Bug#57704 Cleanup code dies with void TABLE::set_keyread(bool): Assertion `file' failed.

This bug was introduced in this revision: 
kostja@sun.com-20100727102553-b4n2ojcyfj79l2x7
("A pre-requisite patch for the fix for Bug#52044.")

It happens because close_thread_tables() is now called in
open_and_lock_tables upon failure.  Hence, table is no longer
open when optimizer tries to do cleanup.

Fix: Make sure to do cleanup in st_select_lex_unit::prepare()
upon failure. This way, cleanup() is called before tables are
released.

mysql-test/r/subselect.result:
  Added test case for Bug#57704.
mysql-test/t/subselect.test:
  Added test case for Bug#57704.
sql/sql_union.cc:
  st_select_lex_unit::prepare():  On failure, make sure cleanup()
  is called.

mysql-test/r/subselect.result

@@ -5005,3 +5005,15 @@ SELECT * FROM t2 UNION SELECT * FROM t2
 ORDER BY (SELECT * FROM t1 WHERE MATCH(a) AGAINST ('+abc' IN BOOLEAN MODE));
 DROP TABLE t1,t2;
 End of 5.1 tests
+#
+# Bug #57704: Cleanup code dies with void TABLE::set_keyread(bool): 
+#             Assertion `file' failed.
+#
+CREATE TABLE t1 (a INT);
+SELECT 1 FROM 
+(SELECT ROW(
+(SELECT 1 FROM t1 RIGHT JOIN 
+(SELECT 1 FROM t1, t1 t2) AS d ON 1),
+1) FROM t1) AS e;
+ERROR 21000: Operand should contain 1 column(s)
+DROP TABLE t1;

mysql-test/t/subselect.test

@@ -3946,3 +3946,21 @@ DROP TABLE t1,t2;
 --enable_result_log
 
 --echo End of 5.1 tests
+
+--echo #
+--echo # Bug #57704: Cleanup code dies with void TABLE::set_keyread(bool): 
+--echo #             Assertion `file' failed.
+--echo #
+
+CREATE TABLE t1 (a INT);
+
+--error ER_OPERAND_COLUMNS
+SELECT 1 FROM 
+  (SELECT ROW(
+    (SELECT 1 FROM t1 RIGHT JOIN 
+      (SELECT 1 FROM t1, t1 t2) AS d ON 1),
+    1) FROM t1) AS e;
+
+DROP TABLE t1;
+
+

sql/sql_union.cc

@@ -434,6 +434,7 @@ bool st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
 
 err:
   thd_arg->lex->current_select= lex_select_save;
+  (void) cleanup();
   DBUG_RETURN(TRUE);
 }