BUG#818280: crash in do_copy_not_null() in maria-5.3 with semijoin

- Make simplify_joins() set maybe_null=FALSE for tables that were on the 
  inner sides of inner joins and then were moved to the inner sides of semi-joins.

mysql-test/r/subselect_sj.result

@@ -1715,4 +1715,18 @@ f1	f2	f3	f3
 0	NULL	NULL	NULL
 DROP TABLE t1, t2, t3, t4;
 set @tmp803457=@@optimizer_switch;
+#
+# BUG#818280: crash in do_copy_not_null() in maria-5.3 with semijoin
+#
+CREATE TABLE t1 ( c1 int NOT NULL , c2 int NOT NULL, PRIMARY KEY (c1)) ;
+INSERT IGNORE INTO t1 VALUES (2,7),(1,3),(5,6);
+CREATE TABLE t3 ( c1 int NOT NULL , c2 int NOT NULL, PRIMARY KEY (c1)) ;
+INSERT IGNORE INTO t3 VALUES (2,7),(1,3),(5,6);
+CREATE TABLE t2 ( c1 int NOT NULL , c5 int NOT NULL );
+INSERT IGNORE INTO t2 VALUES (2,2),(2,2),(5,6);
+SELECT * FROM t1 WHERE c1 IN ( SELECT t3.c1 FROM t3 LEFT JOIN t2 ON t2 .c1 = t3 .c1 WHERE t2.c5 != 0 );
+c1	c2
+2	7
+5	6
+DROP TABLE t1, t2, t3;
 set optimizer_switch=@subselect_sj_tmp;

mysql-test/r/subselect_sj_jcl6.result

@@ -1726,6 +1726,20 @@ f1	f2	f3	f3
 0	NULL	NULL	NULL
 DROP TABLE t1, t2, t3, t4;
 set @tmp803457=@@optimizer_switch;
+#
+# BUG#818280: crash in do_copy_not_null() in maria-5.3 with semijoin
+#
+CREATE TABLE t1 ( c1 int NOT NULL , c2 int NOT NULL, PRIMARY KEY (c1)) ;
+INSERT IGNORE INTO t1 VALUES (2,7),(1,3),(5,6);
+CREATE TABLE t3 ( c1 int NOT NULL , c2 int NOT NULL, PRIMARY KEY (c1)) ;
+INSERT IGNORE INTO t3 VALUES (2,7),(1,3),(5,6);
+CREATE TABLE t2 ( c1 int NOT NULL , c5 int NOT NULL );
+INSERT IGNORE INTO t2 VALUES (2,2),(2,2),(5,6);
+SELECT * FROM t1 WHERE c1 IN ( SELECT t3.c1 FROM t3 LEFT JOIN t2 ON t2 .c1 = t3 .c1 WHERE t2.c5 != 0 );
+c1	c2
+2	7
+5	6
+DROP TABLE t1, t2, t3;
 set optimizer_switch=@subselect_sj_tmp;
 #
 # BUG#49129: Wrong result with IN-subquery with join_cache_level=6 and firstmatch=off

mysql-test/t/subselect_sj.test

@@ -1555,5 +1555,21 @@ SELECT * FROM t1 NATURAL LEFT JOIN (t2, t3 ) WHERE IFNULL(t2.f3,'foo') IN (SELEC
 DROP TABLE t1, t2, t3, t4;
 set @tmp803457=@@optimizer_switch;
 
+--echo #
+--echo # BUG#818280: crash in do_copy_not_null() in maria-5.3 with semijoin
+--echo #
+CREATE TABLE t1 ( c1 int NOT NULL , c2 int NOT NULL, PRIMARY KEY (c1)) ;
+INSERT IGNORE INTO t1 VALUES (2,7),(1,3),(5,6);
+
+CREATE TABLE t3 ( c1 int NOT NULL , c2 int NOT NULL, PRIMARY KEY (c1)) ;
+INSERT IGNORE INTO t3 VALUES (2,7),(1,3),(5,6);
+
+CREATE TABLE t2 ( c1 int NOT NULL , c5 int NOT NULL );
+INSERT IGNORE INTO t2 VALUES (2,2),(2,2),(5,6);
+
+SELECT * FROM t1 WHERE c1 IN ( SELECT t3.c1 FROM t3 LEFT JOIN t2 ON t2 .c1 = t3 .c1 WHERE t2.c5 != 0 );
+
+DROP TABLE t1, t2, t3;
+
 # The following command must be the last one the file 
 set optimizer_switch=@subselect_sj_tmp;

sql/sql_select.cc

@@ -11928,6 +11928,18 @@ simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top,
          leave it intact (otherwise it is flattened)
        */
       join->select_lex->sj_nests.push_back(table);
+
+      /* 
+        Also, walk through semi-join children and mark those that are now
+        top-level
+      */
+      TABLE_LIST *tbl;
+      List_iterator<TABLE_LIST> it(nested_join->join_list);
+      while ((tbl= it++))
+      {
+        if (!tbl->on_expr && tbl->table)
+          tbl->table->maybe_null= FALSE;
+      }
     }
     else if (nested_join && !table->on_expr)
     {