From 8642d23b6a1ef75d9120ba0871de2c183feee7db Mon Sep 17 00:00:00 2001
From: "igor@olga.mysql.com" <>
Date: Wed, 13 Dec 2006 21:08:25 -0800
Subject: [PATCH] Fixed bug #25027. Blocked evaluation of constant objects of
 the classes Item_func_is_null and Item_is_not_null_test at the prepare phase
 in the cases when the objects used subqueries.

---
 mysql-test/r/ps.result | 7 +++++++
 mysql-test/t/ps.test   | 7 ++++++-
 sql/item_cmpfunc.cc    | 6 +++---
 sql/item_cmpfunc.h     | 3 ++-
 sql/sql_lex.cc         | 1 +
 5 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/mysql-test/r/ps.result b/mysql-test/r/ps.result
index b5a9367c985..000a9317b8d 100644
--- a/mysql-test/r/ps.result
+++ b/mysql-test/r/ps.result
@@ -1528,5 +1528,12 @@ a
 1
 2
 DEALLOCATE PREPARE stmt;
+PREPARE stmt FROM 'SELECT a FROM t1 WHERE (SELECT b FROM t2 limit ?) IS NULL';
+SET @arg=1;
+EXECUTE stmt USING @arg;
+a
+1
+2
+DEALLOCATE PREPARE stmt;
 DROP TABLE t1,t2;
 End of 5.0 tests.
diff --git a/mysql-test/t/ps.test b/mysql-test/t/ps.test
index 9386436a1fd..f6de2a40efa 100644
--- a/mysql-test/t/ps.test
+++ b/mysql-test/t/ps.test
@@ -1577,8 +1577,13 @@ SELECT a FROM t1 WHERE (SELECT b FROM t2) IS NULL;
 PREPARE stmt FROM 'SELECT a FROM t1 WHERE (SELECT b FROM t2) IS NULL';
 
 EXECUTE stmt;
-
 DEALLOCATE PREPARE stmt;
+
+PREPARE stmt FROM 'SELECT a FROM t1 WHERE (SELECT b FROM t2 limit ?) IS NULL';
+SET @arg=1;
+EXECUTE stmt USING @arg;
+DEALLOCATE PREPARE stmt;
+
 DROP TABLE t1,t2;
 
 --echo End of 5.0 tests.
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 29fa049b6c4..0a7cbbb51cb 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -2990,7 +2990,7 @@ longlong Item_func_isnull::val_int()
     Handle optimization if the argument can't be null
     This has to be here because of the test in update_used_tables().
   */
-  if (!used_tables_cache)
+  if (!used_tables_cache && !with_subselect)
     return cached_value;
   return args[0]->is_null() ? 1: 0;
 }
@@ -2999,7 +2999,7 @@ longlong Item_is_not_null_test::val_int()
 {
   DBUG_ASSERT(fixed == 1);
   DBUG_ENTER("Item_is_not_null_test::val_int");
-  if (!used_tables_cache)
+  if (!used_tables_cache && !with_subselect)
   {
     owner->was_null|= (!cached_value);
     DBUG_PRINT("info", ("cached :%ld", (long) cached_value));
@@ -3026,7 +3026,7 @@ void Item_is_not_null_test::update_used_tables()
   else
   {
     args[0]->update_used_tables();
-    if (!(used_tables_cache=args[0]->used_tables()))
+    if (!(used_tables_cache=args[0]->used_tables()) && !with_subselect)
     {
       /* Remember if the value is always NULL or never NULL */
       cached_value= (longlong) !args[0]->is_null();
diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h
index acad1e51bc9..faeee0d5567 100644
--- a/sql/item_cmpfunc.h
+++ b/sql/item_cmpfunc.h
@@ -1028,7 +1028,8 @@ public:
     else
     {
       args[0]->update_used_tables();
-      if ((const_item_cache= !(used_tables_cache= args[0]->used_tables())))
+      if ((const_item_cache= !(used_tables_cache= args[0]->used_tables())) &&
+          !with_subselect)
       {
 	/* Remember if the value is always NULL or never NULL */
 	cached_value= (longlong) args[0]->is_null();
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index f5ec0c1161d..3de842c8551 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -1903,6 +1903,7 @@ void st_select_lex_unit::set_limit(SELECT_LEX *sl)
 {
   ha_rows select_limit_val;
 
+  DBUG_ASSERT(! thd->stmt_arena->is_stmt_prepare());
   select_limit_val= (ha_rows)(sl->select_limit ? sl->select_limit->val_uint() :
                                                  HA_POS_ERROR);
   offset_limit_cnt= (ha_rows)(sl->offset_limit ? sl->offset_limit->val_uint() :