Disable instant ADD/DROP/reorder if indexed virtual columns exist

This works around a crash in purge.

mysql-test/suite/gcol/r/innodb_virtual_rebuild.result

@@ -7,22 +7,30 @@ ROW_FORMAT=REDUNDANT;
 INSERT INTO t4 SET i=1;
 ALTER TABLE t4 ADD INDEX(v), LOCK=NONE;
 ALTER TABLE t4 ADD COLUMN k INT, LOCK=NONE;
+ERROR 0A000: LOCK=NONE is not supported. Reason: online rebuild with indexed virtual columns. Try LOCK=SHARED
 ALTER TABLE t4 DROP k, LOCK=NONE;
+ERROR 42000: Can't DROP COLUMN `k`; check that it exists
 ALTER TABLE t4 DROP INDEX v, LOCK=NONE;
 INSERT INTO t3 SET i=1;
 ALTER TABLE t3 ADD INDEX(v), LOCK=NONE;
 ALTER TABLE t3 ADD COLUMN k INT, LOCK=NONE;
+ERROR 0A000: LOCK=NONE is not supported. Reason: online rebuild with indexed virtual columns. Try LOCK=SHARED
 ALTER TABLE t3 DROP k, LOCK=NONE;
+ERROR 42000: Can't DROP COLUMN `k`; check that it exists
 ALTER TABLE t3 DROP INDEX v, LOCK=NONE;
 INSERT INTO t2 SET i=1;
 ALTER TABLE t2 ADD INDEX(v), LOCK=NONE;
 ALTER TABLE t2 ADD COLUMN k INT, LOCK=NONE;
+ERROR 0A000: LOCK=NONE is not supported. Reason: online rebuild with indexed virtual columns. Try LOCK=SHARED
 ALTER TABLE t2 DROP k, LOCK=NONE;
+ERROR 42000: Can't DROP COLUMN `k`; check that it exists
 ALTER TABLE t2 DROP INDEX v, LOCK=NONE;
 INSERT INTO t1 SET i=1;
 ALTER TABLE t1 ADD INDEX(v), LOCK=NONE;
 ALTER TABLE t1 ADD COLUMN k INT, LOCK=NONE;
+ERROR 0A000: LOCK=NONE is not supported. Reason: online rebuild with indexed virtual columns. Try LOCK=SHARED
 ALTER TABLE t1 DROP k, LOCK=NONE;
+ERROR 42000: Can't DROP COLUMN `k`; check that it exists
 ALTER TABLE t1 DROP INDEX v, LOCK=NONE;
 connect  ddl,localhost,root,,test;
 connection default;

mysql-test/suite/gcol/t/innodb_virtual_rebuild.test

@@ -14,7 +14,10 @@ while ($n)
 {
 eval INSERT INTO t$n SET i=1;
 eval ALTER TABLE t$n ADD INDEX(v), LOCK=NONE;
+# MDEV-17468 FIXME: Fix this, and remove the 2 --error below.
+--error ER_ALTER_OPERATION_NOT_SUPPORTED_REASON
 eval ALTER TABLE t$n ADD COLUMN k INT, LOCK=NONE;
+--error ER_CANT_DROP_FIELD_OR_KEY
 eval ALTER TABLE t$n DROP k, LOCK=NONE;
 eval ALTER TABLE t$n DROP INDEX v, LOCK=NONE;
 dec $n;

storage/innobase/handler/handler0alter.cc

@@ -1059,6 +1059,21 @@ innobase_fts_check_doc_id_col(
 	return(false);
 }
 
+#if 1 // MDEV-17468: fix bugs with indexed virtual columns & remove this
+static bool has_virtual_index(const dict_table_t& table)
+{
+	const dict_index_t* index = table.indexes.start;
+	ut_ad(!index->has_virtual());
+	while ((index = index->indexes.next) != NULL) {
+		if (index->has_virtual()) {
+			ut_ad(table.n_v_cols);
+			return true;
+		}
+	}
+	return false;
+}
+#endif
+
 /** Check if InnoDB supports a particular alter table in-place
 @param altered_table TABLE object for new version of table.
 @param ha_alter_info Structure describing changes to be done
@@ -1240,6 +1255,9 @@ ha_innobase::check_if_supported_inplace_alter(
 
 	const bool supports_instant = m_prebuilt->table->supports_instant()
 		&& instant_alter_column_possible(ha_alter_info, table)
+#if 1 // MDEV-17468: fix bugs with indexed virtual columns & remove this
+		&& !has_virtual_index(*m_prebuilt->table)
+#endif
 #if 1 // MDEV-17459: adjust fts_fetch_doc_from_rec() and friends; remove this
 		&& !m_prebuilt->table->fts
 		&& !innobase_fulltext_exist(altered_table)
@@ -5700,6 +5718,9 @@ prepare_inplace_alter_table_dict(
 
 	if (ctx->need_rebuild() && user_table->supports_instant()
 	    && instant_alter_column_possible(ha_alter_info, old_table)
+#if 1 // MDEV-17468: fix bugs with indexed virtual columns & remove this
+	    && !has_virtual_index(*user_table)
+#endif
 #if 1 // MDEV-17459: adjust fts_fetch_doc_from_rec() and friends; remove this
 	    && !user_table->fts
 	    && !innobase_fulltext_exist(altered_table)