The problem described in the bug report happened because the code
did not test check_cols(1) after fix_fields() in a few places.

Additionally, fix_fields() could be called multiple times for SP variables,
because they are all fixed at a early stage in append_for_log().

Solution:
1. Adding a few helper methods
   - fix_fields_if_needed()
   - fix_fields_if_needed_for_scalar()
   - fix_fields_if_needed_for_bool()
   - fix_fields_if_needed_for_order_by()
  and using it in many cases instead of fix_fields() where
  the "fixed" status is not definitely known to be "false".

2. Adding DBUG_ASSERT(!fixed) into Item_splocal*::fix_fields()
   to catch double execution.

3. Adding tests.

As a good side effect, the patch removes a lot of duplicate code (~60 lines):

   if (!item->fixed &&
       item->fix_fields(..) &&
       item->check_cols(1))
     return true;

After a failed ADD INDEX, dict_index_remove_from_cache_low()
could iterate the index fields and dereference a freed virtual
column object when trying to remove the index from the v_indexes
of the virtual column.

This regression was caused by a merge of
MDEV-16119 InnoDB lock->index refers to a freed object.

ha_innobase_inplace_ctx::clear_added_indexes(): Detach the
indexes of uncommitted indexes from virtual columns, so that
the iteration in dict_index_remove_from_cache_low() can be avoided.

ha_innobase::prepare_inplace_alter_table(): Ignore uncommitted
corrupted indexes when rejecting ALTER TABLE. (This minor bug was
revealed by the extension of the test case.)

dict_index_t::detach_columns(): Detach an index from virtual columns.
Invoked by both dict_index_remove_from_cache_low() and
ha_innobase_inplace_ctx::clear_added_indexes().

dict_col_t::detach(const dict_index_t& index): Detach an index from
a column.

dict_col_t::is_virtual(): Replaces dict_col_is_virtual().

dict_index_t::has_virtual(): Replaces dict_index_has_virtual().

restore its original semantics by allowing only columns
in the write_set. Generated columns work around the assert
by temporarily updating the write_set.

use a read_set instead. a bit in the read_set means "the field
value is needed" (read or generated, whatever it takes).

don't read all columns from the source table, but only
those that the will be inserted into the target table
and cannot be generated by the target table.

test case is in the following commits

don't set bits in the vcol_set of the wrong table

O_TMPFILE creates a tempfile not attached to a filename.

This is what we want for MY_TEMPORARY.

We preserve a state O_TMPFILE_works, because kernel version or
filesystem could cause failure.

Closes #662

log_crypt_101_read_block(): Mimic MariaDB 10.1, and use the first
encryption key if the key for the checkpoint cannot be found.
Redo log encryption key rotation was ultimately disabled
in MDEV-9422 (MariaDB 10.1.13) due to design issues. So, from
MariaDB 10.1.13 onwards only one log encryption key should matter.

recv_log_format_0_recover(): Add the parameter 'bool crypt'.
Indicate when the log cannot be decrypted for upgrade, instead of
making a possibly false claim that the log requires crash recovery.

init_crypt_key(): Remove extra space from a message.

just before they're sent to the client. Because mysql->host
value is known only after the connection is established,
and it's needed for the "_sever_host" attribute.

This fixes ASAN use-after-free warning in rpl tests

followup for ee8dfc68

MDEV-15991 Server crashes in setup_on_expr upon calling SP or function executing DML on versioned tables

Do not try to set versioning conditions on every SP call. It may work
incorrectly, but it's a general bug described in MDEV-774.
This patch makes system versioning stuff consistent with other code and
also fixes a use-after-free bug.

Closes #756

* Always-false vers_select_conds_t::from_query
* Debug helpers

Closes #684

This partially reverts commit dc0a7660.

Make mariadb crc32 lib platform independent

It looks strange that someone can make use of 2 crc libraries
(Power64 or AArch64) at the same time.

The patch sets macros 'CRC32_LIBRARY' to make platform independence as an optional crc32 library.

Change-Id: I68bbf73cafb6a12f7fb105ad57d117b114a8c4af
Signed-off-by: Yuqi Gu <yuqi.gu@arm.com>

Just spacing out the links on separate linkes, they were running together
in a block of text and could be a little hard for some people to
differentiate where one begins and the next ends. Seems silly, but just
trying to help in the formatting a bit.

This bug caused crashes for queries with unreferenced non-recursive
CTEs specified by unions.It happened because the function
st_select_lex_unit::prepare() tried to use the value of the field 'derived'
that could not be set for unferenced CTEs as there was no derived
table associated with an unreferenced CTE.

INNOBASE_DEFAULTS: Replace ALTER_ADD_COLUMN with the more appropriate
ALTER_ADD_STORED_BASE_COLUMN. This clean-up causes no change of
behaviour, because ALGORITHM=INPLACE would be refused for
ALTER_ADD_STORED_GENERATED_COLUMN, and default values are not computed
nor substituted for ALTER_ADD_VIRTUAL_COLUMN.

Now the boolean data type is preserved in hybrid functions and MIN/MAX,
so COALESCE(bool_expr,bool_expr) and MAX(bool_expr) are correctly
detected by JSON_OBJECT() as being boolean rather than numeric expressions.

Disable /permissive- flag, so MFC  is found, and upgrade_wizard is built.

MFC code is not standard C++, so it doesn not play well with /permissive-

commit 2dbeebdb accidentally changed
ALTER_COLUMN_OPTION and ALTER_COLUMN_STORAGE_TYPE to be separate flags.
InnoDB and Mroonga are only checking for the latter;
the example storage engine is checking for the former only.

The impact of this bug should be incorrect operation of Mroonga when
the column options GROONGA_TYPE, FLAGS are changed.

InnoDB does not define any column options, only table options,
so the flag ALTER_COLUMN_OPTION should never have been set.

Also, remove the unused flag ALTER_DROP_HISTORICAL.

- Adding Type_handler::traditional_merge_field_type()
- Removing real_type_to_type(), field_merge_type()
- Making Type_handler_var_string to merge as VARCHAR
- Additionally, fixing Field_string::print() to add the "/*old*/"
  comment into the data type for the old VARCHAR.
  This is similar to what MDEV-8267 earlier did for old DECIMAL.
- Adding tests

Fix type mismatches in the unit test mdev10259().

btr_search_info_get_ref_count(): Do not return early if !table->space.
We can simply access table->space_id even after the tablespace has
been discarded.

btr_get_search_latch(): Relax a debug assertion to allow
!index->table->space.

Include all the Makefiles that define variables that can be useful
within debian/rules. This includes buildflags.mk as well.

Use the standard variable names and don't define our own.

For details see https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=852728

For details see https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=865737