cyclic reference test removed, becouse testing of Item::fixed field apply more strict limitation

mysql-test/r/subselect.result:
  test of cyclic reference false alarm
mysql-test/t/subselect.test:
  test of cyclic reference false alarm

mysql-test/r/subselect.result

@@ -122,6 +122,9 @@ SELECT (SELECT 1.5,'c','a') = ROW(1.5,2,'a');
 0
 SELECT (SELECT * FROM (SELECT 'test' a,'test' b) a);
 Cardinality error (more/less than 1 columns)
+SELECT 1 as a,(SELECT a+a) b,(SELECT b);
+a	b	(SELECT b)
+1	2	2
 create table t1 (a int);
 create table t2 (a int, b int);
 create table t3 (a int);

mysql-test/t/subselect.test

@@ -54,6 +54,8 @@ SELECT (SELECT 1.5,'c','a') = ROW(1.5,2,'a');
 -- error 1239
 SELECT (SELECT * FROM (SELECT 'test' a,'test' b) a);
 
+SELECT 1 as a,(SELECT a+a) b,(SELECT b);
+
 create table t1 (a int);
 create table t2 (a int, b int);
 create table t3 (a int);

sql/item.cc

@@ -71,19 +71,6 @@ Item_ident::Item_ident(Item_ident &item):
   depended_from(item.depended_from)
 {}
 
-bool Item::check_loop(uint id)
-{
-  DBUG_ENTER("Item::check_loop");
-  DBUG_PRINT("info", ("id %u, name %s", id, name));
-  if (loop_id == id)
-  {
-    DBUG_PRINT("info", ("id match"));
-    DBUG_RETURN(1);
-  }
-  loop_id= id;
-  DBUG_RETURN(0);
-}
-
 bool Item::check_cols(uint c)
 {
   if (c != 1)
@@ -680,7 +667,6 @@ bool Item_field::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
 	  return 1;
 	r->depended_from= last;
 	cursel->mark_as_dependent(last);
-	thd->add_possible_loop(r);
 	return 0;
       }
       else
@@ -1170,7 +1156,6 @@ bool Item_ref::fix_fields(THD *thd,TABLE_LIST *tables, Item **reference)
 	}
 	ref= (depended_from= last)->ref_pointer_array + counter-1;
 	thd->lex.current_select->mark_as_dependent(last);
-	thd->add_possible_loop(this);
       }
     }
     else if (!ref)
@@ -1208,14 +1193,6 @@ bool Item_ref::fix_fields(THD *thd,TABLE_LIST *tables, Item **reference)
   return 0;
 }
 
-bool Item_ref::check_loop(uint id)
-{
-  DBUG_ENTER("Item_ref::check_loop");
-  if (Item_ident::check_loop(id))
-    DBUG_RETURN(1);
-  DBUG_RETURN((*ref)->check_loop(id));
-}
-
 bool Item_default_value::eq(const Item *item, bool binary_cmp) const
 {
   return item->type() == DEFAULT_VALUE_ITEM && 

sql/item.h

@@ -92,7 +92,6 @@ public:
   virtual bool get_date(TIME *ltime,bool fuzzydate);
   virtual bool get_time(TIME *ltime);
   virtual bool is_null() { return 0; };
-  virtual bool check_loop(uint id);
   virtual void top_level_item() {}
   virtual Item * get_same() { return this; }
   virtual Item * get_tmp_table_item() { return get_same(); }
@@ -500,7 +499,6 @@ public:
   enum Item_result result_type () const { return (*ref)->result_type(); }
   enum_field_types field_type() const   { return (*ref)->field_type(); }
   table_map used_tables() const		{ return (*ref)->used_tables(); }
-  bool check_loop(uint id);
 };
 
 class Item_in_subselect;
@@ -689,10 +687,6 @@ public:
   enum Type type() const { return DEFAULT_VALUE_ITEM; }
   bool eq(const Item *item, bool binary_cmp) const;
   bool fix_fields(THD *, struct st_table_list *, Item **);
-  bool check_loop(uint id)
-  {
-    return Item_field::check_loop(id) || arg->check_loop(id);
-  }
   void set_outer_resolving() { arg->set_outer_resolving(); }
   void print(String *str);
   virtual bool basic_const_item() const { return true; }

sql/item_cmpfunc.cc

@@ -925,16 +925,6 @@ void Item_func_case::set_outer_resolving()
   Item_func::set_outer_resolving();
 }
 
-bool Item_func_case::check_loop(uint id)
-{
-  DBUG_ENTER("Item_func_case::check_loop");
-  if (Item_func::check_loop(id))
-    DBUG_RETURN(1);
-
-  DBUG_RETURN((first_expr && first_expr->check_loop(id)) ||
-	      (else_expr && else_expr->check_loop(id)));
-}
-
 void Item_func_case::update_used_tables()
 {
   Item_func::update_used_tables();
@@ -1486,21 +1476,6 @@ Item_cond::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
   return 0;
 }
 
-bool Item_cond::check_loop(uint id)
-{
-  DBUG_ENTER("Item_cond::check_loop");
-  if (Item_func::check_loop(id))
-    DBUG_RETURN(1);
-  List_iterator<Item> li(list);
-  Item *item;
-  while ((item= li++))
-  {
-    if (item->check_loop(id))
-      DBUG_RETURN(1);
-  }
-  DBUG_RETURN(0);
-}
-
 void Item_cond::set_outer_resolving()
 {
   Item_func::set_outer_resolving();

sql/item_cmpfunc.h

@@ -354,7 +354,6 @@ public:
   void print(String *str);
   bool fix_fields(THD *thd, struct st_table_list *tlist, Item **ref);
   Item *find_item(String *str);
-  bool check_loop(uint id);
   void set_outer_resolving();
 };
 
@@ -637,13 +636,6 @@ class Item_func_in :public Item_int_func
   const char *func_name() const { return " IN "; }
   void update_used_tables();
   void split_sum_func(Item **ref_pointer_array, List<Item> &fields);
-  bool check_loop(uint id)
-  {
-    DBUG_ENTER("Item_func_in::check_loop");
-    if (Item_func::check_loop(id))
-      DBUG_RETURN(1);
-    DBUG_RETURN(item->check_loop(id));
-  }
   bool nulls_in_row();
   void set_outer_resolving()
   {
@@ -789,7 +781,6 @@ public:
   void print(String *str);
   void split_sum_func(Item **ref_pointer_array, List<Item> &fields);
   friend int setup_conds(THD *thd,TABLE_LIST *tables,COND **conds);
-  bool check_loop(uint id);
   void top_level_item() { abort_on_null=1; }
   void set_outer_resolving();
 };

sql/item_func.cc

@@ -128,23 +128,6 @@ Item_func::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
   return 0;
 }
 
-bool Item_func::check_loop(uint id)
-{
-  DBUG_ENTER("Item_func::check_loop");
-  if (Item_result_field::check_loop(id))
-    DBUG_RETURN(1);
-  if (arg_count)
-  {
-    Item **arg,**arg_end;
-    for (arg= args, arg_end= args+arg_count; arg != arg_end; arg++)
-    {
-      if ((*arg)->check_loop(id))
-	DBUG_RETURN(1);
-    }
-  }
-  DBUG_RETURN(0);
-}
-
 void Item_func::set_outer_resolving()
 {
   if (arg_count)
@@ -2365,20 +2348,6 @@ bool Item_func_match::fix_fields(THD *thd, TABLE_LIST *tlist, Item **ref)
   return 0;
 }
 
-bool Item_func_match::check_loop(uint id)
-{
-  DBUG_ENTER("Item_func_match::check_loop");
-  if (Item_real_func::check_loop(id))
-    DBUG_RETURN(1);
-
-  List_iterator<Item> li(fields);
-  Item *item;
-  while ((item= li++))
-    if (item->check_loop(id))
-      DBUG_RETURN(1);
-  DBUG_RETURN(0);
-}
-
 void Item_func_match::set_outer_resolving()
 {
   Item_real_func::set_outer_resolving();

sql/item_func.h

@@ -133,7 +133,6 @@ public:
   friend class udf_handler;
   Field *tmp_table_field() { return result_field; }
   Field *tmp_table_field(TABLE *t_arg);
-  bool check_loop(uint id);
   void set_outer_resolving();
   Item * get_tmp_table_item();
 };
@@ -627,13 +626,6 @@ public:
     const_item_cache&=  item->const_item();
     with_sum_func= with_sum_func || item->with_sum_func;
   }
-  bool check_loop(uint id)
-  {
-    DBUG_ENTER("Item_func_field::check_loop");
-    if (Item_int_func::check_loop(id))
-      DBUG_RETURN(1);
-    DBUG_RETURN(item->check_loop(id));
-  }
   void set_outer_resolving()
   {
     item->set_outer_resolving();
@@ -1013,7 +1005,6 @@ public:
 
   bool fix_index();
   void init_search(bool no_order);
-  bool check_loop(uint id);
   void set_outer_resolving();
 };
 

sql/item_row.cc

@@ -120,13 +120,3 @@ void Item_row::set_outer_resolving()
   for (uint i= 0; i < arg_count; i++)
     items[i]->set_outer_resolving();
 }
-
-bool Item_row::check_loop(uint id)
-{
-  if (Item::check_loop(id))
-    return 1;
-  for (uint i= 0; i < arg_count; i++)
-    if (items[i]->check_loop(id))
-      return 1;
-  return 0;
-}

sql/item_row.h

@@ -68,7 +68,6 @@ public:
   bool const_item() const { return const_item_cache; };
   enum Item_result result_type() const { return ROW_RESULT; }
   void update_used_tables();
-  bool check_loop(uint id);
   void set_outer_resolving();
 
   uint cols() { return arg_count; }

sql/item_strfunc.h

@@ -106,13 +106,6 @@ public:
 	    Item_func::fix_fields(thd, tlist, ref));
   }
   const char *func_name() const { return "concat_ws"; }
-  bool check_loop(uint id)
-  {
-    DBUG_ENTER("Item_func_concat_ws::check_loop");
-    if (Item_str_func::check_loop(id))
-      DBUG_RETURN(1);
-    DBUG_RETURN(separator->check_loop(id));
-  }
   void set_outer_resolving()
   {
     separator->set_outer_resolving();
@@ -389,13 +382,6 @@ public:
   void fix_length_and_dec();
   void update_used_tables();
   const char *func_name() const { return "elt"; }
-  bool check_loop(uint id)
-  {
-    DBUG_ENTER("Item_func_elt::check_loop");
-    if (Item_str_func::check_loop(id))
-      DBUG_RETURN(1);
-    DBUG_RETURN(item->check_loop(id));
-  }
   void set_outer_resolving()
   {
     item->set_outer_resolving();
@@ -422,13 +408,6 @@ public:
   void fix_length_and_dec();
   void update_used_tables();
   const char *func_name() const { return "make_set"; }
-  bool check_loop(uint id)
-  {
-    DBUG_ENTER("Item_func_make_set::check_loop");
-    if (Item_str_func::check_loop(id))
-      DBUG_RETURN(1);
-    DBUG_RETURN(item->check_loop(id));
-  }
   void set_outer_resolving()
   {
     item->set_outer_resolving();

sql/item_subselect.cc

@@ -108,15 +108,6 @@ bool Item_subselect::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
   return res;
 }
 
-bool Item_subselect::check_loop(uint id)
-{
-  DBUG_ENTER("Item_subselect::check_loop");
-  if (Item_result_field::check_loop(id))
-    DBUG_RETURN(1);
-  
-  DBUG_RETURN(engine->check_loop(id));
-}
-
 Item::Type Item_subselect::type() const 
 {
   return SUBSELECT_ITEM;
@@ -858,21 +849,6 @@ bool subselect_union_engine::uncacheable()
   return unit->uncacheable;
 }
 
-bool subselect_single_select_engine::check_loop(uint id)
-{
-  DBUG_ENTER("subselect_single_select_engine::check_loop");
-  DBUG_RETURN(join->check_loop(id));
-}
-
-bool subselect_union_engine::check_loop(uint id)
-{
-  DBUG_ENTER("subselect_union_engine::check_loop");
-  for (SELECT_LEX *sl= unit->first_select(); sl; sl= sl->next_select())
-    if (sl->join && sl->join->check_loop(id))
-      DBUG_RETURN(1);
-  DBUG_RETURN(0);
-}
-
 void subselect_single_select_engine::exclude()
 {
   select_lex->master_unit()->exclude_level();

sql/item_subselect.h

@@ -83,7 +83,6 @@ public:
   bool fix_fields(THD *thd, TABLE_LIST *tables, Item **ref);
   virtual void fix_length_and_dec();
   table_map used_tables() const;
-  bool check_loop(uint id);
 
   friend class select_subselect;
   friend class Item_in_optimizer;
@@ -226,7 +225,6 @@ public:
   virtual bool dependent()= 0; /* depended from outer select */
   virtual bool uncacheable()= 0; /* query is uncacheable */
   enum Item_result type() { return res_type; }
-  virtual bool check_loop(uint id)= 0;
   virtual void exclude()= 0;
   bool may_be_null() { return maybe_null; };
 };
@@ -248,7 +246,6 @@ public:
   uint cols();
   bool dependent();
   bool uncacheable();
-  bool check_loop(uint id);
   void exclude();
 };
 
@@ -266,6 +263,5 @@ public:
   uint cols();
   bool dependent();
   bool uncacheable();
-  bool check_loop(uint id);
   void exclude();
 };

sql/sql_class.cc

@@ -479,14 +479,6 @@ void THD::close_active_vio()
 }
 #endif
 
-void THD::add_possible_loop (Item *item)
-{
-  if (!possible_loops)
-  {
-    possible_loops= new List<Item>;
-  }
-  possible_loops->push_back(item);
-}
 
 /*****************************************************************************
 ** Functions to provide a interface to select results

sql/sql_class.h

@@ -506,7 +506,6 @@ public:
   table_map  used_tables;
   USER_CONN *user_connect;
   CHARSET_INFO *db_charset;   
-  List<Item> *possible_loops; // Items that may cause loops in subselects
   List<TABLE> temporary_tables_should_be_free; // list of temporary tables
   List	     <MYSQL_ERROR> warn_list;  
   uint	     warn_count[(uint) MYSQL_ERROR::WARN_LEVEL_END];
@@ -521,7 +520,6 @@ public:
   uint32     query_length;
   uint32     db_length;
   uint       select_number;             //number of select (used for EXPLAIN)
-  uint       check_loops_counter;       //last id used to check loops
   /* variables.transaction_isolation is reset to this after each commit */
   enum_tx_isolation session_tx_isolation;
              // extend scramble to handle new auth
@@ -661,8 +659,6 @@ public:
 #else
   void clear_error();
 #endif
-
-  void add_possible_loop(Item *);
 };
 
 /*

sql/sql_parse.cc

@@ -3146,18 +3146,16 @@ mysql_init_query(THD *thd)
   lex->select_lex.prev= &lex->unit.slave;
   lex->select_lex.link_next= lex->select_lex.slave= lex->select_lex.next= 0;
   lex->select_lex.link_prev= (st_select_lex_node**)&(lex->all_selects_list);
-  lex->olap=lex->describe=0;
+  lex->olap=lex->describe= 0;
   lex->derived_tables= false;
-  lex->lock_option=TL_READ;
-  lex->found_colon=0;
-  thd->check_loops_counter= thd->select_number=
-    lex->select_lex.select_number= 1;
+  lex->lock_option= TL_READ;
+  lex->found_colon= 0;
+  thd->select_number= lex->select_lex.select_number= 1;
   thd->free_list= 0;
   thd->total_warn_count=0;			// Warnings for this query
   thd->last_insert_id_used= thd->query_start_used= thd->insert_id_used=0;
   thd->sent_row_count= thd->examined_row_count= 0;
   thd->fatal_error= thd->rand_used= 0;
-  thd->possible_loops= 0;
   thd->server_status &= ~SERVER_MORE_RESULTS_EXISTS;
   DBUG_VOID_RETURN;
 }

sql/sql_select.cc

@@ -1274,24 +1274,6 @@ JOIN::cleanup(THD *thd)
   DBUG_RETURN(error);
 }
 
-bool JOIN::check_loop(uint id)
-{
-  DBUG_ENTER("JOIN::check_loop");
-  Item *item;
-  List_iterator<Item> it(all_fields);
-  DBUG_PRINT("info", ("all_fields:"));
-  while ((item= it++))
-    if (item->check_loop(id))
-      DBUG_RETURN(1);
-  DBUG_PRINT("info", ("where:"));
-  if (select_lex->where && select_lex->where->check_loop(id))
-    DBUG_RETURN(1);
-  DBUG_PRINT("info", ("having:"));
-  if (select_lex->having && select_lex->having->check_loop(id))
-    DBUG_RETURN(1);
-  DBUG_RETURN(0);
-}
-
 int
 mysql_select(THD *thd, Item ***rref_pointer_array,
 	     TABLE_LIST *tables, uint wild_num, List<Item> &fields, 
@@ -1329,23 +1311,6 @@ mysql_select(THD *thd, Item ***rref_pointer_array,
     {
       DBUG_RETURN(-1);
     }
-    if (thd->possible_loops)
-    {
-      Item *item;
-      while (thd->possible_loops->elements)
-      {
-	item= thd->possible_loops->pop();
-    	if (item->check_loop(thd->check_loops_counter++))
-	{
-	  delete thd->possible_loops;
-	  thd->possible_loops= 0;
-	  my_message(ER_CYCLIC_REFERENCE, ER(ER_CYCLIC_REFERENCE), MYF(0));
-	  return 1;
-	}
-      }
-      delete thd->possible_loops;
-      thd->possible_loops= 0;
-    }
   }
 
   if ((err= join->optimize()))

sql/sql_select.h

@@ -261,7 +261,6 @@ class JOIN :public Sql_alloc
   int reinit();
   void exec();
   int cleanup(THD *thd);
-  bool check_loop(uint id);
   void restore_tmp();
 
   inline void init_items_ref_array()