Problem with W214 in src/box/lua/net_box.lua was fixed in previous
commit. Can bump luacheck version now.

NO_DOC=testing
NO_TEST=testing
NO_CHANGELOG=testing

Since 0.26.0 luacheck emits a warning on the `_box` variable.
From luacheck v.0.26.0 release notes:

"Function arguments that start with a single underscore
get an "unused hint". Leaving them unused doesn't result
in a warning. Using them, on the other hand, is a
new warning (№ 214)."

Renamed `_box` to `__box`, which isn't considered unused.

Closes #7304.

NO_DOC=testing
NO_TEST=testing
NO_CHANGELOG=testing

We must not throw exceptions from C code.

Currently, there's the only C function that uses diag_raise() - it's
space_cache_find_xc. We move it under ifdef(__cplusplus).

Follow-up #4735

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

current_session() is called from C code so it must not throw, but it may
if it fails to allocate a session. Practically, this is hardly possible,
because we don't limit the runtime arena, which is used for allocation
of session objects. Still, this looks potentially dangerous.

Gracefully handling an allocation failure in all places where
current_session() may be called would be complicated. Since it's more of
a theoretical issue, let's panic on a session allocation error, like we
do if we fail to allocate other mission critical system objects.

Closes #4735

NO_DOC=code health
NO_TEST=code health
NO_CHANGELOG=code health

The functions allocate and free a session so they should be called
new/delete, not create/destroy accroding to our naming convention.
While we are at it, also delete obsoleve comments to these functions:
they don't invoke session triggers.

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

C++ features are not used in this file.

Note, we need to move ifdef(__cplusplus) in user.h to make guest_user
and admin_user variables accessible from C code.

Also, we need to move initialization of session_vtab_registry to
session_init(), because most C compilers don't allow to initialize
a global variable with a value of another global variable.

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

Our txn_limbo_is_replica_outdated check works correctly only when there
is a stream of PROMOTE requests. Only the author of the latest PROMOTE
is writable and may issue transactions. No matter synchronous or
asynchronous.

So txn_limbo_is_replica_outdated assumes that everyone but the node with
the greatest PROMOTE/DEMOTE term is outdated.

This isn't true for DEMOTE requests. There is only one server which
issues the DEMOTE request, but once it's written, it's fine to accept
asynchronous transactions from everyone.

Now the check is too strict. Every time there is an asynchronous
transaction from someone, who isn't the author of the latest PROMOTE or
DEMOTE, replication is broken with ER_SPLIT_BRAIN.

Let's relax it: when limbo owner is 0, it's fine to accept asynchronous
transactions from everyone, no matter the term of their latest PROMOTE
and DEMOTE.

This means that now after a DEMOTE we will miss one case of true
split-brain: when old leader continues writing data in an obsolete term,
and the new leader first issues PROMOTE and then DEMOTE.

This is a tradeoff for making async master-master work after DEMOTE.

The completely correct fix would be to write the term the transaction
was written in with each transaction and replace
txn_limbo_is_replica_outdated with txn_limbo_is_request_outdated, so
that we decide whether to filter the request or not judging by the term
it was applied in, not by the term we seen in some past PROMOTE from the
node. This fix seems too costy though, given that we only miss one case
of split-brain at the moment when the user enables master-master
replication (by writing a DEMOTE). And in master-master there is no such
thing as a split-brain.

Follow-up #5295
Closes #7286

NO_DOC=internal chcange

Currently there's only one place where applier_synchro_filter_tx
accesses limbo state under a latch: this place is
txn_limbo_is_replica_outdated. Soon there will be more accesses to limbo
parameters and all of them should be guarded as well.

Let's simplify things a bit and guard the whole synchro_filter_tx with
the limbo latch.

While we are at it remove txn_limbo_is_replica_outdated as not needed
anymore.

Part-of #7286

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

Starting with commit deca9749
("replication: unify replication filtering with and without elections")
The filter works always, even when elections are turned off.

Reflect that in the comments for applier_synchro_filter_tx and
txn_limbo_is_replica_outdated.

Follow-up #6133

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

The 'small' lib test suite was not run for out-of-source builds since
the wrong symlink was created for test binaries and test-run couldn't
find them. Now it is fixed.

When test-run loads tests, first, it searches the suite.ini file and if
it exists test-run consider the dir as a test suite. So there was sense
to create a permanent link for 'small' lib tests.

Closes #4485

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

Disable tests while building packages in the reusable_build.yml workflow
to speed up the build process in integration testing for tarantool and
modules/connectors.

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

Sometimes we need to disable testing while building deb/rpm packages to
speed up the build process. Now it is possible via `MAKE_CHECK` env var.
By default, testing is on, but if one defines `MAKE_CHECK=false`, tests
will be off.

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

This patch adds the tzdata package as a dependency for DEB/RPM tarantool
package since some tarantool datetime functionality needs this.

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

Now the test-run dependencies (pyyaml, gevent) have the corresponding
deb packages installable via the 'apt' package manager and finally it's
time to enable running tests in the package build process.

Closes #1341

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

Vinyl doesn't support the hot standby mode. There's a ticket to
implement it, see #2013. The behavior is undefined if running an
instance in the hot standby mode in case the master has Vinyl spaces.
It may result in a crash or even data corruption.

Let's raise an explicit error in this case.

Closes #6565

NO_DOC=bug fix

Since commit d2537d9d ("relay: cleanup error handling")
recover_remaining_wals() doesn't log the error it throws -
now callers of this function should catch and log the error.
hot_standby_f() doesn't catch the error so the diagnostic
message is lost if we fail to apply a row in the hot standby
mode. Fix this.

NO_DOC=bug fix
NO_TEST=checked in next commit
NO_CHANGELOG=minor bug in logging

If a nested tuple field is indexed, it can be accessed by [*] aka
multikey or any token:

  s = box.schema.create_space('test')
  s:create_index('pk')
  s:create_index('sk', {parts = {{2, 'unsigned', path = '[1][1]'}}})
  t = s:replace{1, {{1}}}
  t['[2][1][*]'] -- returns 1!

If a nested field isn't indexed (remove creation of the secondary index
in the example above), then access by [*] returns nil.

Call graph:

  lbox_tuple_field_by_path:
    tuple_field_raw_by_full_path
      tuple_field_raw_by_path
        tuple_format_field_by_path
          json_tree_lookup_entry
            json_tree_lookup

And json_tree_lookup matches the first node if the key is [*].
We shouldn't match anything to [*].

Closes #5226

NO_DOC=bug fix

__gcov_flush was removed in gcc11.

Since gcc11 __gcov_dump calls __gcov_lock at the start and
__gcov_unlock before returning. Same is true for __gcov_reset.
Because of that using __gcov_reset right after __gcov_dump since gcc11
is the same as using __gcov_flush before gcc11.

Closes #7302

NO_CHANGELOG=internal
NO_DOC=internal
NO_TEST=internal

Covered most of box_promote and box_demote with tests:
1. Promote/demote unconfigured box
2. Promoting current leader with elections on and off
3. Demoting follower with elections on and off
4. Promoting current leader, but not limbo owner with elections on
5. Demoting current leader with elections on and off
6. Simultaneous promote/demote
7. Promoting voter
8. Interfering promote/demote while writing new term to wal
9. Interfering promote/demote while waiting for synchro queue
   to be emptied
10. Interfering promote while waiting for limbo to be acked
    (similar to replication/gh-5430-qsync-promote-crash.test.lua)

Closes #6033

NO_DOC=testing stuff
NO_CHANGELOG=testing stuff

The test failed with the following output:

 TAP version 13
 1..3
 # Started on Tue Jun 28 13:36:03 2022
 # Starting group: pre-vote
 not ok 1	pre-vote.test_no_direct_connection
 #   .../election_pre_vote_test.lua:46: expected: a value evaluating to
					true, actual: false
 #   stack traceback:
 #   .../election_pre_vote_test.lua:65: in function 'retrying'
 #   .../election_pre_vote_test.lua:64: in function
				    'pre-vote.test_no_direct_connection'
 #   ...
 #   [C]: in function 'xpcall'
 ok     2	pre-vote.test_no_quorum
 ok     3	pre-vote.test_promote_no_quorum
 # Ran 3 tests in 6.994 seconds, 2 succeeded, 1 failed

This is the moment when one of the followers disconnects from
the leader and expects its `box.info.election.leader_idle` to grow.

It wasn't taken into account that this disconnect might lead to leader
resign due to fencing, and then a new leader would emerge and
`leader_idle` would still be small.

IOW, the leader starts with fencing turned off, and only resumes
fencing, once it has connected to a quorum of nodes (one replica in this
test). If the replica that we just connected happens to be the one we
disconnect in the test, the leader might fence, if it hasn't yet
connected to the other replica, because it immediately loses a quorum of
healthy connections right after gaining it for the first time.

Fix this by waiting until everyone follows everyone before each test
case.

The test, of course, could be fixed by turning fencing off, but this
might hide any possible future problems with fencing.

Follow-up #6654
Follow-up #6661

NO_CHANGELOG=test fix
NO_DOC=test fix

After scanning disk, the Vinyl read iterator checks if it should restore
the iterator over the active memory tree, because new tuples could have
been inserted into it while we yielded reading disk. We assume that
existing tuples can't be deleted from the memory tree, but that's not
always true - a tuple may actually be deleted by rollback after a failed
WAL write. Let's reevaluate all scanned sources and reposition the read
iterator to the next statement if this happens.

Initially, the issue was fixed by commit 83462a5c ("vinyl: restart
read iterator in case L0 is changed"), but it introduced a performance
degradation and was reverted (see #5700).

NO_DOC=bug fix
NO_TEST=already there
NO_CHANGELOG=already there

The Vinyl read iterator, which is used for serving range select
requests, works as follows:

 1. Scan in-memory sources. If found an exact match or a chain in
    the cache, return it.
 2. If not found, scan disk sources. This operation may yield.
 3. If any new data was inserted into the active memory tree, go to
    step 1, effectively restarting the iteration from the same key.

Apparently, such an algorithm doesn't guarantee any progress of a read
operation at all - when we yield reading disk on step 2 after a restart,
even newer data may be inserted into the active memory tree, forcing us
to restart again. In other words, in presence of an intensive write
workload, read ops rate may drop down to literally 0.

It hasn't always been like so. Before commit 83462a5c ("vinyl:
restart read iterator in case L0 is changed"), we only restored the
memory tree iterator after a yield, without restarting the whole
procedure. This makes sense, because only memory tree may change after
a yield so there's no point in rescanning other sources, including
disk. By restarting iteration after a yield, the above-mentioned commit
fixed bug #3395: initially we assumed that statements may never be
deleted from a memory tree while actually they can be deleted by
rollback after a failed WAL write.

Let's revert this commit to fix the performance degradation. We will
re-fix bug #3395 in the next commit.

Closes #5700

NO_DOC=bug fix
NO_TEST=should be checked by performance tests

* Avoid conflict between 64 bit lightuserdata and ITERN key.
* Reorganize lightuserdata interning code.
* test: fix path storage for non-concatable objects
* ARM64: Fix assembly of HREFK.
* FFI/ARM64: Fix pass-by-value struct calling conventions.
* test: set DYLD_LIBRARY_PATH environment variable
* x64/LJ_GC64: Fix fallback case of asm_fuseloadk64().
* FFI: Handle zero-fill of struct-of-NYI.
* Fix interaction between profiler hooks and finalizers.
* Flush and close output file after profiling run.
* Fix debug.debug() for non-string errors.
* Fix write barrier for lua_setupvalue() and debug.setupvalue().
* Fix FOLD rule for strength reduction of widening.
* Fix bytecode dump unpatching.
* Fix tonumber("-0") in dual-number mode.
* Fix tonumber("-0").
* Give expected results for negative non-base-10 numbers in tonumber().
* Add missing LJ_MAX_JSLOTS check.
* Add stricter check for print() vs. tostring() shortcut.

Closes #6548
Fixes #4614
Fixes #4630
Fixes #5885
Fixes tarantool/tarantool-qa#234
Fixes tarantool/tarantool-qa#235
Follows up #2712

NO_DOC=LuaJIT submodule bump
NO_TEST=LuaJIT submodule bump

Normally, there shouldn't be any upserts on disk if the space has
secondary indexes, because we can't generate an upsert without a lookup
in the primary index hence we convert upserts to replace+delete in this
case. The deferred delete optimization only makes sense if the space has
secondary indexes. So we ignore upserts while generating deferred
deletes, see vy_write_iterator_deferred_delete.

There's an exception to this rule: a secondary index could be created
after some upserts were used on the space. In this case, because of the
deferred delete optimization, we may never generate deletes for some
tuples for the secondary index, as demonstrated in #3638.

We could fix this issue by properly handle upserts in the write iterator
while generating deferred delete, but this wouldn't be easy, because in
case of a minor compaction there may be no replace/insert to apply the
upsert to so we'd have to keep intermediate upserts even if there is a
newer delete statement. Since this situation is rare (happens only once
in a space life time), it doesn't look like we should complicate the
write iterator to fix it.

Another way to fix it is to force major compaction of the primary index
after a secondary index is created. This looks doable, but it could slow
down creation of secondary indexes. Let's instead simply disable the
deferred delete optimization if the primary index has upsert statements.
This way the optimization will be enabled sooner or later, when the
primary index major compaction occurs. After all, it's just an
optimization and it can be disabled for other reasons (e.g. if the space
has on_replace triggers).

Closes #3638

NO_DOC=bug fix

* doc: add allocators hierarchy diagram
* build: fix CMake warning
* small: fix compilation on macOS 12

NO_DOC=small submodule bump
NO_TEST=small submodule bump
NO_CHANGELOG=small submodule bump

Asserts are disabled in the Release build, that leads to:

$ cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_FLAGS=-Werror
$ make

[ 43%] Building C object src/lib/bitset/CMakeFiles/bitset.dir/bitset.c.o
src/lib/bitset/bitset.c:169:9: error: variable 'cardinality_check' set but not used [-Werror,-Wunused-but-set-variable]
        size_t cardinality_check = 0;
               ^

NO_DOC=build fix
NO_TEST=build fix
NO_CHANGELOG=build fix

This will fix compilation on recent Archlinux. The issue is this distro
installs libbpf in base configuration and nghttp2 1.46.0 tries to
compile eBPF code if this library is present and failed if compiler is
gcc.

Closes #7292

NO_DOC=nghttp2 submodule bump
NO_TEST=nghttp2 submodule bump

Now fiber.top() does not use x86-specific instructions, so it can be
enabled for ARM.

Closes #4573

NO_TEST=<Tested in test/app/fiber.test.lua>
NO_DOC=<x86 or ARM are not mentioned in the fiber.top doc>

It doesn't make sense after switching from RDTSCP to
clock_gettime(CLOCK_MONOTONIC).

Part of #5869

@TarantoolBot document
Title: fiber: get rid of cpu_misses in fiber.top()
Since: 2.11

Remove any mentions of `cpu_misses` in `fiber.top()` description.

clock_gettime(CLOCK_MONOTONIC) is implemented via the RDTSCP instruction
on x86 an has the following advantages over the raw instruction:

* It checks for RDTSCP availability in CPUID.
  If RDTSCP is not supported, it switches to RDTSC.
* Linux guarantee that clock is monotonic, hence, the CPU miss
  detection is not needed.
* It works on ARM.

As for disadvantage, this function is about 2x slower compared to a
single RDTSCP instruction. Performance degradation measured by the
fiber switch benchmark [1] is about 3-7% for num_fibers == 10-1000.

Closes #5869

[1] https://github.com/tarantool/tarantool/issues/2694#issuecomment-546381304

NO_DOC=bugfix
NO_TEST=<Tested in test/app/fiber.test.lua>

Use this wrapper to simplify the code.

Part of #5869

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

clock_gettime() returns 0 for success, or -1 for failure.
Add missed checks for the return value.

Part of #5869

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

These 3 modules are low hanging fruits which right now can be
freed at return from main() without any effort.

There are still a lot of other modules whose freeing is not that
easy. A few hard to untangle knots, and there are more:

- Session, credentials, iproto, and fibers are tied together via
  the latter. Each fiber potentially has a session, its current
  credentials object. Each iproto connection has a session and a
  file descriptor which is stored in the session too.

  The possible solution would be to walk all the fibers and
  destroy them before proceeding to destroy everything else.

- Tuples depend on memtx, and Lua depends on tuples. Because there
  are tuples allocated on memtx->arena. Hence destruction of memtx
  and its arena makes the tuples still stored in Lua invalid.

  It seems Lua should be destroyed first, not last. It would free
  all the refs which might be kept at objects in C in the other
  modules.

- IProto connections leak when iproto is destroyed. They are not
  freed and their descriptors are not closed properly. That
  requires additional preparatory work to destroy them correctly
  on iproto module deconstruction.

Given amount of work, it should be done as a big separate ticket.

Follow up #7259

NO_CHANGELOG=Not a visible change
NO_DOC=Not a visible change
NO_TEST=Not a visible change

main() used to skip most of modules destruction in
tarantool_free(). That got ASAN complaining on clang-13 about a
leak of a fiber on_stop trigger which was allocated in Lua.

The patch makes fiber_free() called for the main cord. It destroys
and frees all the fibers together with their on_stop triggers.

Closes #7259

NO_CHANGELOG=Not a visible change
NO_DOC=Not a visible change
NO_TEST=Not a visible change

Before this patch struct tuple had two boolean bit fields: is_dirty and
has_uploaded_refs. It is worth mentioning that sizeof(boolean) is
implementation depended. However, in code it is assumed to be 1 byte
(there's static assertion restricting the whole struct tuple size by 10
bytes). So strictly speaking it may lead to the compilation error on
some non-conventional system. Secondly, bit fields anyway consume at
least one size of type (i.e. there's no space benefits in using two
uint8_t bit fields - they anyway occupy 1 byte in total). There are
several known pitfalls concerning bit fields:
 - Bit field's memory layout is implementation dependent;
 - sizeof() can't be applied to such members;
 - Complier may raise unexpected side effects
   (https://lwn.net/Articles/478657/).

Finally, in our code base as a rule we use explicit masks:
txn flags, vy stmt flags, sql flags, fiber flags.

So, let's replace bit fields in struct tuple with single member called
`flags` and several enum values corresponding to masks (to be more
precise - bit positions in tuple flags).

NO_DOC=<Refactoring>
NO_CHANGELOG=<Refactoring>
NO_TEST=<Refactoring>

We did not retain correctly `hour` attribute if modified
via `:set` method attributes `min`, `sec` or `nsec`.

```
tarantool> a = dt.parse '2022-05-05T00:00:00'

tarantool> a:set{min = 0, sec = 0, nsec = 0}
--
- 2022-05-05T12:00:00Z
...
```

Closes #7298

NO_DOC=bugfix

If vy_point_lookup called by vy_sauash_process yields (doing disk read),
a dump may be triggered bumping the L0 generation counter, in which case
we would insert a statement to a sealed vy_mem, as explained in #5080.
Let's check the generation counter and rotate the active vy_mem if
necessary after vy_point_lookup to avoid that.

Closes #5080

NO_DOC=bug fix
NO_TEST=complicated, need stress/perf test to catch bugs like this

We often call vy_lsm_rotate_mem_if_required if its generation or schema
version is older than the current one. Let's add a helper function for
that.

Needed for #5080

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

The optimization is mostly useless, because it only works if there's no
data on disk. As explained in #5080, it contains a potential bug: if L0
dump is triggered between 'prepare' and 'commit', it will insert a
statement to a sealed vy_mem. Let's drop it.

Part of #5080

NO_DOC=bug fix
NO_CHANGELOG=later

gh_6634_different_log_on_tuple_new_and_free_test.lua verifies that
proper debug message gets into logs for tuple_new() and tuple_delete():
occasionally tuple_delete() printed wrong tuple address. However, still
there are two debug logs: one in tuple_delete() and another one in
memtx_tuple_delete(). So to avoid any possible confusions let's fix
regular expression to find proper log so that now it definitely finds
memtx_tuple_delete().

NO_CHANGELOG=<Test fix>
NO_DOC=<Test fix>