bugs 8804, 24085, 24127) now
      Item_in_optimizer::val_int() correctly handles all cases with NULLs. Make 
      Item_in_optimizer::is_null() invoke val_int() to return correct values for 
      "NULL IN (SELECT ...)".
modified:
  sql/item_cmpfunc.cc

per-file messages:
  sql/item_cmpfunc.cc
    BUG#37822: Correlated subquery with IN and IS UNKNOWN provides wrong result
    Item_in_optimizer::is_null() evaluated "NULL IN (SELECT ...)" to NULL 
    regardless of whether subquery produced any records, this was a documented limitation.

    
    The limitation has been removed (see bugs 8804, 24085, 24127) now
    Item_in_optimizer::val_int() correctly handles all cases with NULLs. Make 
    Item_in_optimizer::is_null() invoke val_int() to return correct values for 
    "NULL IN (SELECT ...)".
=== modified file 'sql/item_cmpfunc.cc'
--- a/sql/item_cmpfunc.cc	2009-01-15 18:11:25 +0000
+++ b/sql/item_cmpfunc.cc	2009-01-28 15:17:59 +0000
@@ -1623,8 +1623,8 @@ void Item_in_optimizer::cleanup()
 
 bool Item_in_optimizer::is_null()
 {
-  cache->store(args[0]);
-  return (null_value= (cache->null_value || args[1]->is_null()));
+  val_int();
+  return null_value;
 }