Fixed bug#36005: server crashes inside NOT IN clause subquery with

                 impossible WHERE/HAVING clause
                 (subselect_single_select_engine::exec).

Allocation and initialization of joined table list t1, t2... of
subqueries like:

    NOT IN (SELECT ... FROM t1,t2,... WHERE 0)

is optimized out, however server tries to traverse this list.


mysql-test/r/subselect3.result:
  Added test case for bug#36005.
mysql-test/t/subselect3.test:
  Added test case for bug#36005.
sql/sql_select.cc:
  Fixed bug#36005.
  
  1. JOIN::prepare initializes JOIN::table counter (actually a size
     of the JOIN::join_tab array) and sets it to a number of joined tables.
  
  2. The make_join_statistics function (when called from JOIN::optimize)
     allocates and fills the JOIN::join_tab array.
     However, when optimizing subselect has impossible (definite false)
     WHERE or HAVING clause, optimizer skips call to make_join_statistics
     and leaves JOIN::join_tab == NULL.
  
  3. subselect_single_select_engine::exec does traversal of the JOIN::join_tab
     array and the server dies because array is not allocated but array
     counter is greater than 0.
  
  The JOIN::optimize method has been modified to reset the JOIN::table
  counter to 0 in cause of impossible WHERE/HAVING clause.

mysql-test/r/subselect3.result

@@ -770,4 +770,13 @@ SELECT ROW(1, 2) IN (SELECT t1.a, 2 FROM t2) FROM t1 GROUP BY t1.a;
 ROW(1, 2) IN (SELECT t1.a, 2 FROM t2)
 1
 DROP TABLE t1, t2;
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2),(3);
+CREATE TABLE t2 SELECT * FROM t1;
+SELECT 1 FROM t1 WHERE t1.a NOT IN (SELECT 1 FROM t1, t2 WHERE 0);
+1
+1
+1
+1
+DROP TABLE t1, t2;
 End of 5.0 tests

mysql-test/t/subselect3.test

@@ -605,4 +605,17 @@ SELECT ROW(1, 2) IN (SELECT t1.a, 2 FROM t2) FROM t1 GROUP BY t1.a;
 
 DROP TABLE t1, t2;
 
+#
+# Bug #36005: crash in subselect with single row
+#             (subselect_single_select_engine::exec)
+#
+
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2),(3);
+CREATE TABLE t2 SELECT * FROM t1;
+
+SELECT 1 FROM t1 WHERE t1.a NOT IN (SELECT 1 FROM t1, t2 WHERE 0);
+
+DROP TABLE t1, t2;
+
 --echo End of 5.0 tests

sql/sql_select.cc

@@ -832,6 +832,7 @@ JOIN::optimize()
                             "Impossible HAVING" : "Impossible WHERE"));
       zero_result_cause=  having_value == Item::COND_FALSE ?
                            "Impossible HAVING" : "Impossible WHERE";
+      tables= 0;
       error= 0;
       DBUG_RETURN(0);
     }