From 14ede384fe113fbccd38d9389cdcb5391ca65403 Mon Sep 17 00:00:00 2001
From: unknown <serg@serg.mylan>
Date: Fri, 30 Jan 2004 08:09:42 +0100
Subject: [PATCH] catch accesses to deleted objects double delete bug fixed

sql/sql_list.h:
  catch accesses to deleted objects
sql/sql_union.cc:
  double delete fixed
---
 sql/sql_list.h   | 10 ++++++++--
 sql/sql_union.cc |  1 +
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/sql/sql_list.h b/sql/sql_list.h
index 0972d0341f6..c7faef88358 100644
--- a/sql/sql_list.h
+++ b/sql/sql_list.h
@@ -21,6 +21,12 @@
 
 /* mysql standard class memoryallocator */
 
+#ifdef PEDANTIC_SAFEMALLOC
+#define TRASH(XX,YY) bfill((XX), (YY), 0x8F)
+#else
+#define TRASH(XX,YY) /* no-op */
+#endif
+
 class Sql_alloc
 {
 public:
@@ -34,8 +40,8 @@ public:
   }
   static void *operator new(size_t size, MEM_ROOT *mem_root)
   { return (void*) alloc_root(mem_root, (uint) size); }
-  static void operator delete(void *ptr, size_t size) {} /*lint -e715 */
-  static void operator delete[](void *ptr, size_t size) {}
+  static void operator delete(void *ptr, size_t size) { TRASH(ptr, size); }
+  static void operator delete[](void *ptr, size_t size) { TRASH(ptr, size); }
 #ifdef HAVE_purify
   bool dummy;
   inline Sql_alloc() :dummy(0) {}
diff --git a/sql/sql_union.cc b/sql/sql_union.cc
index 1cb01c6b3ef..226086d0d24 100644
--- a/sql/sql_union.cc
+++ b/sql/sql_union.cc
@@ -445,6 +445,7 @@ int st_select_lex_unit::cleanup()
   if (union_result)
   {
     delete union_result;
+    union_result=0; // Safety
     if (table)
       free_tmp_table(thd, table);
     table= 0; // Safety