Invoke cleanup routine at the end of pfs_noop.

This commit updates the README to indicate that the "Get the code, build
it, test it" link will help decide the correct branch to work in.

Also fixes a grammar issue and cleans-up the Markdown a little bit.

Fix various typos, in comments and DEBUG statements, and code changes
are non-functional.

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.

MDEV-34226 On startup: UBSAN: applying zero offset to null pointer in my_copy_fix_mb from strings/ctype-mb.c and other locations

nullptr+0 is an UB (undefined behavior).

- Fixing my_string_metadata_get_mb() to handle {nullptr,0} without UB.
- Fixing THD::copy_with_error() to disallow {nullptr,0} by DBUG_ASSERT().
- Fixing parse_client_handshake_packet() to call THD::copy_with_error()
  with an empty string {"",0} instead of NULL string {nullptr,0}.

MDEV-30931 UBSAN: negation of -X cannot be represented in type 'long long int'; cast to an unsigned type to negate this value to itself in get_interval_value on SELECT

- Fixing the code in get_interval_value() to use Longlong_hybrid_null.
  This allows to handle correctly:

  - Signed and unsigned arguments
    (the old code assumed the argument to be signed)
  - Avoid undefined negation behavior the corner case with LONGLONG_MIN

  This fixes the UBSAN warning:
    negation of -9223372036854775808 cannot be represented
    in type 'long long int';

- Fixing the code in get_interval_value() to avoid overflow in
  the INTERVAL_QUARTER and INTERVAL_WEEK branches.
  This fixes the UBSAN warning:
    signed integer overflow: -9223372036854775808 * 7 cannot be represented
    in type 'long long int'

- Fixing the INTERVAL_WEEK branch in date_add_interval() to handle
  huge numbers correctly. Before the change, huge positive numeber
  were treated as their negative complements.
  Note, some other branches still can be affected by this problem
  and should also be fixed eventually.

- InnoDB page compression works only on COMPACT or DYNAMIC row
format tables. So InnoDB should throw error when alter table
tries to enable PAGE_COMPRESSED for redundant table.

- InnoDB should avoid printing the error message before
restoring the first page from doublewrite buffer.

Correct the second parameter for strxnmov to prevent potential buffer
overflows. The second parameter must be one less than the size of the
input buffer to avoid writing past the end of the buffer.

While the second parameter is usually correct, there are exceptions
that need fixing.

This commit addresses the issue within frm_file_exists() and other
affected places.

MDEV-28387 UBSAN: runtime error: negation of -9223372036854775808 cannot be represented in type 'long long int'; cast to an unsigned type to negate this value to itself in my_strtoll10 on SELECT

Fixing the condition to raise an overflow in the ulonglong
representation of the number is greater or equal to 0x8000000000000000ULL.
Before this change the condition did not catch -9223372036854775808
(the smallest possible signed negative longlong number).

According to https://discussions.apple.com/thread/8256853
an attempt to use AVX512 registers on macOS will result in #UD
(crash at runtime).

Also, starting with clang-18 and GCC 14, we must add "evex512" to the
target flags so that AVX and SSE instructions can use AVX512 specific
encodings. This flag was introduced together with the avx10.1-512 target.
Older compiler versions do not recognize "evex512". We do not want to
write "avx10.1-512" because it could enable some AVX512 subfeatures
that we do not have any CPUID check for.

Reviewed by: Vladislav Vaintroub
Tested on macOS by: Valerii Kravchuk

The patch for MDEV-31340 fixed the following bugs:

MDEV-33084 LASTVAL(t1) and LASTVAL(T1) do not work well with lower-case-table-names=0
MDEV-33085 Tables T1 and t1 do not work well with ENGINE=CSV and lower-case-table-names=0
MDEV-33086 SHOW OPEN TABLES IN DB1 -- is case insensitive with lower-case-table-names=0
MDEV-33088 Cannot create triggers in the database `MYSQL`
MDEV-33103 LOCK TABLE t1 AS t2 -- alias is not case sensitive with lower-case-table-names=0
MDEV-33108 TABLE_STATISTICS and INDEX_STATISTICS are case insensitive with lower-case-table-names=0
MDEV-33109 DROP DATABASE MYSQL -- does not drop SP with lower-case-table-names=0
MDEV-33110 HANDLER commands are case insensitive with lower-case-table-names=0
MDEV-33119 User is case insensitive in INFORMATION_SCHEMA.VIEWS
MDEV-33120 System log table names are case insensitive with lower-cast-table-names=0

Backporting the fixes from 11.5 to 10.5

BUF_LRU_MIN_LEN (256) is too high value for low buffer pool(BP) size.
For example, for BP size lower than 80M and 16 K page size, the limit is
more than 5% of total BP and for lowest BP 5M, it is 80% of the BP.
Non-data objects like explicit locks could occupy part of the BP pool
reducing the pages available for LRU. If LRU reaches minimum limit and
if no free pages are available, server would hang with page cleaner not
able to free any more pages.

Fix: To avoid such hang, we adjust the LRU limit lower than the limit
for data objects as checked in buf_LRU_check_size_of_non_data_objects()
i.e. one page less than 5% of BP.

trx_free_at_shutdown(): Similar to trx_t::commit_in_memory(),
clear the detailed_error (FOREIGN KEY constraint error) before
invoking trx_t::free(). We only do this on debug instrumented
builds in order to avoid a debug assertion failure on shutdown.

A wide_handler is shared among ha_spider of partitions of the same
spider table, where the last partition is designated the owner of the
wide_handler, and is responsible for its deallocation. Therefore in
case of failure, we only reset wide_handler in error handling if the
current ha_spider is the owner of the wide_handler, otherwise it will
result in segv in the destructor of ha_spider, or during
ha_spider::close().

The init, init_error, and init_error_time fields of a SPIDER_SHARE
should only be assigned when actually doing the initialisation of a
SPIDER_SHARE, otherwise they could result in spurious failures from
spider_get_share() in a subsequent statement.

- InnoDB should print the warning message saying
"Shutdown is in progress" only when shutdown state
is greater than SRV_SHUTDOWN_INITIATED.

MDEV-34187 On startup: UBSAN: runtime error: applying zero offset to null pointer in skip_trailing_space and my_hash_sort_utf8mb3_general1400_nopad_as_ci

The last element in func_array_oracle_overrides[] equal to {0,0}
was erroneously passed to Native_functions_hash::replace().
Removing this element.

Similar to #2480.
567b6812 introduced safe_strcpy() to minimize the use of C with
potentially unsafe memory overflow with strcpy() whose use is
discouraged.
Replace instances of strcpy() with safe_strcpy() where possible, limited
here to files in the `sql/` directory.

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer
Amazon Web Services, Inc.

Spider calls info with HA_STATUS_AUTO to update auto increment info,
which may attempt to connect the data node. If the connection fails,
it may emit an error and return the same error. This error should not
be of lower priority than any possible error from the later call to
handler::update_auto_increment().

Without this change, certain errors from update_auto_increment() such
as HA_ERR_AUTOINC_ERANGE may get ignored, causing my_insert() to call
my_ok(), which fails the assertion because the error was emitted in
the info() call (Diagnostics_area::is_set() returns true).

This handles the situation when one thread is still initiating a
storage engine plugin, while another is creating a table using it.

Test case failed --view protocol. Revert to using table for data
in the test.

The accounting of the limit variable that represents the
amount of space left it the buffer was incorrect.

Also there was 1 or 2 bytes left to write that occured without
the buffer length being checked.

Review: Sanja Byelkin

MariaDB-backup needs to check for SLAVE MONITOR as that is
what is returned by SHOW GRANTS.

Update test to ensure that warnings about missing privileges
do not occur when the backup is successful.

Reviewer: Andrew Hutchings
Thanks Eugene for reporting the issue.

FreeBSD doesn't like it and hangs.

As we don't wait for signal handler, let's disable SIGHUP in bootstrap
too

.opt files, unlike combinations, accumulate, let's not overuse them

followup for 13663cb5

Makes easier to add new policy to the list, and merge to newer versions-

Workaround patch: Do not remove GROUP BY clause when it has
subquer(ies) in it.

remove_redundant_subquery_clauses() removes redundant GROUP BY clause
from queries in form:
  expr IN (SELECT no_aggregates GROUP BY ...)
  expr {CMP} {ALL|ANY|SOME} (SELECT no_aggregates GROUP BY ...)
This hits problems when the GROUP BY clause itself has subquer(y/ies).

This patch is just a workaround: it disables removal of GROUP BY clause
if the clause has one or more subqueries in it.

Tests:
- subselect_elimination.test has all known crashing cases.
- subselect4.result, insert_select.result are updated.
Note that in some cases results of SELECT are changed too (not just
EXPLAINs). These are caused by non-deterministic SQL: when running a
query like:

  x > ANY( SELECT col1 FROM t1 GROUP BY constant_expression)

without removing the GROUP BY, the executor is free to pick the value
of t1.col1 from any row in the GROUP BY group (denote it $COL1_VAL).
Then, it computes x > ANY(SELECT $COL1_VAL).

When running the same query and removing the GROUP BY:

   x > ANY( SELECT col1 FROM t1)

the executor will actually check all rows of t1.

The problem was two fold:
- REPAIR TABLE t1 USE_FRM did not work for transactional
  Aria tables (Table was thought to be repaired, which it was not) which
  caused issues in later usage of the table.
- When swapping tmp_data file to data file, sort_info files where not
  updated. This caused problems if there was several unique keys and
  there was a duplicate for the second key.

Due to this bug a wrong result might be expected from queries with
an IN subquery predicate in the WHERE clause and a derived table in the
FROM clause to which split optimization could be applied.

The function JOIN::fix_all_splittings_in_plan() used the value of the
bitmap JOIN::sjm_lookup_tables() such as it had been left after the
search for the best plan for the select containing the splittable
derived table. That value could not be guaranteed to be correct. So the
recalculation of this bitmap is needed to exclude the plans with key
accesses from SJM lookup tables.

Approved by Igor Babaev <igor@maridb.com>