MDEV-18869 Assertion `!((field)->vcol_info && (field)->stored_in_db())' failed...

MDEV-18869 Assertion `!((field)->vcol_info && (field)->stored_in_db())' failed in innodb_col_no upon altering table with system versioning

WITH/WITHOUT SYSTEM VERSIONING is not supported for generated columns
at parser level (see definition of field_def rule).

mysql-test/suite/versioning/r/alter.result

@@ -542,5 +542,66 @@ alter table t add check (a > 0);
 insert into t values (0);
 ERROR 23000: CONSTRAINT `CONSTRAINT_1` failed for `test`.`t`
 insert into t values (2);
+#
+# MDEV-18869 Assertion `!((field)->vcol_info && (field)->stored_in_db())' failed in innodb_col_no upon altering table with system versioning
+#
+set system_versioning_alter_history= keep;
+create or replace table t1 (a int, b int generated always as (0) stored) engine=innodb with system versioning;
+insert into t1 (a) values (1);
+alter table t1 modify a int without system versioning, algorithm=copy;
+affected rows: 1
+info: Records: 1  Duplicates: 0  Warnings: 0
+alter table t1 modify a int with system versioning, algorithm=copy;
+affected rows: 1
+info: Records: 1  Duplicates: 0  Warnings: 0
+alter table t1 modify a int without system versioning;
+affected rows: 0
+info: Records: 0  Duplicates: 0  Warnings: 0
+alter table t1 modify a int with system versioning;
+affected rows: 0
+info: Records: 0  Duplicates: 0  Warnings: 0
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` int(11) DEFAULT NULL,
+  `b` int(11) GENERATED ALWAYS AS (0) STORED
+) ENGINE=InnoDB DEFAULT CHARSET=latin1 WITH SYSTEM VERSIONING
+select * from t1;
+a	b
+1	0
+alter table t1 modify b int generated always as (0) stored without system versioning;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'without system versioning' at line 1
+alter table t1 modify b int generated always as (0) stored with system versioning;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'system versioning' at line 1
+alter table t1 modify b int without system versioning;
+affected rows: 1
+info: Records: 1  Duplicates: 0  Warnings: 0
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` int(11) DEFAULT NULL,
+  `b` int(11) DEFAULT NULL WITHOUT SYSTEM VERSIONING
+) ENGINE=InnoDB DEFAULT CHARSET=latin1 WITH SYSTEM VERSIONING
+select * from t1;
+a	b
+1	0
+create or replace table t1 (a int, b int generated always as (0) virtual) engine=innodb with system versioning;
+insert into t1 (a) values (1);
+alter table t1 modify a int without system versioning, algorithm=copy;
+affected rows: 1
+info: Records: 1  Duplicates: 0  Warnings: 0
+alter table t1 modify a int with system versioning, algorithm=copy;
+affected rows: 1
+info: Records: 1  Duplicates: 0  Warnings: 0
+alter table t1 modify a int without system versioning;
+affected rows: 0
+info: Records: 0  Duplicates: 0  Warnings: 0
+alter table t1 modify a int with system versioning;
+affected rows: 0
+info: Records: 0  Duplicates: 0  Warnings: 0
+select * from t1;
+a	b
+1	0
+affected rows: 1
 drop database test;
 create database test;

mysql-test/suite/versioning/t/alter.test

@@ -469,5 +469,39 @@ alter table t add check (a > 0);
 insert into t values (0);
 insert into t values (2);
 
+--echo #
+--echo # MDEV-18869 Assertion `!((field)->vcol_info && (field)->stored_in_db())' failed in innodb_col_no upon altering table with system versioning
+--echo #
+set system_versioning_alter_history= keep;
+create or replace table t1 (a int, b int generated always as (0) stored) engine=innodb with system versioning;
+insert into t1 (a) values (1);
+--enable_info
+alter table t1 modify a int without system versioning, algorithm=copy;
+alter table t1 modify a int with system versioning, algorithm=copy;
+alter table t1 modify a int without system versioning;
+alter table t1 modify a int with system versioning;
+--disable_info
+show create table t1;
+select * from t1;
+--enable_info
+--error ER_PARSE_ERROR
+alter table t1 modify b int generated always as (0) stored without system versioning;
+--error ER_PARSE_ERROR
+alter table t1 modify b int generated always as (0) stored with system versioning;
+alter table t1 modify b int without system versioning;
+--disable_info
+show create table t1;
+select * from t1;
+
+create or replace table t1 (a int, b int generated always as (0) virtual) engine=innodb with system versioning;
+insert into t1 (a) values (1);
+--enable_info
+alter table t1 modify a int without system versioning, algorithm=copy;
+alter table t1 modify a int with system versioning, algorithm=copy;
+alter table t1 modify a int without system versioning;
+alter table t1 modify a int with system versioning;
+select * from t1;
+--disable_info
+
 drop database test;
 create database test;

storage/innobase/handler/handler0alter.cc

@@ -8588,7 +8588,7 @@ vers_change_fields_cache(
 	    ha_alter_info->alter_info->create_list);
 
 	while (const Create_field* create_field = it++) {
-		if (!create_field->field) {
+		if (!create_field->field || create_field->field->vcol_info) {
 			continue;
 		}
 		dict_col_t* col = dict_table_get_nth_col(