We are going to introduce universal triggers registry and use it for
tarantool triggers (e.g. space.on_replace). However, when trigger is set
to the registry, we do not know which arguments will be passed there
from C. That is why current implementation of triggers in tarantool is not
suitable for use in universal registry.

We decided to introduce func_adapter interface which allows to call
functions from any programming language. Now we support only one
language, which is Lua, so for the most part this interface is needed
to invert dependencies.

The patch introduces func_adapter interface and its implementation for
Lua functions.

Part of #8657

NO_CHANGELOG=internal
NO_DOC=internal

`cord_slab_cache` was not designed to offer a backward compatible API, and
leaving it exposed inevitably leads to errors like those highlighted in
#7124 and tarantool/memcached#96: hence, remove it from the public API
export.

Closes #7124

@TarantoolBot document
Title: `cord_slab_cache` was removed from public API export

The `cord_slab_cache` needs to be removed from the C API reference of the
fiber module.

Space index build and space format checking operations don't destroy space
iterator on `txn_check_singlestatement` failure — fix this.

Closes #8773

NO_DOC=bugfix
NO_TEST=<leak happens in small, cannot be detected by sanitizer>

The procedure name cache uses a region for hash table entry allocation, but
the cache is a thread local variable, while the `region` uses a `slab`
allocator the lifetime of which is bounded by `main`, while thread locals
are destroyed after `main`: use the `malloc` allocator instead.

Benchmark from #7207 shows that this change does not effect performance.

Closes #8777

NO_CHANGELOG=<leak does not affect users>
NO_DOC=bugfix
NO_TEST=<detected by ASAN>

This patch removes some deprecated code. This code had no user-visible
effect, but caused problems when running the test with ASAN enabled.

Closes #8761

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

Before a commit ec1af129 ("box: do not close xlog file descriptors in
the atfork handler") there was a bug when Tarantool with enabled
background mode via environment variable could lead a crash:

NO_WRAP
```
$ TT_PID_FILE=tarantool.pid TT_LOG=tarantool.log TT_BACKGROUND=true TT_LISTEN=3301 tarantool -e 'box.cfg{}'
$ tail -3 tarantool.log
2021-11-02 16:05:43.672 [2341202] main init.c:696 E> LuajitError: cannot read stdin: Resource temporarily unavailable
2021-11-02 16:05:43.672 [2341202] main F> fatal error, exiting the event loop
2021-11-02 16:05:43.672 [2341202] main F> fatal error, exiting the event loop
```
NO_WRAP

With commit ec1af129 ("box: do not close xlog file descriptors in
the atfork handler") described bug could not be reproduced.

Proposed patch adds a test that starts Tarantool in background mode
enabled via box.cfg option and via environment variable TT_BACKGROUND to
make sure this behaviour will not be broken in a future.

Closes #6128

NO_DOC=test

This patch adds configuration examples. Although the configuration
module will be introduced later, the examples can already be tested
using the instance_config and cluster_config modules.

Closes #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This patch introduces the cluster_config module. This module contains
the cluster configuration schema.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This patch instroduces instance EE options.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance application configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance credentials configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance replication configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance snapshot configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance WAL configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance vinyl engine configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance memtx engine configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance SQL configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance database configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance iproto configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance log configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance fiber configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance console configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes the instance process configuration.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This section describes general instance configuration options.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

This patch introduces the instance_config module. This module will
contain the instance configuration schema.

Part of #8778

NO_DOC=will be added later
NO_CHANGELOG=will be added later

The msgpack module can't lack `msgpack.NULL`, because it leads to the
'Please call box.cfg{} first' error at access to `box.NULL`.

An upcoming patch regarding schemas for tarantool's new hierarchical
configuration uses `box.NULL` during tarantool's initialization.

The override feature is tested on a set of modules, which are easy to
replace with an arbitrary table without losing an ability to pass
tarantool's initialization. The msgpack module will not meet the
criteria after the mentioned patch.

The test doesn't attempt to hold a precise list of modules available for
overriding. It rather checks the overall mechanics. So it is OK to
adjust the list.

NO_DOC=testing code change
NO_CHANGELOG=see NO_DOC

There are sporadic segfaults in libunwind during backtrace_collect().
Reproducible with the latest version, and there are open issues with
similar stacks:

https://github.com/libunwind/libunwind/issues/150
https://github.com/libunwind/libunwind/issues/260
https://github.com/libunwind/libunwind/issues/473

Let's disable ENABLE_BACKTRACE for AArch64 Linux until these issues are
resolved in libunwind.

Closes #8572
Part of #8791

NO_DOC=bugfix

The ability to support backtraces is checked in cmake/compiler.cmake,
it makes no sense to duplicate the check in rpm/tarantool.spec. Also do
not enable backtraces unconditionally in apk/APKBUILD and static-build.

Part of #6998

NO_DOC=build
NO_TEST=build
NO_CHANGELOG=build

Instead of relying on fixed xlog / snap pair in gh_6794_data, let's
better generate the desired files right in the test. This way we won't
face the problem of the files getting out of date. For example, when
schema version changes.

Remove the now unneeded gh_6794_data files and re-enable the
gh_6794_recover_nonmatching_xlogs test.

Closes #8701

NO_DOC=test
NO_CHANGELOG=test

This patch fixes the crontab expression in the
Lango team stale PRs workflow, so it runs not every minute,
but every hour.

Also, python version is updated to 3.11, since the script is
reliant onto `datetime.fromisoformat' changes, that were
introduced in that version.

NO_DOC=Workflow fix
NO_TEST=Workflow fix
NO_CHANGELOG=Workflow fix

The description of CURLOPT_UPLOAD [1] is confusing:

    If you use PUT to an HTTP 1.1 server, you can upload data without
    knowing the size before starting the transfer if you use chunked
    encoding. You enable this by adding a header like
    "Transfer-Encoding: chunked" with CURLOPT_HTTPHEADER.

In fact, libcurl adds this header itself. Actually we need to avoid
adding this header by libcurl with CURLOPT_INFILESIZE [2].

The CURLOPT_UPLOAD documentation has been updated [3].

1. https://github.com/curl/curl/blob/555bacd6d522bcca497573765056354f4d5d7b33/docs/libcurl/opts/CURLOPT_UPLOAD.3
2. https://curl.se/libcurl/c/httpput.html
3. https://github.com/curl/curl/pull/11300

Closes #8744

NO_DOC=bugfix

There's case when a transaction is rolled back from prepared
state. This happens when WAL fails, synchronized replication
confirmation failure or perhaps in other similar cases. By design
other RW transactions and transactions with READ_COMMITTED
isolation level are allowed to read prepared state. All these
transactions must be aborted in case of rollback of prepared
transaction since they definitely have read no more possible
database state.

This patch implements this abortion.

Closed #8654

NO_DOC=bugfix

Rollback is rather complicated part if MVCC implementation that
is meant to handle two kinds of rollback:
* rollback from in-progress state, if box.rollback() is called.
* rollback from prepared state, when WAL fails.
Unfortunately the last one was not properly tested and surely
has at least one flaw. When an inserting transaction becomes
prepared its stories could be linked as deleted (via del_stmt
pointer) by other in-progress transactions in order to maintain
correct visibility. The problem is that in case of rollback of
such prepared transaction those links remained. Broken links
breaks the chain structure, and some older changes (that were
linked as deleted before that hapless preparation) can become
visible to other transaction.

Refactor, simplify a bit that part of code and fix the issue
described above; cover with tests.

Closes #8648

NO_DOC=bugfix

Almost completely rewrite, simplify and comment this part of code.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

Almost completely rewrite, simplify and comment this part of code.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

The latter flag is a bit wider: it reveals not only inserting
statements after deleting by the same transaction, but also
replacing and deleting statements after all kinds of previois
changes but the same transaction. This extended behavior will
be used in further commits.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

It was an ugly solution when MVCC engine requires outside engine
to set this flag which is not convenient.

Remove it and use mode arguments to set up proper read trackers.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

The function memtx_tx_story_delete is expected to delete fully
unlinked stories and thus should not try to unlink something by
itself. So remove unlink and add asserts instead.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

Now there are three kinds of very close trackers:
* The transaction have read some tuple that is not committed and
  thus not visible. This kind is now stored as gap_item with
  is_nearby = false.
* The transaction made a select or range scan, reading a key or
  range between two adjacent tuples of the index. This kind is
  stored as gap_iteam with is_nearby = true.
* A transaction completed a full scan of unordered index. This
  kind is stored as full_scan_item.

All these trackers serve for the same thing: to record a fact
that a transaction read something but didn't see anything.

There are some problems with the current solution:
* gap_item with is_nearby = false has several unused members that
  just consume space.
* bool is_nearby flag for type descriptin is an ugly solution.
* full_scan_item is separated from logically close items.

This commit joins all these trackers under one base (that is
struct gap_item_base) and solves problems above.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

Now read trackers are used both for cases when a transaction has
read an existing value and it has read nothing (read by key but
there was no visible tuple in this place). For latter case an
additional index_mask was used to identify from which index the
read was done. Along with that there was per-index interval gap
trackers.

This patch divides area of responsibility between read trackers
and gap tracker in the following way:
* Reads of existing visible values are stored in read trackers.
* Reads of non-existing or non-visible values are store in gap
  trackers.

This new approach allows to provide new invariants: gap trackers
are stored only at top of chain, and read trackers are stored
only at topmost committed story in chain.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring