postreview fix

sql/item_cmpfunc.cc:
  comment fixed
sql/item_subselect.cc:
  comment fixed
  debug info and inherited method call
sql/item_subselect.h:
  comment fixed
sql/item_sum.cc:
  comment fixed
sql/item_sum.h:
  comment fixed

sql/item_cmpfunc.cc

@@ -146,7 +146,9 @@ void Item_func_not_all::print(String *str)
 
 
 /*
-  special NOP for ALL subquery
+  Special NOP (No OPeration) for ALL subquery it is like  Item_func_not_all
+  (return TRUE if underlaying sudquery do not return rows) but if subquery
+  returns some rows it return same value as argument (TRUE/FALSE).
 */
 
 longlong Item_func_nop_all::val_int()

sql/item_subselect.cc

@@ -292,14 +292,19 @@ Item_maxmin_subselect::Item_maxmin_subselect(Item_subselect *parent,
 
 void Item_maxmin_subselect::cleanup()
 {
+  DBUG_ENTER("Item_maxmin_subselect::cleanup");
+  Item_singlerow_subselect::cleanup();
+
   /*
-    By default is is TRUE to avoid TRUE reporting by
+    By default it is TRUE to avoid TRUE reporting by
     Item_func_not_all/Item_func_nop_all if this item was never called.
 
     Engine exec() set it to FALSE by reset_value_registration() call.
+    select_max_min_finder_subselect::send_data() set it back to TRUE if some
+    value will be found.
   */
-
   was_values= TRUE;
+  DBUG_VOID_RETURN;
 }
 
 

sql/item_subselect.h

@@ -160,7 +160,7 @@ class Item_maxmin_subselect :public Item_singlerow_subselect
 {
 protected:
   bool max;
-  bool was_values;  // was checked at least some values
+  bool was_values;  // Set if we have found at least one row
 public:
   Item_maxmin_subselect(Item_subselect *parent,
 			st_select_lex *select_lex, bool max);

sql/item_sum.cc

@@ -537,11 +537,13 @@ void Item_sum_hybrid::cleanup()
   DBUG_ENTER("Item_sum_hybrid::cleanup");
   Item_sum::cleanup();
   used_table_cache= ~(table_map) 0;
+
   /*
-    by default is is TRUE to avoid TRUE reporting by
+    by default it is TRUE to avoid TRUE reporting by
     Item_func_not_all/Item_func_nop_all if this item was never called.
 
     no_rows_in_result() set it to FALSE if was not results found.
+    If some results found it will be left unchanged.
   */
   was_values= TRUE;
   DBUG_VOID_RETURN;

sql/item_sum.h

@@ -402,7 +402,7 @@ class Item_sum_hybrid :public Item_sum
   enum_field_types hybrid_field_type;
   int cmp_sign;
   table_map used_table_cache;
-  bool was_values;  // was checked at least some values (for max/min only)
+  bool was_values;  // Set if we have found at least one row (for max/min only)
 
   public:
   Item_sum_hybrid(Item *item_par,int sign)