must behave as any other generated column: an error in the strict mode,
a warning otherwise.

sys_trx_start -> row_start
sys_trx_end -> row_end

use system time, not @@timestamp

rename to test_versioning
set maturity to experimental

same change as for PSI_TABLE_CALL

it's correct, they preserve their documented names

remove unused error messages
reword ER_VERS_SYS_FIELD_NOT_HIDDEN->ER_VERS_SYS_FIELD_EXISTS

Many related changes.

Note that AS OF condition must always be pushed down to physical tables,
it cannot be applied to a derived or a view. Thus:

* no versioning for internal temporary tables, they can never store
  historical data.
* remove special versioning code from mysql_derived_prepare and
  remove ER_VERS_DERIVED_PROHIBITED - derived can have no historical
  data and cannot be prohibited for system versioning related reasons.
* do not expand select list for derived/views with sys vers fields,
  derived/views can never have historical data.
* remove special invisiblity rules for sys vers fields, they are no
  longer needed after the previous change
* remove system_versioning_hide, it lost the meaning after the
  previous change.
* remove ER_VERS_SYSTEM_TIME_CLASH, it's no "clash", the inner
  AS OF clause always wins.
* non-versioned fields in a historical query

reword the warning text, downgrade to note, don't
replace values with NULLs

CTE don't work, report MDEV-14820

compiler warning (mix of bool and enum in ?:)

MDEV-14821 Assertion `!is_set() || (m_status == DA_OK_BULK && is_bulk_op())` failed in Diagnostics_area::set_ok_status

MDEV-14817 Server crashes in prep_alter_part_table() after table lock and multiple add partition [fixes #440]

Cause: `table->part_info` is stale after `prep_alter_part_table()` while
`table->m_needs_reopen == true`.

Fix: restore `table->part_info` in case of error in `prep_alter_part_table()`.

Tested with main, parts, innodb suites.

MDEV-14769 Temporary table can be altered into system versioning + system_versioning_alter_history has no effect

MDEV-14786 Server crashes in Item_cond::transform on 2nd execution of SP querying from a view [fixes #436]

move table->vers_update_fields() where it belongs - into fill_record(),
right after table_arg->update_virtual_fields()

MDEV-14744 Assertion `table->versioned() == m_prebuilt->table->versioned()' failed in ha_innobase::open

SQL: TABLE_LIST cleanup on free_tmp_table()

May affect non-versioning tests (main suite passed).

Invalidate via ULONG_MAX was wrong because sp_cache_flush_obsolete()
works incorrectly in this case.

Fixes MDEV-14749

in row_truncate_table_for_mysql()