MDEV-14683 Possible redundancy in error codes

ER_VERS_GENERATED_ALWAYS_NOT_EMPTY vs ER_VERS_ALTER_SYSTEM_FIELD

Related to #310 (91ba4f04).

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

@@ -375,20 +375,15 @@ a	b
 4	2
 create or replace table t (
 a int,
-sys_trx_start bigint(20) unsigned as row start invisible,
-sys_trx_end bigint(20) unsigned as row end invisible,
-period for system_time(sys_trx_start, sys_trx_end)
-) with system versioning engine innodb;
-alter table t change column sys_trx_start asdf bigint unsigned;
-ERROR HY000: Can not change system versioning field `sys_trx_start`
-create or replace table t (
-a int,
 sys_trx_start timestamp(6) as row start invisible,
 sys_trx_end timestamp(6) as row end invisible,
 period for system_time(sys_trx_start, sys_trx_end)
-) with system versioning engine myisam;
+) with system versioning;
 alter table t change column sys_trx_start asdf timestamp(6);
 ERROR HY000: Can not change system versioning field `sys_trx_start`
+insert into t values (1);
+alter table t modify column sys_trx_start bigint unsigned;
+ERROR HY000: Can not change system versioning field `sys_trx_start`
 create or replace table t (
 a int,
 sys_trx_start timestamp(6) as row start invisible,

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

@@ -260,23 +260,17 @@ select * from t for system_time all;
 insert into t values (4, 0);
 select * from t for system_time all;
 
-create or replace table t (
-  a int,
-  sys_trx_start bigint(20) unsigned as row start invisible,
-  sys_trx_end bigint(20) unsigned as row end invisible,
-  period for system_time(sys_trx_start, sys_trx_end)
-) with system versioning engine innodb;
---error ER_VERS_ALTER_SYSTEM_FIELD
-alter table t change column sys_trx_start asdf bigint unsigned;
-
 create or replace table t (
   a int,
   sys_trx_start timestamp(6) as row start invisible,
   sys_trx_end timestamp(6) as row end invisible,
   period for system_time(sys_trx_start, sys_trx_end)
-) with system versioning engine myisam;
+) with system versioning;
 --error ER_VERS_ALTER_SYSTEM_FIELD
 alter table t change column sys_trx_start asdf timestamp(6);
+insert into t values (1);
+--error ER_VERS_ALTER_SYSTEM_FIELD
+alter table t modify column sys_trx_start bigint unsigned;
 
 create or replace table t (
   a int,

sql/handler.cc

@@ -7177,6 +7177,7 @@ bool Vers_parse_info::fix_alter_info(THD *thd, Alter_info *alter_info,
     return false;
   }
 
+  if (!share->versioned)
   {
     List_iterator_fast<Create_field> it(alter_info->create_list);
     while (Create_field *f= it++)