1. it is against sql way, auto-detection should use metadata, not data,
consider:

create table t1 (qwe varchar(10)) as values ('qwe'),('qw'),('q'),('werty');
select sformat('{:*>5s}', qwe) from t1;

this will auto-break on the third row.

2. using max_char_length() instead of length() fixes that, but
there's a second big issue, fmt < 8.0 doesn't natively support unicode,
so {:c} would only work for one-byte strings, for 'a', not for 'я'

because of all that let's always format strings as strings.
{:c} will only now work for numbers and still only in the ascii range.

libfmt 6.1 is in Ubuntu focal repositories.
it's easy to compile with 6.1 by doing
#define detail internal

but 6.1 also produces different results in main.func_sformat
and we want MariaDB to behave identically everywhere.

String inherits from Sql_alloc, so it's allocated on the thd's memroot,
this cannot be done per row.

Moved String[] allocation into the Item_func_sformat constructor
(not fix_fields(), because we want it on the same memroot where the item
is).

by printing a String as an std::string_view, not as a char*

* comment - use the standard style
* no need to reimplement for with while
* TODO comments for not implemented types
* rename the error not to refer to the underlying library, it's
  the implementation detail
* use res->length(0) to set length to 0, but preserve the already
  allocated buffer
* rename main.sformat -> main.func_sformat
* removed a duplicated part of the test

SFORMAT() SQL function that uses fmtlib (https://fmt.dev/)
for python-like (also Rust, C++20, etc) string formatting

Only fmtlib 7.0.0+ is supported, older fmtlib
produces different results in the test.

No native support for temporal and decimal values,
* TIME_RESULT is handled as STRING_RESULT
* DECIMAL_RESULT as REAL_RESULT

Explicitly devide two function of 0 length in the hash keys comparing.

No empty name roles exists (no sens to look for).
The problem already present in our test cases.

Prohibit user variables without name

Get rid of locking "empty" plugin.
This problem present in our tests in case of malformed frm-file, for example.

MDEV-26637: (explicit length) ASAN: main.metadata and user_variables.basic MTR failures after MDEV-26572

Use explicit length for hash record length

- Add libconfig-inifiles-perl to mariadb-client depends as mytop uses it
  https://salsa.debian.org/mariadb-team/mariadb-10.5/-/commit/7a748da87a23eb874d0bddb64114a795e9d07e6d
  http://bugs.debian.org/875708

- Make libzstd dependency versioned as RocksDB need at least 1.3.3
  https://salsa.debian.org/mariadb-team/mariadb-10.5/-/commit/da4eb54fc0c2ded0e10243fe1d81bf7e105a25c3

  However, https://github.com/facebook/rocksdb/blob/master/INSTALL.md
  implies that zstandard 1.1.3 would suffice. Version 1.3.x is available
  from Debian Stretch-backports and Ubuntu Xenial onwards.

Fixed after patch MDEV-26606 because root cause was same.

Analysis: m_current_row_for_warning is reset to 1 during cleanup phase of
stored procedure. When we perform a copy because some statement of procedure
created warning, this reset value is passed to push _warning().
Fix: Add a parameter in relevant functions to pass correct value of
error index and don't use m_current_row_for_warning directly.

statement

Not repeatable after MDEV-26606. Test case added.

procedure

Analysis: m_current_row_for_warning is reset to 1 during cleanup phase of
stored procedure. When we perform a copy because some statement of procedure
created warning, this reset value is passed to push_warning().
Hence the output is always 1.
Fix: Add a parameter in relevant functions to pass correct value of
row_number and don't use m_current_row_for_warning directly.

MDEV-22708 Assertion `!mysql_bin_log.is_open() || thd.is_current_stmt_binlog_format_row()' failed in Delayed_insert::handle_inserts and in Diagnostics_area::set_eof_status

Function `upgrade_lock_type` should check global binlog_format variable
instead of thread one.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

Updated libmariadb and enable the test.

Fixup for MDEV-10075

Analysis: ERROR_INDEX implemented in MDEV-10075 was not intuitively clear.

Fix: changed parser to use ROW_NUMBER instead of ERROR_INDEX. Removed
ERROR_INDEX and ERROR_INDEX_SYM from related files. Changed m_error_index
to m_row_number.

GCC 4.8.5 would crash when compiling trx_purge_truncate_history().
Let us try to avoid that by disabling optimizations for the function.

The test was passing some uninitialized data to libmariadb.
Mostly, the MemorySanitizer wrapper of send() detected that
some bytes were uninitialized.

The test_mdev19838() is for now disabled under MemorySanitizer,
to be fixed in MDEV-26761.

Fixes: 5c5ea59b

This is mostly working around a bad compiler optimization.

The Intel 80386 processor introduced some bit operations that would be
the perfect translation for atomic single-bit read-modify-and-write
operations. Alas, even the latest compilers as of today
(GCC 11, clang 13, Microsoft Visual C 19.29) would generate a loop around
LOCK CMPXCHG instead of emitting the instructions
LOCK BTS (fetch_or()), LOCK BTR (fetch_and()), LOCK BTC (fetch_xor()).

fil_space_t::clear_closing(): Clear the CLOSING flag.

fil_space_t::set_stopping_check(): Special variant of
fil_space_t::set_stopping() that will return the old value
of the STOPPING flag after atomically setting it.

fil_space_t::clear_stopping(): Use fetch_sub() to toggle
the STOPPING flag. The flag is guaranteed to be set upon
calling this function, hence we will toggle it to clear it.
On IA-32 and AMD64, this will translate into
the 80486 LOCK XADD instruction.

fil_space_t::check_pending_operations(): Replace a Boolean
variable with a goto label, to allow more compact code
generation for fil_space_t::set_stopping_check().

trx_rseg_t: Define private accessors ref_set() and ref_reset()
for setting and clearing the flags.

trx_lock_t::clear_deadlock_victim(), trx_lock_t::set_wsrep_victim():
Accessors for clearing and setting the flags.