Merge remote-tracking branch 'origin/10.2' into bb-10.2-ext

mysql-test/r/win.result

@@ -3161,6 +3161,19 @@ SELECT ('bar',1) IN ( SELECT c, ROW_NUMBER() OVER (PARTITION BY c) FROM t1);
 0
 DROP TABLE t1;
 #
+# MDEV-13351: Server crashes in st_select_lex::set_explain_type upon UNION with window function 
+#
+CREATE TABLE t1 (i INT);
+INSERT INTO t1 VALUES (1),(2);
+SELECT Nth_value(i,1) OVER() FROM t1 
+UNION ALL 
+( SELECT Nth_value(i,2) OVER() FROM t1 LIMIT 0 )
+;
+Nth_value(i,1) OVER()
+1
+1
+DROP TABLE t1;
+#
 # Start of 10.3 tests
 #
 #

mysql-test/t/win.test

@@ -1943,6 +1943,17 @@ INSERT IGNORE INTO t1 VALUES ('foo');
 SELECT ('bar',1) IN ( SELECT c, ROW_NUMBER() OVER (PARTITION BY c) FROM t1);
 DROP TABLE t1;
 
+--echo #
+--echo # MDEV-13351: Server crashes in st_select_lex::set_explain_type upon UNION with window function 
+--echo #
+CREATE TABLE t1 (i INT);
+INSERT INTO t1 VALUES (1),(2);
+SELECT Nth_value(i,1) OVER() FROM t1 
+UNION ALL 
+( SELECT Nth_value(i,2) OVER() FROM t1 LIMIT 0 )
+;
+DROP TABLE t1;
+
 --echo #
 --echo # Start of 10.3 tests
 --echo #

sql/sql_lex.cc

@@ -4507,10 +4507,16 @@ void st_select_lex::set_explain_type(bool on_the_fly)
           if (join)
           {
             bool uses_cte= false;
-            for (JOIN_TAB *tab= first_explain_order_tab(join); tab;
-                 tab= next_explain_order_tab(join, tab))
+            for (JOIN_TAB *tab= first_linear_tab(join, WITHOUT_BUSH_ROOTS,
+                                                       WITH_CONST_TABLES);
+                 tab;
+                 tab= next_linear_tab(join, tab, WITHOUT_BUSH_ROOTS))
             {
-              if (tab->table && tab->table->pos_in_table_list->with)
+              /*
+                pos_in_table_list=NULL for e.g. post-join aggregation JOIN_TABs.
+              */
+              if (tab->table && tab->table->pos_in_table_list &&
+                  tab->table->pos_in_table_list->with)
               {
                 uses_cte= true;
                 break;