Fixed bug #27229: crash when a set function aggregated in outer

context was used as an argument of GROUP_CONCAT.
Ensured correct setting of the depended_from field in references
generated for set functions aggregated in outer selects.
A wrong value of this field resulted in wrong maps returned by 
used_tables() for these references.
Made sure that a temporary table field is added for any set function
aggregated in outer context when creation of a temporary table is 
needed to execute the inner subquery.

mysql-test/r/subselect.result

@@ -3905,3 +3905,22 @@ COUNT(*)	a
 2	2
 3	3
 DROP TABLE t1,t2;
+CREATE TABLE t1 (a int, b int);
+CREATE TABLE t2 (m int, n int);
+INSERT INTO t1 VALUES (2,2), (2,2), (3,3), (3,3), (3,3), (4,4);
+INSERT INTO t2 VALUES (1,11), (2,22), (3,32), (4,44), (4,44);
+SELECT COUNT(*) c, a,
+(SELECT GROUP_CONCAT(COUNT(a)) FROM t2 WHERE m = a)
+FROM t1 GROUP BY a;
+c	a	(SELECT GROUP_CONCAT(COUNT(a)) FROM t2 WHERE m = a)
+2	2	2
+3	3	3
+1	4	1,1
+SELECT COUNT(*) c, a,
+(SELECT GROUP_CONCAT(COUNT(a)+1) FROM t2 WHERE m = a)
+FROM t1 GROUP BY a;
+c	a	(SELECT GROUP_CONCAT(COUNT(a)+1) FROM t2 WHERE m = a)
+2	2	3
+3	3	4
+1	4	2,2
+DROP table t1,t2;

mysql-test/t/subselect.test

@@ -2763,3 +2763,22 @@ SELECT COUNT(*), a
     HAVING (SELECT MIN(m) FROM t2 WHERE m = count(*)) > 1;
 
 DROP TABLE t1,t2;
+
+#
+# Bug #27229: GROUP_CONCAT in subselect with COUNT() as an argument 
+#  
+
+CREATE TABLE t1 (a int, b int);
+CREATE TABLE t2 (m int, n int);
+INSERT INTO t1 VALUES (2,2), (2,2), (3,3), (3,3), (3,3), (4,4);
+INSERT INTO t2 VALUES (1,11), (2,22), (3,32), (4,44), (4,44);
+
+SELECT COUNT(*) c, a,
+       (SELECT GROUP_CONCAT(COUNT(a)) FROM t2 WHERE m = a)
+  FROM t1 GROUP BY a;
+
+SELECT COUNT(*) c, a,
+       (SELECT GROUP_CONCAT(COUNT(a)+1) FROM t2 WHERE m = a)
+  FROM t1 GROUP BY a;
+
+DROP table t1,t2;

sql/item.cc

@@ -1261,15 +1261,18 @@ void Item::split_sum_func2(THD *thd, Item **ref_pointer_array,
       Exception is Item_direct_view_ref which we need to convert to
       Item_ref to allow fields from view being stored in tmp table.
     */
+    Item_aggregate_ref *item_ref;
     uint el= fields.elements;
-    Item *new_item, *real_itm= real_item();
+    Item *real_itm= real_item();
 
     ref_pointer_array[el]= real_itm;
-    if (!(new_item= new Item_aggregate_ref(&thd->lex->current_select->context,
+    if (!(item_ref= new Item_aggregate_ref(&thd->lex->current_select->context,
                                            ref_pointer_array + el, 0, name)))
       return;                                   // fatal_error is set
+    if (type() == SUM_FUNC_ITEM)
+      item_ref->depended_from= ((Item_sum *) this)->depended_from(); 
     fields.push_front(real_itm);
-    thd->change_item_tree(ref, new_item);
+    thd->change_item_tree(ref, item_ref);
   }
 }
 

sql/item_sum.cc

@@ -61,9 +61,9 @@ bool Item_sum::init_sum_func_check(THD *thd)
   /* Save a pointer to object to be used in items for nested set functions */
   thd->lex->in_sum_func= this;
   nest_level= thd->lex->current_select->nest_level;
-  nest_level_tables_count= thd->lex->current_select->join->tables;
   ref_by= 0;
   aggr_level= -1;
+  aggr_sel= NULL;
   max_arg_level= -1;
   max_sum_func_level= -1;
   return FALSE;
@@ -151,7 +151,10 @@ bool Item_sum::check_sum_func(THD *thd, Item **ref)
     invalid= aggr_level < 0 && !(allow_sum_func & (1 << nest_level));
   }
   if (!invalid && aggr_level < 0)
+  {
     aggr_level= nest_level;
+    aggr_sel= thd->lex->current_select;
+  }
   /*
     By this moment we either found a subquery where the set function is
     to be aggregated  and assigned a value that is  >= 0 to aggr_level,
@@ -212,7 +215,6 @@ bool Item_sum::check_sum_func(THD *thd, Item **ref)
 bool Item_sum::register_sum_func(THD *thd, Item **ref)
 {
   SELECT_LEX *sl;
-  SELECT_LEX *aggr_sl= NULL;
   nesting_map allow_sum_func= thd->lex->allow_sum_func;
   for (sl= thd->lex->current_select->master_unit()->outer_select() ;
        sl && sl->nest_level > max_arg_level;
@@ -222,7 +224,7 @@ bool Item_sum::register_sum_func(THD *thd, Item **ref)
     {
       /* Found the most nested subquery where the function can be aggregated */
       aggr_level= sl->nest_level;
-      aggr_sl= sl;
+      aggr_sel= sl;
     }
   }
   if (sl && (allow_sum_func & (1 << sl->nest_level)))
@@ -233,21 +235,22 @@ bool Item_sum::register_sum_func(THD *thd, Item **ref)
       The set function will be aggregated in this subquery.
     */   
     aggr_level= sl->nest_level;
-    aggr_sl= sl;
+    aggr_sel= sl;
+
   }
   if (aggr_level >= 0)
   {
     ref_by= ref;
-    /* Add the object to the list of registered objects assigned to aggr_sl */
-    if (!aggr_sl->inner_sum_func_list)
+    /* Add the object to the list of registered objects assigned to aggr_sel */
+    if (!aggr_sel->inner_sum_func_list)
       next= this;
     else
     {
-      next= aggr_sl->inner_sum_func_list->next;
-      aggr_sl->inner_sum_func_list->next= this;
+      next= aggr_sel->inner_sum_func_list->next;
+      aggr_sel->inner_sum_func_list->next= this;
     }
-    aggr_sl->inner_sum_func_list= this;
-    aggr_sl->with_sum_func= 1;
+    aggr_sel->inner_sum_func_list= this;
+    aggr_sel->with_sum_func= 1;
 
     /* 
       Mark Item_subselect(s) as containing aggregate function all the way up
@@ -265,11 +268,11 @@ bool Item_sum::register_sum_func(THD *thd, Item **ref)
       has aggregate functions directly referenced (i.e. not through a sub-select).
     */
     for (sl= thd->lex->current_select; 
-         sl && sl != aggr_sl && sl->master_unit()->item;
+         sl && sl != aggr_sel && sl->master_unit()->item;
          sl= sl->master_unit()->outer_select() )
       sl->master_unit()->item->with_sum_func= 1;
   }
-  thd->lex->current_select->mark_as_dependent(aggr_sl);
+  thd->lex->current_select->mark_as_dependent(aggr_sel);
   return FALSE;
 }
 
@@ -299,10 +302,10 @@ Item_sum::Item_sum(List<Item> &list) :arg_count(list.elements),
 
 Item_sum::Item_sum(THD *thd, Item_sum *item):
   Item_result_field(thd, item), arg_count(item->arg_count),
+  aggr_sel(item->aggr_sel),
   nest_level(item->nest_level), aggr_level(item->aggr_level),
   quick_group(item->quick_group), used_tables_cache(item->used_tables_cache),
-  forced_const(item->forced_const), 
-  nest_level_tables_count(item->nest_level_tables_count)
+  forced_const(item->forced_const) 
 {
   if (arg_count <= 2)
     args=tmp_args;
@@ -447,7 +450,7 @@ void Item_sum::update_used_tables ()
 
     /* the aggregate function is aggregated into its local context */
     if (aggr_level == nest_level)
-      used_tables_cache |=  (1 << nest_level_tables_count) - 1;
+      used_tables_cache |=  (1 << aggr_sel->join->tables) - 1;
   }
 }
 

sql/item_sum.h

@@ -233,6 +233,7 @@ public:
   Item_sum *next; /* next in the circular chain of registered objects  */
   uint arg_count;
   Item_sum *in_sum_func;  /* embedding set function if any */ 
+  st_select_lex * aggr_sel; /* select where the function is aggregated       */ 
   int8 nest_level;        /* number of the nesting level of the set function */
   int8 aggr_level;        /* nesting level of the aggregating subquery       */
   int8 max_arg_level;     /* max level of unbound column references          */
@@ -242,7 +243,6 @@ public:
 protected:  
   table_map used_tables_cache;
   bool forced_const;
-  byte nest_level_tables_count;
 
 public:  
 
@@ -365,6 +365,8 @@ public:
   bool init_sum_func_check(THD *thd);
   bool check_sum_func(THD *thd, Item **ref);
   bool register_sum_func(THD *thd, Item **ref);
+  st_select_lex *depended_from() 
+    { return (nest_level == aggr_level ? 0 : aggr_sel); }
 };
 
 

sql/sql_base.cc

@@ -4864,7 +4864,6 @@ bool setup_tables_and_check_access(THD *thd,
   TABLE_LIST *leaves_tmp = NULL;
   bool first_table= true;
 
-  thd->leaf_count= 0;
   if (setup_tables (thd, context, from_clause, tables, conds, 
                     &leaves_tmp, select_insert))
     return TRUE;
@@ -4882,7 +4881,6 @@ bool setup_tables_and_check_access(THD *thd,
       return TRUE;
     }
     first_table= false;
-    thd->leaf_count++;
   }
   return FALSE;
 }

sql/sql_class.h

@@ -1492,9 +1492,6 @@ public:
     query_id_t first_query_id;
   } binlog_evt_union;
 
-  /* pass up the count of "leaf" tables in a JOIN out of setup_tables() */
-  byte leaf_count;
-
   THD();
   ~THD();
 

sql/sql_insert.cc

@@ -2349,14 +2349,12 @@ bool mysql_insert_select_prepare(THD *thd)
   DBUG_ASSERT(select_lex->leaf_tables != 0);
   lex->leaf_tables_insert= select_lex->leaf_tables;
   /* skip all leaf tables belonged to view where we are insert */
-  for (first_select_leaf_table= select_lex->leaf_tables->next_leaf,
-       thd->leaf_count --;
+  for (first_select_leaf_table= select_lex->leaf_tables->next_leaf;
        first_select_leaf_table &&
        first_select_leaf_table->belong_to_view &&
        first_select_leaf_table->belong_to_view ==
        lex->leaf_tables_insert->belong_to_view;
-       first_select_leaf_table= first_select_leaf_table->next_leaf,
-       thd->leaf_count --)
+       first_select_leaf_table= first_select_leaf_table->next_leaf)
   {}
   select_lex->leaf_tables= first_select_leaf_table;
   DBUG_RETURN(FALSE);

sql/sql_select.cc

@@ -412,7 +412,12 @@ JOIN::prepare(Item ***rref_pointer_array,
                                     &select_lex->leaf_tables, FALSE, 
                                     SELECT_ACL, SELECT_ACL))
       DBUG_RETURN(-1);
-  tables= thd->leaf_count;
+ 
+  TABLE_LIST *table_ptr;
+  for (table_ptr= select_lex->leaf_tables;
+       table_ptr;
+       table_ptr= table_ptr->next_leaf)
+    tables++;
 
   if (setup_wild(thd, tables_list, fields_list, &all_fields, wild_num) ||
       select_lex->setup_ref_array(thd, og_num) ||
@@ -9186,7 +9191,9 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
     Item::Type type=item->type();
     if (not_all_columns)
     {
-      if (item->with_sum_func && type != Item::SUM_FUNC_ITEM)
+      if (item->with_sum_func && type != Item::SUM_FUNC_ITEM &&
+          (type == Item::SUBSELECT_ITEM ||
+           (item->used_tables() & ~PSEUDO_TABLE_BITS)))
       {
 	/*
 	  Mark that the we have ignored an item that refers to a summary