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

(cherry picked from commit f8d97a2e)

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

(cherry picked from commit 7b8b78be)

In further commit this list will be used for tracking all read
gaps, not only 'nearby'. Since this rename has rather huge
diff, let's make it in separate commit.

No logical changes.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

(cherry picked from commit d3feb691)

In our SQL implementation temporary spaces are used. They come to
MVCC engine in two variants - NULL or ephemeral. In both cases
MVCC engine must not do anything, there are several checks for
that in different parts of code.

Normalize these checks and make them similar to each other.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

(cherry picked from commit 86a8155c)

The only place where this static function is used is more general
static function - memtx_tx_track_read_story. This is a bit
confusing - usually slow variant stand for public inline 'fast'
method.

So merge both functions in one.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

(cherry picked from commit 32e41b7a)

By a mistake in 8a565144 a shortcut was added to procedure
that handles gap write: it was considered that if the writing
transaction is the same as reading - there is no actual conflict
that must be stored further. That was a wrong decision: if such
a transaction yields and another transaction comes and commits
a value with the same key - the first one must go to conflicted
state since it has read no more possible state.

Another similar mistake was made in e6f5090c, where writing
after full scan of the same transaction was not tracked as read.
Obviously that was wrong: if some other transaction overwrites
the key and commits - this transaction must go to read view since
it did not see anything by this key which is not so anymore.

Fix it, reverting the first commit and an modifying the second and
add a test.

Closes #8326

NO_DOC=bugfix

(cherry picked from commit b41c4546)

There's a special 'point hole' mechanism in mvcc transactional
manager that manages point gap reads by full key when no raw
tuple was found in the index. For instance, it's the only way
to collect gap reads for non-tree indexes.

Once a new tuple is inserted to the index, the read records are
transferred to the normal read set in the corresponding story.
Actually after that the 'point hole' record in no more needed.

So let's remove it.

While we are here, drop unused point_holes_size, improve names
and comments.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

(cherry picked from commit 62c65639)

Before this patch there were several different places in the code
that deal with referencing tuple in space, setting in_index member
and marking the story as retained or not. But logically all above
is about the same - about placing a story to the top of a chain,
i.e. the first story in version list to which index points.

This commit refactors these things a bit. This mostly relates to
two functions - memtx_tx_story_new and memtx_tx_story_link_top.

Changes in memtx_tx_story_new are based on the fact that if a story
is created by tuple, it is or immediately will be at the top of
chain. Considering this we can omit argument `is_referenced_to_pk`
and always create a story ready to be in top of chain. If a story
is already in the top - nothing else is needed; if it is to become
the top - memtx_tx_story_link_top must be called after.

Further, linking to top of chain is needed exactly in two cases:
* if a story just created by memtx_tx_story_new must become a top
* if a chain is reordered involving the top story (the top and the
  next stories are swapped)
These two cases are logically very close but still different.
Even more, previously there were two functions for that:
memtx_tx_story_link_top_light and memtx_tx_story_link_top
correspondingly. This commit introduces one function for that
(although with one more argument) that also incapsulates
activities about referencing tuples and marking stories as
retained.

After this patch the rules are logical and simple:
* if a tuple is inserted - call _story_new and _link_top(.. true).
* if a story of existing clean tuple is needed - call _story_new.
* if a chain is reordered involving top story - _link_top(.. false).

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

(cherry picked from commit 202340b7)

Remove runtime allocation error handling and use panic-on-fail
versions of allocation functions. Reasons for that:
* Memory error handling was never tested an probably doesn't work.
* Some return codes was ignored so the code had obvious flaws.
* Rollback in case of memory error made some code overcomplicated.

Part of #8648
Part of #8654

NO_DOC=no new functionality added
NO_TEST=no new functionality added
NO_CHANGELOG=no new functionalily added

(cherry picked from commit c951c9de)

Conflict trackers are used to store information that if some
transaction is committed then some another transaction must be
aborted. This happens when the first transaction writes some
key while the other reads the same key. On the other hand there
are another trackers - read trackers - that are designed to
handle exactly the same situation. That's why conflict trackers
can be simply replaced with read trackers.

That would allow to remove conflict trackers as not needed
anymore.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

(cherry picked from commit a6c2b9ff)

If addition of a tuple is rolled back while the corresponding
story is needed for something else (for example it stores a read
set of another transaction) - the story cannot be deleted.
Now there's a special flag `rollbacked` that is set to true
for such stories, and the flag must be considered in places
where history chains are scanned. That approach also requires
psn to be set for rolled-back transactions, which surprisingly
not as simple as it to say. All that makes the code complicated
and hard to maintain.

There's another approach for managing rolled back stories: simply
set their del_psn to a low enough value (lower than any existing
transaction's PSN) and (if necessary) push them to the end of
history chain. Such a story would be invisible to any transaction
due to already existing mechanisms, that's what is needed.

In order to provide "low enough" del_psn it will be natural to
assign real PSN starting from some predefined value, so any value
below that predefined value will be less that any existing PSN and
thus "low enough".

Implement this more simple approach.

Part of #8648
Part of #8654

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

(cherry picked from commit ba394a58)

That's strange, but in this test in a group of simple test cases
there are test cases that checks replaces, updates and deletes,
but occasionally there's no test case that checks inserts.

Fix it and add simple test cases for inserts.

No logical changes.

Part of #8648
Part of #8654

NO_DOC=new test case
NO_CHANGELOG=new test case

(cherry picked from commit 37b4561f)

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

(cherry picked from commit e2e5ef4b)

This reverts commit 1c0a0c90.

Cherry-picked by mistake. Tarantool 2.11 still depends on libgomp.

NO_DOC=revert
NO_TEST=revert
NO_CHANGELOG=revert

It was disabled because ligomp.a on some AArch64 systems (e.g. CentOS)
is compiled without PIC support. Now Tarantool doesn't depend on ligomp,
so it's safe to turn on PIC for AArch64 systems.

Follow-up #7536

NO_DOC=build
NO_TEST=build

(cherry picked from commit 5c1968ca)

It was disabled because dlsym tests failed when PIC is on (#7640).
However, later it turned out that the issue is not related to PIC, and
LuaJIT was turned off for such tests by commit 67e79b15 ("test: turn
LuaJIT off in tests with dlsym"). Now it's safe to turn on PIC for FreeBSD.

Follow-up #7536

NO_DOC=build
NO_TEST=build

(cherry picked from commit 05eba830)

It was decided to include the `osx_debug.yml` and `osx_release.yml`
workflows to the default tests run (without the `full-ci` label).
Now we can get test results for macOS faster and without an extra
load on CI.

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

(cherry picked from commit de404cb0)

Commit/rollback triggers are run asynchronously, upon receiving the
write status from WAL. We can't run them in the original fiber that
submitted the WAL request, because it would open a time window between
writing a transaction to WAL and committing it in tx, which could lead
to violating the cascading rolback principles. As a result,
commit/rollback triggers run with admin privileges.

The issue was already solved for confirming async transaction, but
session and user are still not correct, when the transaction is
confirmed by the limbo. Let's fix this issue by temporarily setting
session and credentials to the original fiberfor running
commit/rollback triggers.

Closes #8742

NO_DOC=bugfix

(cherry picked from commit 8cd0cd09)

Currently some transactions on synchronous space fail to complete with
the `ER_CURSOR_NO_TRANSACTION` error, when on_rollback/on_commit triggers
are set.

This is caused due to the fact, that some rollback/commit triggers
require in_txn fiber variable to be set but it's not done when a
transaction is completed from the limbo. Callbacks, which are used to
work with iterators (`lbox_txn_pairs` and `lbox_txn_iterator_next`),
acquire tnx statements from the current transactions, but they cannot
do that, when this transaction is not assigned to the current fiber, so
`ER_CURSOR_NO_TRANSACTION` is thrown.

Let's assign in_txn variable when we complete transaction from the limbo.
Moreover, let's add assertions, which check whether in_txn() is correct,
in order to be sure, that `txn_complete_success/fail` always run with
in_txn set.

Closes #8505

NO_DOC=bugfix

(cherry picked from commit 6fadc8a0)

See the docbot request for details.

Closes #7932

@TarantoolBot document
Title: correct recovery of mixed transactions

In this patch implemented correct recovery of mixed transactions. To do
this, set  `box.cfg.force_recovery` to `true`. If you need to revert to
the old behavior, don't set the `force_recovery` option.

What to do when one node feeds the other a xlog with mixed transactions?
Let there be two nodes (`node#1` and `node#2`). And let the data be
replicated from `node#1` to `node#2`. Suppose that at some point in time,
`node#1` is restoring data from an xlog containing mixed transactions. To
replicate data from `node#1` to `node#2`, do the following:
1. Stop `node#2` and delete all xlog files from it
2. Restart `node#1` by setting `force_recovery` to `true`
3. Make `node#2` rejoin to `node#1` again.

(cherry picked from commit 2b1c8713)

A new macros have been introduced because OOM errors are not handled in the
code.

Needed for #7932

NO_DOC=internal
NO_TEST=internal
NO_CHANGELOG=internal

(cherry picked from commit 53857148)

box.cfg.force_recovery used to be needed only during box.cfg() in
a few places, but its usage is going to extend.

In future commits about cluster/replicaset/instance names it will
be needed to allow rename. It won't be entirely legal (hence can't
be done without any flags), but won't be fully illegal either.

The "valid" rename will be after upgrading, when an
old cluster updated to a new version and wants to start using the
names. Then it will have to set force_recovery, set the names,
sync the instances, drop force_recovery. One-time action to allow
old installations use the new feature - the names.

Part of #5029

NO_DOC=refactoring
NO_CHANGELOG=refactoring
NO_TEST=already covered

(cherry picked from commit ae4c96c7)

After the commit a392eb76 ("box: destroy its modules even if box.cfg
not done") wal_free() on exit is called even if box.cfg() isn't finished
yet, and thus wal isn't yet enabled. This leads to a bug when wal would
unconditionally write a 00...0.xlog regardless of the actual xlog
directory contents or the actual vclock.

Let's fix this by not writing an empty xlog on exit if wal writer's
vclock is zero. It means the writer either wasn't enabled yet, or was
enabled, but hasn't written anything. In both cases writing the empty
xlog is extraneous.

Closes #8704

NO_DOC=bugfix

(cherry picked from commit f78908c9)

There was a problem in applier_wait_bootstrap_leader_uuid_is_set():
 * it didn't set an error cause when the ballot watcher was dead,
   leading to a segfault when trying to diag_add() to the cause.
 * it didn't expect the ballot watcher to exit without an error
   before the bootstrap leader uuid is known, hanging forever.

The first issue could be reproduced by trying to bootstrap a replicaset
consisting of both "old" (Tarantool 2.10 or less) and "new" instances.
Or by bootstrapping a replicaset consisting of "new" instances and
stopping some of them in a specific manner.

The second issue could be reproduced only by manually broadcasting an
empty "internal.ballot" event.

Fix both issues. The first one by setting an ER_UNKNOWN error when
the ballot watcher fiber is dead. And the second one by checking if the
ballot watcher has died during waiting for the ballot update.

The test only covers the first issue: the second one can only happen
with manual intervention and is hard to test: it involves broadcasting
an empty "internal.ballot" from the replica while it's still connecting
to remote nodes during an initial `box.cfg{}` call.

Closes #8757

NO_DOC=bugfix

(cherry picked from commit 1c25efb4)

Closes #8716

NO_DOC=bugfix

(cherry picked from commit 3d0afc60)

`string` with JOIN option is only available since CMake 3.12, but we have
developers using CMake 3.1: implement a utility `string_join` function to
remove this dependency.

Closes #5881

NO_CHANGELOG=<build fix>
NO_DOC=<build fix>
NO_TEST=<build fix>

(cherry picked from commit 55298308)

Reported by ASAN. The issue was fixed in the master branch in commit
b9550f19 ("box: support space and index names in IPROTO requests").

NO_TEST=asan
NO_DOC=bug fix
NO_CHANGELOG=minor

The xrow_decode_* functions are written in such a way that they ignore
unknown IPROTO keys. This is required for connectivity between different
Tarantool version. However, there's bug in the code connected with the
value type checking: we fail if the key is >= iproto_key_MAX. This
worked fine as long as we added new IPROTO keys in the middle of the key
space, without bumping iproto_key_MAX, but this assumption broke when we
added IPROTO_AUTH_TYPE. The issue is exacerbated by the fact that
IPROTO_AUTH_TYPE is used by IPROTO_ID, which is sent unconditionally on
connect. Let's fix the value type check and add some tests.

Notes:
 - xrow_decode_heartbeat turns out to be unused. Drop it.
 - Fix the net.box helpers response_body_decode and netbox_decode_table
   to handle unknown keys and empty body. This is needed to properly
   decode a response to an injection in tests.
 - Testing unknown keys in replication requests would be complicated.
   Instead we add a bunch of unit tests.
 - Convert the xrow unit test to TAP.

Closes #8745

NO_DOC=bug fix

(cherry picked from commit ee0660b8)

Response body decoding of DML and call/eval requests is very ad-hoc and
hard to extend: introduce a new `response_body_decode` helper that decodes
the response body similarly to `xrow_decode_dml` — this will allow to
separate decoding from processing.

Needed for #8147

NO_CHANGELOG=refactoring
NO_DOC=refactoring
NO_TEST=refactoring

(cherry picked from commit 1d6043fa)

Fix the `box-tap/gh-5602-environment-vars-cfg.test.lua` diff test after
disabling stdout bufferization in test-run.

NO_DOC=test
NO_TEST=test
NO_CHANGELOG=test

(cherry picked from commit d2d06824)

Bump test-run to new version with the following improvements:

- lint: update flake8 to 5.* [1]
- app: write test output directly to files [2]
- app: disable stdout bufferization [3]
- luatest: fix luatest command description [4]
- luatest: split stdout and stderr [5]
- luatest: write stdout to a file directly [6]
- luatest: drop a dead code [7]
- luatest: disable stdout buffering [8]
- Prettify messages about log files [9]

[1] https://github.com/tarantool/test-run/commit/4916351
[2] https://github.com/tarantool/test-run/commit/7b3c003
[3] https://github.com/tarantool/test-run/commit/48ccad8
[4] https://github.com/tarantool/test-run/commit/2756eb2
[5] https://github.com/tarantool/test-run/commit/3dab8dc
[6] https://github.com/tarantool/test-run/commit/0c24557
[7] https://github.com/tarantool/test-run/commit/036e6b6
[8] https://github.com/tarantool/test-run/commit/e65a5f8
[9] https://github.com/tarantool/test-run/commit/7a1ec4f

NO_DOC=test
NO_TEST=test
NO_CHANGELOG=test

(cherry picked from commit f0d94f8b)

Bump test-run to new version with the following improvements:

- Drop setting OMP_NUM_THREADS

Part of #3389

NO_DOC=testing stuff
NO_TEST=testing stuff
NO_CHANGELOG=testing stuff

(cherry picked from commit f65900ab)

The memtx engine has two quota consumers: `index_slab_cache` and
`slab_cache`. They both acquire SLAB_SIZE of space on first tuple
insert in "small" allocator mode, so the quota less than the slab
size times two exceeds right there.

It was decided to introduce a theoretically minimal size of the
quota and round-up any value given in box.cfg if it's less than
the lower bound.

Closes #7389

NO_DOC=bugfix

(cherry picked from commit de0731bd)

Fix the `test-sdk` job in the `submodule_update.yml` workflow according
to the new name policy for supported branches (2.10 -> release/2.10,
2.11 -> release/2.11).

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

(cherry picked from commit 83158695)

README.md in the `report-job-status` action was fixed in accordance
with the new name policy for supported branches (2.10 -> release/2.10,
2.11 -> release/2.11).

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

(cherry picked from commit fa33c5e5)

The condition for uploading test artifact to S3 was fixed in accordance
with the new name policy for supported branches (2.10 -> release/2.10,
2.11 -> release/2.11).

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

(cherry picked from commit 76c79e4e)

The condition for workflow concurrency was fixed in accordance with
the new name policy for supported branches (2.10 -> release/2.10,
2.11 -> release/2.11).

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

(cherry picked from commit 0c117197)

The push trigger in the submodule_update.yml workflow was fixed
in accordance with the new name policy for supported branches
(2.10 -> release/2.10, 2.11 -> release/2.11).

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

(cherry picked from commit 9518f322)

The push trigger for branches matching to the `[0-9].[0-9]+` pattern
was removed due to changing the name policy for supported branches
(2.10 -> release/2.10, 2.11 -> release/2.11).

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

(cherry picked from commit ba0a9f07)

- Rename the workflow into `publish-module-api-doc` to be consistent
  with other workflow names.
- Refactor workflow triggers.
- Run the workflow only on push to the tarantool/tarantool repository
  or on pull request if the 'notest' label is not set.
- Simplify condition for publishing generated API documentation.

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

(cherry picked from commit c9e0074d)