BUG#952297: Server crashes on 2nd execution of PS in Field::is_null with semijoin+materialization

- The bug would show up 
   - when using PS (so that we get re-execution)
   - the left_expr of the subquery is a reference to viewname.column_name, so that it crashes
      when one tries to use it without having called fix_fields for it.
   - when using SJ-Materialization, which makes use of sj_subq_pred->left_expr expression

- The fix is to have setup_conds() fix sj_subq_pred->left_expr for semi-join nests it finds.

mysql-test/r/subselect_mat.result

@@ -1912,6 +1912,28 @@ WHERE a IN (SELECT MAX(c) FROM t2 WHERE c < 4) AND b=7 AND (a IS NULL OR a=b);
 a	b
 SET optimizer_switch=@save_optimizer_switch;
 DROP TABLE t1,t2;
+#
+# BUG#952297: Server crashes on 2nd execution of PS in Field::is_null with semijoin+materialization
+#
+CREATE TABLE t1 ( a VARCHAR(1) );
+INSERT INTO t1 VALUES ('y'),('z');
+CREATE TABLE t2 ( b VARCHAR(1), c VARCHAR(1) );
+INSERT INTO t2 VALUES ('v','v'),('v','v');
+CREATE VIEW v2 AS SELECT * FROM t2;
+PREPARE ps FROM '
+SELECT a FROM t1, v2
+WHERE ( c, b ) IN ( SELECT b, b FROM t2 )
+GROUP BY a ';
+EXECUTE ps;
+a
+y
+z
+EXECUTE ps;
+a
+y
+z
+DROP VIEW v2;
+DROP TABLE t1, t2;
 # This must be at the end:
 set optimizer_switch=@subselect_sj_mat_tmp;
 set join_cache_level=@save_join_cache_level;

mysql-test/r/subselect_sj_mat.result

@@ -1950,6 +1950,28 @@ WHERE a IN (SELECT MAX(c) FROM t2 WHERE c < 4) AND b=7 AND (a IS NULL OR a=b);
 a	b
 SET optimizer_switch=@save_optimizer_switch;
 DROP TABLE t1,t2;
+#
+# BUG#952297: Server crashes on 2nd execution of PS in Field::is_null with semijoin+materialization
+#
+CREATE TABLE t1 ( a VARCHAR(1) );
+INSERT INTO t1 VALUES ('y'),('z');
+CREATE TABLE t2 ( b VARCHAR(1), c VARCHAR(1) );
+INSERT INTO t2 VALUES ('v','v'),('v','v');
+CREATE VIEW v2 AS SELECT * FROM t2;
+PREPARE ps FROM '
+SELECT a FROM t1, v2
+WHERE ( c, b ) IN ( SELECT b, b FROM t2 )
+GROUP BY a ';
+EXECUTE ps;
+a
+y
+z
+EXECUTE ps;
+a
+y
+z
+DROP VIEW v2;
+DROP TABLE t1, t2;
 # This must be at the end:
 set optimizer_switch=@subselect_sj_mat_tmp;
 set join_cache_level=@save_join_cache_level;

mysql-test/t/subselect_sj_mat.test

@@ -1602,6 +1602,28 @@ SET optimizer_switch=@save_optimizer_switch;
 
 DROP TABLE t1,t2;
 
+--echo #
+--echo # BUG#952297: Server crashes on 2nd execution of PS in Field::is_null with semijoin+materialization
+--echo #
+CREATE TABLE t1 ( a VARCHAR(1) );
+INSERT INTO t1 VALUES ('y'),('z');
+
+CREATE TABLE t2 ( b VARCHAR(1), c VARCHAR(1) );
+INSERT INTO t2 VALUES ('v','v'),('v','v');
+
+CREATE VIEW v2 AS SELECT * FROM t2;
+
+PREPARE ps FROM '
+SELECT a FROM t1, v2
+WHERE ( c, b ) IN ( SELECT b, b FROM t2 )
+GROUP BY a ';
+
+EXECUTE ps;
+EXECUTE ps;
+
+DROP VIEW v2;
+DROP TABLE t1, t2;
+
 --echo # This must be at the end:
 set optimizer_switch=@subselect_sj_mat_tmp;
 set join_cache_level=@save_join_cache_level;

sql/sql_base.cc

@@ -8497,6 +8497,17 @@ int setup_conds(THD *thd, TABLE_LIST *tables, List<TABLE_LIST> &leaves,
 	  goto err_no_arena;
         select_lex->cond_count++;
       }
+      /*
+        If it's a semi-join nest, fix its "left expression", as it is used by
+        the SJ-Materialization
+      */
+      if (embedded->sj_subq_pred)
+      {
+        Item **left_expr= &embedded->sj_subq_pred->left_expr;
+        if (!(*left_expr)->fixed && (*left_expr)->fix_fields(thd, left_expr))
+          goto err_no_arena;
+      }
+
       embedding= embedded->embedding;
     }
     while (embedding &&