Fixed bug#19077: A nested materialized derived table is used before being populated.

The convert_constant_item() function converts constant items to ints on
prepare phase to optimize execution speed. In this case it tries to evaluate
subselect which contains a derived table and is contained in a derived table. 
All derived tables are filled only after all derived tables are prepared.
So evaluation of subselect with derived table at the prepare phase will
return a wrong result.

A new flag with_subselect is added to the Item class. It indicates that
expression which this item represents is a subselect or contains a subselect.
It is set to 0 by default. It is set to 1 in the Item_subselect constructor
for subselects.
For Item_func and Item_cond derived classes it is set after fixing any argument
in Item_func::fix_fields() and Item_cond::fix_fields accordingly.
The convert_constant_item() function now doesn't convert a constant item
if the with_subselect flag set in it. 

mysql-test/r/subselect.result

@@ -3177,3 +3177,9 @@ ERROR 42S22: Unknown column 'no_such_column' in 'where clause'
 SELECT * FROM t1 WHERE no_such_column = ANY (SELECT 1);
 ERROR 42S22: Unknown column 'no_such_column' in 'IN/ALL/ANY subquery'
 DROP TABLE t1;
+create table t1 (i int, j bigint);
+insert into t1 values (1, 2), (2, 2), (3, 2);
+select * from (select min(i) from t1 where j=(select * from (select min(j) from t1) t2)) t3;
+min(i)
+1
+drop table t1;

mysql-test/r/view.result

@@ -2660,3 +2660,12 @@ SELECT * FROM v1;
 id	t	COUNT(*)
 DROP VIEW v1;
 DROP TABLE t1;
+CREATE TABLE t1 (i INT, j BIGINT);
+INSERT INTO t1 VALUES (1, 2), (2, 2), (3, 2);
+CREATE VIEW v1 AS SELECT MIN(j) AS j FROM t1;
+CREATE VIEW v2 AS SELECT MIN(i) FROM t1 WHERE j = ( SELECT * FROM v1 );
+SELECT * FROM v2;
+MIN(i)
+1
+DROP VIEW v2, v1;
+DROP TABLE t1;

mysql-test/t/subselect.test

@@ -2100,3 +2100,12 @@ CREATE VIEW v2 AS SELECT * FROM t1 WHERE no_such_column = (SELECT 1);
 SELECT * FROM t1 WHERE no_such_column = ANY (SELECT 1);
 
 DROP TABLE t1;
+
+#
+# Bug#19077: A nested materialized derived table is used before being populated.
+#
+create table t1 (i int, j bigint);
+insert into t1 values (1, 2), (2, 2), (3, 2);
+select * from (select min(i) from t1 where j=(select * from (select min(j) from t1) t2)) t3;
+drop table t1;
+

mysql-test/t/view.test

@@ -2528,3 +2528,14 @@ SELECT * FROM v1;
 
 DROP VIEW v1;
 DROP TABLE t1;
+
+#
+# Bug#19077: A nested materialized view is used before being populated.
+#
+CREATE TABLE t1 (i INT, j BIGINT);
+INSERT INTO t1 VALUES (1, 2), (2, 2), (3, 2);
+CREATE VIEW v1 AS SELECT MIN(j) AS j FROM t1;
+CREATE VIEW v2 AS SELECT MIN(i) FROM t1 WHERE j = ( SELECT * FROM v1 );
+SELECT * FROM v2;
+DROP VIEW v2, v1;
+DROP TABLE t1;

sql/item.cc

@@ -304,6 +304,7 @@ Item::Item():
   marker= 0;
   maybe_null=null_value=with_sum_func=unsigned_flag=0;
   decimals= 0; max_length= 0;
+  with_subselect= 0;
 
   /* Put item in free list so that we can free all items at end */
   THD *thd= current_thd;

sql/item.h

@@ -460,6 +460,9 @@ public:
   my_bool is_autogenerated_name;        /* indicate was name of this Item
                                            autogenerated or set by user */
   DTCollation collation;
+  my_bool with_subselect;               /* If this item is a subselect or some
+                                           of its arguments is or contains a
+                                           subselect */
 
   // alloc & destruct is done as start of select using sql_alloc
   Item();

sql/item_cmpfunc.cc

@@ -204,10 +204,28 @@ longlong Item_func_nop_all::val_int()
 
 
 /*
-  Convert a constant expression or string to an integer.
-  This is done when comparing DATE's of different formats and
-  also when comparing bigint to strings (in which case the string
-  is converted once to a bigint).
+  Convert a constant item to an int and replace the original item
+
+  SYNOPSIS
+    convert_constant_item()
+    thd             thread handle
+    field           item will be converted using the type of this field
+    item  [in/out]  reference to the item to convert
+
+  DESCRIPTION
+    The function converts a constant expression or string to an integer.
+    On successful conversion the original item is substituted for the
+    result of the item evaluation.
+    This is done when comparing DATE/TIME of different formats and
+    also when comparing bigint to strings (in which case strings
+    are converted to bigints).
+
+  NOTES
+    This function is called only at prepare stage.
+    As all derived tables are filled only after all derived tables
+    are prepared we do not evaluate items with subselects here because
+    they can contain derived tables and thus we may attempt to use a
+    table that has not been populated yet.
 
   RESULT VALUES
   0	Can't convert item
@@ -216,7 +234,7 @@ longlong Item_func_nop_all::val_int()
 
 static bool convert_constant_item(THD *thd, Field *field, Item **item)
 {
-  if ((*item)->const_item())
+  if (!(*item)->with_subselect && (*item)->const_item())
   {
     /* For comparison purposes allow invalid dates like 2000-01-32 */
     ulong orig_sql_mode= field->table->in_use->variables.sql_mode;
@@ -2578,6 +2596,7 @@ Item_cond::fix_fields(THD *thd, Item **ref)
       const_item_cache= FALSE;
     }  
     with_sum_func=	    with_sum_func || item->with_sum_func;
+    with_subselect|=        item->with_subselect;
     if (item->maybe_null)
       maybe_null=1;
   }

sql/item_func.cc

@@ -184,6 +184,7 @@ Item_func::fix_fields(THD *thd, Item **ref)
       used_tables_cache|=     item->used_tables();
       not_null_tables_cache|= item->not_null_tables();
       const_item_cache&=      item->const_item();
+      with_subselect|=        item->with_subselect;
     }
   }
   fix_length_and_dec();

sql/item_subselect.cc

@@ -39,6 +39,7 @@ Item_subselect::Item_subselect():
   engine(0), old_engine(0), used_tables_cache(0), have_to_be_excluded(0),
   const_item_cache(1), engine_changed(0), changed(0)
 {
+  with_subselect= 1;
   reset();
   /*
     item value is NULL if select_subselect not changed this value