Editorconfig is a standard of defining indentation style and other
settings such as newline types for different file types in a project.

See https://editorconfig.org/

It is achieved by introducing a simple .editorconfig dotfile with
glob expressions and settings per fiile type. Editors then can read
this file and decide which indentation style they should use for a
given project file.

All binary struct *_request are stored in xrow.h/.c
together with their decoders. The only reason why
xrow_decode_sql was implemented in execute.c was a
dependency on struct sql_bind. Now xrow_decode_sql
and struct sql_request operate only by MessagePack and
some iproto constants and are moved to their true
home.

Follow up #3828

Before this patch bind parameters were decoded in
iproto thread in an attempt to save some TX thread
time. But they were stored in an array allocated on
iproto thread memory. Lack of iproto_msg destructor
lead to leak of this array.

This patch makes sql_request store only raw undecoded
MessagePack and moves decoding to TX thread where in
a single function the parameters are decoded, applied
and freed.

There were a couple of alternatives allowing to keep
decoding in iproto thread and to move even more
decoding there, for example, parameters from
IPROTO_UPDATE:

* decode on malloc and add a virtual destructor to
  struct iproto_msg;

* decode on malloc and add a virtual destructor to
  struct cmsg. By the way, it could allow to reuse
  this destructor for struct cbus_call_msg and
  struct relay_gc_msg.

The way how is it solved by this patch has been chosen
thanks to its simplicity.

Closes #3828

This reverts commit bc9e41e9.

This is one step forward to make sql_request store raw
MessagePack.

Part of #3828

sql_request is now decoded entirely in iproto thread
in iproto_msg_decode unlike other similar requests
like CALL or UPDATE which could be decoded in iproto
too.

But iproto thread pays for this optimization with a
leak - sql_request.bind array is allocated on iproto
thread region and never freed.

A fix is to decode, apply and free bind array in tx
thread in one place: tx_process_sql. For this
sql_request should look like other requests: do not
decode arrays, do not store sync, store fields as
raw MsgPack.

First step - remove sync.

Part of #3828

The value of box.cfg.replication_timeout should be the same on all
members of a cluster, otherwise replication may stop on timeout.
Since master.lua has box.cfg.replication_timeout set to 0.1, we should
use the same value in all replica scripts.

This fixes replication/wal_rw_stress test sporadic failure.

Closes #3885

FALLOC_FL_KEEP_SIZE flag has existed since fallocate() was first
introduced, but it was not defined in glibc headers for a while.
Define it manually if necessary.

Follow-up b9db91e1 ("xlog: fix fallocate vs read race").

posix_fallocate(), which is used for preallocating disk space for WAL
files, increases the file size and fills the allocated space with zeros.
The problem is a WAL file may be read by a relay thread at the same time
it is written to. We try to handle the zeroed space in xlog_cursor (see
xlog_cursor_next_tx()), however this turns out to be not enough, because
transactions are written not atomically so it may occur that a writer
writes half a transaction when a reader reads it. Without fallocate, the
reader would stop at EOF until the rest of the transaction is written,
but with fallocate it reads zeroes instead and thinks that the xlog file
is corrupted while actually it is not.

Fix this issue by using fallocate() with FALLOC_FL_KEEP_SIZE flag
instead of posix_fallocate(). With the flag fallocate() won't increase
the file size, it will only allocate disk space beyond EOF.

Closes #3883

VIEW can be created not only in form of AS SELECT but also in form of AS
VALUES (...). In the latter case space's view reference counters were
not incremented. Furthermore, if view came with sub-select, reference
counters of tables within sub-select were not updated as well. These
problems occurred due to simplified traverse over AST: only tables
within FROM clause were accounted. This patch fixes them introducing
complete pass over AST using walker.

Closes #3815

xlog/panic_on_broken_lsn.test.lua fails on
box.schema.space.create('test') after
xlog/checkpoint_threshold.test.lua.

Follow-up db8c7aa3 ("wal: trigger checkpoint if there are
too many WALs").

Add test to check result for indexed char in sub subquery.

Closes #3616

Fix an ability to describe CHAR without specifying the
length as it is allowed by standard. It was
accidentally broken by this commit:
7752cdfd

Length is just an integer, part of a type, not a
whole type.

If VIEW contains constant fields (e.g. CREATE VIEW v AS SELECT 1, 'k';)
it uses string representation of literal as a field name. In the example
above it would be '1' and 'k'. However, if VIEW is created using AS VALUES
syntax, then expressions representing constant literals lack of names
(since span-expression is not assigned in this case).
Lets generate names for all fields which lack names for VIEW.

Closes #3849

Disabled LTO builds, tarballs and packages building on short-term
branches.

Removed 'allow_failures' on coverage / debug build.

Replaced matrix expansion with the list of jobs (because Travis-CI
documentation says it does not support condition jobs with matrix
expansion).

Fixes #3755.

Allow exploring rocks documentation locally with
`tarantoolctl rocks doc ...`

In context of #3753

Otherwise it is hard to debug code throwing exceptions.
fio.pathjoin() was just one example among many.

@locker:
 - slightly edit error messages
 - filter out line numbers from error messages in the test

Closes #3580

To wait for a thread writing a snap file memtx_engine_wait_checkpoint()
uses cord_cojoin(), which doesn't tolerate spurious wakeups. Hence we
must not wake up the checkpoint fiber after reconfiguring the checkpoint
interval if it's currently making a checkpoint.

Fixes 4c04808a ("Rewrite checkpoint daemon in C").

Closes #3878

There are a few warning messages that can easily flood the log, making
it more difficult to figure out what causes the problem. Those are
 - too long WAL write
 - waited for ... bytes of vinyl memory quota for too long
 - get/select(...) => ... took too long
 - readahead limit is reached
 - net_msg_max limit is reached

Actually, it's pointless to print each and every of them, because all
messages of the same kind are similar and don't convey any additional
information.

So this patch limits the rate at which those messages may be printed.
To achieve that, it introduces say_ratelimited() helper, which works
exactly like say() except it does nothing if too many messages of
the same kind have already been printed in the last few seconds.
The implementation is trivial - say_ratelimited() defines a static
ratelimit state variable at its call site (it's a macro) and checks it
before logging anything. If the ratelimit state says that an event may
be emitted, it will log the message, otherwise it will skip it and
eventually print the total number of skipped messages instead.

The rate limit is set to 10 messages per 5 seconds for each kind of
a warning message enumerated above.

Here's how it looks in the log:

2018-12-11 18:07:21.830 [30404] iproto iproto.cc:524 W> stopping input on connection fd 15, aka 127.0.0.1:12345, peer of 127.0.0.1:59212, readahead limit is reached
2018-12-11 18:07:21.831 [30404] iproto iproto.cc:524 W> stopping input on connection fd 15, aka 127.0.0.1:12345, peer of 127.0.0.1:59212, readahead limit is reached
2018-12-11 18:07:21.831 [30404] iproto iproto.cc:524 W> stopping input on connection fd 15, aka 127.0.0.1:12345, peer of 127.0.0.1:59212, readahead limit is reached
2018-12-11 18:07:21.831 [30404] iproto iproto.cc:524 W> stopping input on connection fd 15, aka 127.0.0.1:12345, peer of 127.0.0.1:59212, readahead limit is reached
2018-12-11 18:07:21.831 [30404] iproto iproto.cc:524 W> stopping input on connection fd 15, aka 127.0.0.1:12345, peer of 127.0.0.1:59212, readahead limit is reached
2018-12-11 18:07:21.832 [30404] iproto iproto.cc:524 W> stopping input on connection fd 15, aka 127.0.0.1:12345, peer of 127.0.0.1:59212, readahead limit is reached
2018-12-11 18:07:21.832 [30404] iproto iproto.cc:524 W> stopping input on connection fd 15, aka 127.0.0.1:12345, peer of 127.0.0.1:59212, readahead limit is reached
2018-12-11 18:07:21.832 [30404] iproto iproto.cc:524 W> stopping input on connection fd 15, aka 127.0.0.1:12345, peer of 127.0.0.1:59212, readahead limit is reached
2018-12-11 18:07:21.832 [30404] iproto iproto.cc:524 W> stopping input on connection fd 15, aka 127.0.0.1:12345, peer of 127.0.0.1:59212, readahead limit is reached
2018-12-11 18:07:21.832 [30404] iproto iproto.cc:524 W> stopping input on connection fd 15, aka 127.0.0.1:12345, peer of 127.0.0.1:59212, readahead limit is reached
2018-12-11 18:07:26.851 [30404] iproto iproto.cc:524 W> 9635 messages suppressed

Closes #2218

We will use it to limit the rate of log messages.

Needed for #2218

As described by Vlad in gh-3875 it's incorrect to rely on the state
of the diagnostics area to determine whether there was a EINTR
style error on sio or not. The area may be dirty with some previous
error.

Follow-up 07191842 ("gc: run garbage collection in background").

Closes #3855

Before the patch on_disconnect triggers were called
only after last outstanding request had finished. It
was enough for most goals. But after box.session.push
was implemented, it appeared that it is impossible to
return an error from push() if a connection is closed.

Tx session just does not know that a connection is
already closed. The patch splits destroy and
disconnect phases of an iproto connection lifecycle.
Disconnect calls on_disconnect triggers and resets
iproto socket fd. Destroy frees resources.

Needed for #3859

Disconnect cmsg is a message that is used by iproto
thread to notify tx thread that a connection is dead
and has no outstanding requests. That is its
tx-related resourses are freed and the connection is
deleted.

But the text above is clear definition of destroy. The
patch harmonizes cmsg name and its puprose.

Secondly, the patch is motivated by #3859 which
requires separate disconnect and destroy phases.

Needed for #3859

As we going to work with format fields in a unified way, we should use
the json tree class for managing top-level tuple format fields.

@locker: comments and style fixes.

Needed for #1012

Needed for #3234

coio_accept() calls evio_setsockopt_client, which
throws an exception and just accepted socket leaks.
Yes, server socket is protected, but not new client
socket.

The bug existed even before exceptions are removed
from evio.

Remove them to be able to convert evio to C - final
step to make it usable in SWIM.

Needed for #3234

coio_service_on_accept is called by evio by an
on_accept pointer. If evio obtains not zero from
on_accept pointer, it closes accepted socket. But
coio_service_on_accept closes it too, when fiber_new
fails. It is double close.

Note that the bug existed even when on_accept was able
to throw.

Evio is going to be C, because it is needed in SWIM to
1) support UNIX sockets in future;
2) do not care about setting SocketError directly. It
is not possible via bare sio, because sio_bind ignores
EADDRINUSE.

A first step to make evio C - eliminate exceptions
from its callbacks available to other modules. The
only callback it has - on_accept.

Needed for #3234

Needed for #3234

Propagate exceptions up to the caller. Function sio_writev().

In scope of #3234

Propagate exceptions up to the caller. Functions sio_read(),
sio_write().

Add an assert for sio_write() with zero bytes.

In scope of #3234

Propagate exceptions up to the caller. Functions sio_sendto(),
sio_recvfrom().

In scope of #3234

Propagate exceptions up to the caller.

In scope of #3234

Describe in module comments the principles of API construction
for sio.c. Add necessary comments. Add a helper function
which makes the code a little simpler.

In scope of gh-3234.

It is now suitable not only for handling JSON paths, but also for
building complex JSON structures.

Follow-up b56103f5 ("json: some renames").

Introduced json_path_validate routine to ensure user-defined
JSON path is valid. This will be required to raise an error if
an incorrect user-defined jason-path is detected.

Introduced json_path_cmp routine to compare JSON paths that may
have different representation.
Note that:
 - in case of paths that have same token-sequence prefix,
   the path having more tokens is assumed to be greater
 - both paths to compare must be valid

@locker: move json_path_validate to the object file (no need to
pollute the header with this cold routine).

Needed for #1012