MDEV-37422: SIGSEGV / Assert for vcol substitution in GROUP BY WITH ROLLUP

Variant 2:
Do not do virtual column substitution in GROUP BY when WITH ROLLUP is
present.

Approved by: Yuchen Pei <ycp@mariadb.com>

Author: spetrunia

mysql-test/suite/vcol/r/order_by_group_by_subst.result

@@ -222,3 +222,19 @@ a	b
 5	4
 5	5
 drop table t1, t2;
+#
+# MDEV-37422: SIGSEGV failed in base_list_iterator::replace, Assertion `n < m_size'
+#   in Baounds_checked_array, ASAN use-after-poison in JOIN::rollup_make_fields
+#
+CREATE TABLE t1 (
+a INT,
+b INT,
+a1 INT GENERATED ALWAYS AS (a) VIRTUAL,
+INDEX (a1)
+) ENGINE=INNODB;
+SELECT * FROM t1 GROUP BY a WITH ROLLUP;
+a	b	a1
+drop table t1;
+#
+# End of 12.1 tests
+#

mysql-test/suite/vcol/t/order_by_group_by_subst.test

@@ -168,3 +168,22 @@ insert into t1 (a) select seq from seq_1_to_5;
 insert into t2 (b) select seq from seq_1_to_5;
 SELECT a, b FROM t1, t2 GROUP BY a, b HAVING a>2 and b>2;
 drop table t1, t2;
+
+--echo #
+--echo # MDEV-37422: SIGSEGV failed in base_list_iterator::replace, Assertion `n < m_size'
+--echo #   in Baounds_checked_array, ASAN use-after-poison in JOIN::rollup_make_fields
+--echo #
+--source include/have_innodb.inc
+CREATE TABLE t1 (
+  a INT,
+  b INT,
+  a1 INT GENERATED ALWAYS AS (a) VIRTUAL,
+  INDEX (a1)
+) ENGINE=INNODB;
+
+SELECT * FROM t1 GROUP BY a WITH ROLLUP;
+drop table t1;
+
+--echo #
+--echo # End of 12.1 tests
+--echo #

sql/opt_vcol_substitution.cc

@@ -303,7 +303,11 @@ bool substitute_indexed_vcols_for_join(JOIN *join)
   ctx.subst_count= 0;
   if (join->order)
     subst_vcols_in_order(&ctx, join->order, join, false);
-  if (join->group_list)
+  /*
+    Do not do substitution for WITH ROLLUP as that breaks some of its data
+    structures.
+  */
+  if (join->group_list && join->rollup.state == st_rollup::STATE_NONE)
     subst_vcols_in_order(&ctx, join->group_list, join, true);
   if (ctx.subst_count)
   {