Bug#48060 Memory leak - Item::val_bool() (item.cc:184) from optimizer_subquery grammar

Item_sum::set_aggregator() may be called multiple times during query preparation.
On subsequent calls: verify that the aggregator type is the same,
and re-use the existing Aggregator.


sql/item_sum.cc:
  In Item_sum::set_aggregator(): re-use existing Aggregator if already set.
  
  Remove some friend declarations, add some accessor functions.
  Cleanup some DBUG_ENTER and DBUG_RETURN code.
sql/item_sum.h:
  Make some member fields private, add accessors instead.
  Remove some un-necessary friend declarations.
  Remove some default arguments from constructors.
sql/opt_sum.cc:
  Use accessor functions in Item_sum.
sql/sql_select.cc:
  Fix mis-spelled DBUG_ENTER text.
  Use accessor functions in Item_sum.
sql/sql_yacc.yy:
  Use explicit true/false rather than default arguments when constructing
  Item_sum_xxx objects.

1 files changed, 23 insertions, 20 deletions

diff --git a/sql/item_sum.h b/sql/item_sum.h
index 62addf4e033..6d7418204fc 100644
--- a/sql/item_sum.h
+++ b/sql/item_sum.h
@@ -302,13 +302,14 @@ class st_select_lex;
 
 class Item_sum :public Item_result_field
 {
-public:
+protected:
   /**
     Aggregator class instance. Not set initially. Allocated only after
     it is determined if the incoming data are already distinct.
   */
   Aggregator *aggr;
 
+private:
   /**
     Used in making ROLLUP. Set for the ROLLUP copies of the original
     Item_sum and passed to create_tmp_field() to cause it to work
@@ -324,6 +325,11 @@ public:
   */
   bool with_distinct;
 
+public:
+
+  bool has_force_copy_fields() const { return force_copy_fields; }
+  bool has_with_distinct()     const { return with_distinct; }
+
   enum Sumfunctype
   { COUNT_FUNC, COUNT_DISTINCT_FUNC, SUM_FUNC, SUM_DISTINCT_FUNC, AVG_FUNC,
     AVG_DISTINCT_FUNC, MIN_FUNC, MAX_FUNC, STD_FUNC,
@@ -447,12 +453,12 @@ public:
     may be initialized to 0 by clear() and to NULL by
     no_rows_in_result().
   */
-  void no_rows_in_result()
+  virtual void no_rows_in_result()
   {
     if (!aggr)
-     set_aggregator(with_distinct ?
-                    Aggregator::DISTINCT_AGGREGATOR :
-                    Aggregator::SIMPLE_AGGREGATOR);
+      set_aggregator(with_distinct ?
+                     Aggregator::DISTINCT_AGGREGATOR :
+                     Aggregator::SIMPLE_AGGREGATOR);
     reset();
   }
   virtual void make_unique() { force_copy_fields= TRUE; }
@@ -511,11 +517,12 @@ public:
   */
 
   int set_aggregator(Aggregator::Aggregator_type aggregator);
+
   virtual void clear()= 0;
   virtual bool add()= 0;
-  virtual bool setup(THD *thd) {return 0;}
+  virtual bool setup(THD *thd) { return false; }
 
-  void cleanup ();
+  virtual void cleanup();
 };
 
 
@@ -533,9 +540,6 @@ class Unique;
 class Aggregator_distinct : public Aggregator
 {
   friend class Item_sum_sum;
-  friend class Item_sum_count;
-  friend class Item_sum_avg;
-protected:
 
   /* 
     flag to prevent consecutive runs of endup(). Normally in endup there are 
@@ -567,7 +571,7 @@ protected:
   uint32 *field_lengths;
 
   /*
-    used in conjunction with 'table' to support the access to Field classes 
+    Used in conjunction with 'table' to support the access to Field classes 
     for COUNT(DISTINCT). Needed by copy_fields()/copy_funcs().
   */
   TMP_TABLE_PARAM *tmp_table_param;
@@ -637,7 +641,6 @@ public:
 
 class Item_sum_num :public Item_sum
 {
-  friend class Aggregator_distinct;
 protected:
   /*
    val_xxx() functions may be called several times during the execution of a 
@@ -692,14 +695,14 @@ protected:
   void fix_length_and_dec();
 
 public:
-  Item_sum_sum(Item *item_par, bool distinct= FALSE) :Item_sum_num(item_par) 
+  Item_sum_sum(Item *item_par, bool distinct) :Item_sum_num(item_par) 
   {
     set_distinct(distinct);
   }
   Item_sum_sum(THD *thd, Item_sum_sum *item);
   enum Sumfunctype sum_func () const 
   { 
-    return with_distinct ? SUM_DISTINCT_FUNC : SUM_FUNC; 
+    return has_with_distinct() ? SUM_DISTINCT_FUNC : SUM_FUNC; 
   }
   void clear();
   bool add();
@@ -713,7 +716,7 @@ public:
   void no_rows_in_result() {}
   const char *func_name() const 
   { 
-    return with_distinct ? "sum(distinct " : "sum("; 
+    return has_with_distinct() ? "sum(distinct " : "sum("; 
   }
   Item *copy_or_same(THD* thd);
 };
@@ -752,7 +755,7 @@ class Item_sum_count :public Item_sum_int
   {}
   enum Sumfunctype sum_func () const 
   { 
-    return with_distinct ? COUNT_DISTINCT_FUNC : COUNT_FUNC; 
+    return has_with_distinct() ? COUNT_DISTINCT_FUNC : COUNT_FUNC; 
   }
   void no_rows_in_result() { count=0; }
   void make_const(longlong count_arg) 
@@ -765,7 +768,7 @@ class Item_sum_count :public Item_sum_int
   void update_field();
   const char *func_name() const 
   { 
-    return with_distinct ? "count(distinct " : "count(";
+    return has_with_distinct() ? "count(distinct " : "count(";
   }
   Item *copy_or_same(THD* thd);
 };
@@ -806,7 +809,7 @@ public:
   uint prec_increment;
   uint f_precision, f_scale, dec_bin_size;
 
-  Item_sum_avg(Item *item_par, bool distinct= FALSE) 
+  Item_sum_avg(Item *item_par, bool distinct) 
     :Item_sum_sum(item_par, distinct), count(0) 
   {}
   Item_sum_avg(THD *thd, Item_sum_avg *item)
@@ -816,7 +819,7 @@ public:
   void fix_length_and_dec();
   enum Sumfunctype sum_func () const 
   {
-    return with_distinct ? AVG_DISTINCT_FUNC : AVG_FUNC;
+    return has_with_distinct() ? AVG_DISTINCT_FUNC : AVG_FUNC;
   }
   void clear();
   bool add();
@@ -832,7 +835,7 @@ public:
   void no_rows_in_result() {}
   const char *func_name() const 
   { 
-    return with_distinct ? "avg(distinct " : "avg("; 
+    return has_with_distinct() ? "avg(distinct " : "avg("; 
   }
   Item *copy_or_same(THD* thd);
   Field *create_tmp_field(bool group, TABLE *table, uint convert_blob_length);