It is a dictionary-like struct which stores keys with binary data
values. The values are supposed to be arbitrary MessagePack blobs:
number, string, bool, UUID, array, map, anything.

The payload is an array inside instead of a hash table because
number of keys will be <= 3 in all cases. And even when it will be
public, it is very unlikely it will be bigger.

Object of error_payload in a future patch will be stored in struct
error and will allow to extend it dynamically with more members.

This in turn is needed to extend ER_READONLY error with more
details about why it happened.

Part of #5568
Part of #4907

libuuid used to be a separate library since
de11d68a ("CMake: refactor
dependencies of internal libraries").

Unclear what was it done for. The commit says "fir unit tests".
But they perfectly fine can depend on libcore like many of them
do already.

Because of libuuid being a separate library, libcore can't use
tt_uuid, because that would be a cyclic dependency. And that won't
allow to introduce tt_uuid-dependent API in a next patch.

Hence libuuid is merged into libcore.

Needed for #5568

And from diag_add(). This will be helpful not to bother with
box_error_last() and diag_last_error(diag_get()) in the future
patch. It will change some attributes of a just created
ER_READONLY error to add more details.

Part of #5568

Watcher unit test linked with libbox and included
core_test_utils.c. Both contain cord_on_yield() symbol.

It is defined as a stub in core_test_utils and checks being inside
of GC in libbox.

Somehow it managed to link all this time just fine. And moreover
the linker selected the correct symbol - the one from
core_test_utils.

But while making another patch (not submitted yet), some other
unit test was changed a bit and the watcher unit test link stage
started failing with 'cord_on_yield()' duplicate symbol.

The patch drops core_test_utils from the test and makes it work
with libbox correctly. To support that the test now needs to
initialize the global Lua state.

Actualize changelog based on GitHub release pages changelogs. Some
entries were skipped since they are not relevant to modern packages.
Versions 1.8.1 and 2.0.4 changelogs were merged to 2.1.1 changelog.

Closes #6397

Actualize changelog based on GitHub release pages changelogs. Some
entries were skipped since they are not relevant to modern packages.
Versions 1.8.1 and 2.0.4 changelogs were merged to 2.1.1 changelog.

Part of #6397

This patch extends the 'integration.yml' workflow and adds a new
workflow call for running tests to verify integration between tarantool
and the expiration module.

Part of #5265
Part of #6056
Closes #6528

This commit fixes the following failure:

```
[028] --- wal_off/snapshot_stress.result	Fri Jun  5 06:49:36 2020
[028] +++ wal_off/snapshot_stress.reject	Fri Oct 16 13:48:23 2020
[028] @@ -375,7 +375,7 @@
[028]  ...
[028]  snaps_find_status;
[028]  ---
[028] -- snaps found
[028] +- where are my snapshots?
[028]  ...
[028]  snapshot_check_failed = false
[028]  while #snaps > initial_snap_count do
[028]
```

It happens, because the fiber making snapshots is started after worker
fibers and it works until all worker fibers are done so it might occur
that it doesn't make any snapshots. Fix this by replacing the while-loop
with a repeat-loop, thus ensuring that the worker fiber makes at least
one snapshot.

Closes #5431

Just need to replace scoped guards with labels and add struct keyword to
the sockaddr types.

While we are at it, replace malloc with xmalloc in coio_fill_addrinfo -
we don't check if the returned valued is NULL anyway.

There are just a few places outside coio.cc and coio_buf.h where these
functions are used directly (most users use helpers from coio_buf.h or
xrow_io.h): popen, console, applier.

This is a step towards conversion of coio to C.

This commit makes coio_stat_stat_timeout, coio_waitpid, and
coio_service_start exception-free. None of the functions is used
anywhere in the code except for tests.

This is a step towards conversion of coio to C.

Note, the only place where coio_connect is used is applier_connect,
while coio_accept isn't used anywhere.

This is needed to convert the net.box state machine to C.

So that users that don't have an uri at hand can use it.

This is needed to convert the net.box state machine to C.

Closes #3174

@TarantoolBot document
Title: Field type ANY in SQL

Properties of type ANY in SQL:
1) typeof() with an argument of type ANY returns "any";
2) any value of any type can be implicitly and explicitly cast to the ANY type;
3) a value of type ANY cannot be implicitly cast to any other type;
4) a value of type ANY cannot participate in arithmetic, bitwise, comparison,
   and concationation operations.

After this patch, the built-in SQL function implementation definitions
will use field_type_MAX to indicate that they accept values of any type,
instead of FIELD_TYPE_ANY.

Part of #3174

Prior to this patch, in some cases a struct Expr value with an opcode
TK_INTEGER could have field type ANY. This patch sets such values to the
INTEGER field type.

Part of #3174

This patch extends the 'integration.yml' workflow and adds a new
workflow call for running tests to verify integration between tarantool
and the tarantool-php/queue connector.

Part of #5265
Part of #6056
Closes #6595

This patch forces SQL built-in function implementations to accept
'const struct Mem *' instead of just 'struct Mem *'.

Needed for #4145

This patch removes the MEM_Term flag, because after changes in the SQL
built-in functions, this flag is no longer used.

Needed for #4145

This patch removes the MEM_Dyn flag, because after changes in the SQL
built-in functions, this flag is no longer used.

Needed for #4145

Some of the code is no longer used after changes in the SQL built-in
functions. This patch removes part of the unused code.

Needed for #4145

Part of #4145

Part of #4145

Part of #4145

Part of #4145

This patch refactors UUID() function. Also, UUID(NULL) now returns NULL.

Part of #4145

Part of #4145

Part of #4145

Part of #4145

Part of #4145

This patch refactors RANDOMBLOB() function. Also, RANDOMBLOB(0) now
returns empty string.

part of #4145

Part of #4145

Part of #4145

Part of #4145

Part of #4145

Part of #4145

The CHAR() function now uses the ICU macro to get characters.

Part of #4145

Part of #4145

This patch makes SUBSTR() work according to ANSI rules for SUBSTRING()
function. Also, SUBSTR() can now work correctly with large INTEGER
values. The SUBSTR() syntax has not changed.

Part of #4145

@TarantoolBot document
Title: SUBSTR() function

SUBSTR() now works according to the ANSI rules for SUBSTRING().

Rules for SUBSTR() with 2 arguments:
1) let the first argument be VALUE, and the second argument be START;
2) VALUE should be STRING or VARBINARY, START should be INTEGER;
3) if any of arguments is NULL, NULL is returned;
4) let POS be MAX(START - 1, 0), END be length of the VALUE;
5) if POS >= END, the result is empty string;
6) if POS < END, the result will be substring of VALUE, starting from
   the position POS to the position END.

Rules for SUBSTR() with 3 arguments:
1) let the first argument be VALUE, the second argument be START, and
   the third argument be LENGTH;
2) VALUE should be STRING or VARBINARY, START and LENGTH should be
   INTEGERs;
3) if any of arguments is NULL, NULL is returned;
4) if LENGTH < 0, an error is thrown;
5) let POS be MAX(START - 1, 0), END be START + LENGTH - 1;
6) if POS >= END, the result is empty string;
7) if POS < END, the result will be substring of VALUE, starting from
   the position POS to the position END.