MDEV-29360 Crash when pushing condition with always false IS NULL into derived

Variant 2. Preliminary patch.

mysql-test/main/derived_cond_pushdown.result

@@ -19051,4 +19051,27 @@ EXPLAIN
   }
 }
 drop table t1, t2;
+#
+# MDEV-29360: Pushed condition contains always false IS NULL
+#
+CREATE TABLE t1 (a int NOT NULL);
+INSERT INTO t1 VALUES (0),(1),(3);
+CREATE TABLE t2 SELECT a as b  FROM t1;
+CREATE TABLE t3 SELECT a as c FROM t1;
+SELECT * FROM (SELECT a FROM t1 GROUP BY a) dt1, (SELECT b FROM t2) dt2, t3
+WHERE dt2.b = t3.c AND dt1.a BETWEEN 0 AND (dt2.b IS NULL);
+a	b	c
+0	0	0
+0	1	1
+0	3	3
+SELECT * FROM (SELECT a FROM t1 GROUP BY a) dt1, (SELECT b FROM t2) dt2, t3
+WHERE dt2.b = t3.c AND dt1.a BETWEEN 0 AND (1+(dt2.b IS NULL));
+a	b	c
+0	0	0
+1	0	0
+0	1	1
+1	1	1
+0	3	3
+1	3	3
+DROP TABLE t1,t2,t3;
 # End of 10.5 tests

mysql-test/main/derived_cond_pushdown.test

@@ -4188,4 +4188,20 @@ execute stmt;
 
 drop table t1, t2;
 
+--echo #
+--echo # MDEV-29360: Pushed condition contains always false IS NULL
+--echo #
+
+CREATE TABLE t1 (a int NOT NULL);
+INSERT INTO t1 VALUES (0),(1),(3);
+CREATE TABLE t2 SELECT a as b  FROM t1;
+CREATE TABLE t3 SELECT a as c FROM t1;
+
+SELECT * FROM (SELECT a FROM t1 GROUP BY a) dt1, (SELECT b FROM t2) dt2, t3
+  WHERE dt2.b = t3.c AND dt1.a BETWEEN 0 AND (dt2.b IS NULL);
+SELECT * FROM (SELECT a FROM t1 GROUP BY a) dt1, (SELECT b FROM t2) dt2, t3
+  WHERE dt2.b = t3.c AND dt1.a BETWEEN 0 AND (1+(dt2.b IS NULL));
+
+DROP TABLE t1,t2,t3;
+
 --echo # End of 10.5 tests

sql/item.cc

@@ -7963,6 +7963,8 @@ Item_direct_view_ref::grouping_field_transformer_for_where(THD *thd,
   st_select_lex *sel= (st_select_lex *)arg;
   Field_pair *gr_field= find_matching_field_pair(this,
                                                  sel->grouping_tmp_fields);
+  if (!gr_field)
+    return this;
   return gr_field->corresponding_item->build_clone(thd);
 }