Bug #56709: Memory leaks at running the 5.1 test suite

Fixed a number of memory leaks discovered by valgrind.

dbug/dbug.c:
  This is actually an addendum to the fix for bug #52629:
  
  - there is no point in limiting the fix to just global
  variables, session ones are also affected.
  - zero all fields when allocating a new 'state' structure so
  that FreeState() does not deal with unitialized data later.
  - add a check for a NULL pointer in DBUGCloseFile()
mysql-test/r/partition_error.result:
  Added a test case for bug #56709.
mysql-test/r/variables_debug.result:
  Added a test case for bug #56709.
mysql-test/t/partition_error.test:
  Added a test case for bug #56709.
mysql-test/t/variables_debug.test:
  Added a test case for bug #56709.
sql/item_timefunc.cc:
  There is no point in declaring 'value' as a member of
  Item_extract and dynamically allocating memory for it in
  Item_extract::fix_length_and_dec(), since this string is only
  used as a temporary storage in Item_extract::val_int().
sql/item_timefunc.h:
  Removed 'value' from the Item_extract class definition.
sql/sql_load.cc:
  - we may need to deallocate 'buffer' even when 'error' is
    non-zero in some cases, since 'error' is public, and there is
    external code modifying it.
  - assign NULL to buffer when deallocating it so that we don't
    do it twice in the destructor
  - there is no point in changing 'error' in the destructor.

3 files changed, 7 insertions, 10 deletions

diff --git a/sql/item_timefunc.cc b/sql/item_timefunc.cc
index dff4d20f347..103bd96efd4 100644
--- a/sql/item_timefunc.cc
+++ b/sql/item_timefunc.cc
@@ -2270,8 +2270,6 @@ void Item_extract::print(String *str, enum_query_type query_type)
 
 void Item_extract::fix_length_and_dec()
 {
-  value.alloc(32);				// alloc buffer
-
   maybe_null=1;					// If wrong date
   switch (int_type) {
   case INTERVAL_YEAR:		max_length=4; date_value=1; break;
@@ -2314,6 +2312,8 @@ longlong Item_extract::val_int()
   }
   else
   {
+    char buf[40];
+    String value(buf, sizeof(buf), &my_charset_bin);;
     String *res= args[0]->val_str(&value);
     if (!res || str_to_time_with_warn(res->ptr(), res->length(), &ltime))
     {
diff --git a/sql/item_timefunc.h b/sql/item_timefunc.h
index 11eed70f399..ef86406e1be 100644
--- a/sql/item_timefunc.h
+++ b/sql/item_timefunc.h
@@ -702,7 +702,6 @@ public:
 
 class Item_extract :public Item_int_func
 {
-  String value;
   bool date_value;
  public:
   const interval_type int_type; // keep it public
diff --git a/sql/sql_load.cc b/sql/sql_load.cc
index f9386206dce..4b68f2a3821 100644
--- a/sql/sql_load.cc
+++ b/sql/sql_load.cc
@@ -1116,6 +1116,7 @@ READ_INFO::READ_INFO(File file_par, uint tot_length, CHARSET_INFO *cs,
 		      MYF(MY_WME)))
     {
       my_free((uchar*) buffer,MYF(0)); /* purecov: inspected */
+      buffer= NULL;
       error=1;
     }
     else
@@ -1142,13 +1143,10 @@ READ_INFO::READ_INFO(File file_par, uint tot_length, CHARSET_INFO *cs,
 
 READ_INFO::~READ_INFO()
 {
-  if (!error)
-  {
-    if (need_end_io_cache)
-      ::end_io_cache(&cache);
-    my_free((uchar*) buffer,MYF(0));
-    error=1;
-  }
+  if (!error && need_end_io_cache)
+    ::end_io_cache(&cache);
+
+  my_free(buffer, MYF(MY_ALLOW_ZERO_PTR));
 }