In p_isdigit and other character class test functions generated by the
p_iswhat macro, the code path for non-C locales with multibyte encodings
contained a bogus pointer cast that would accidentally fail to malfunction
if types wchar_t and wint_t have the same width.  Apparently that is true
on most platforms, but not on recent Cygwin releases.  Remove the cast,
as it seems completely unnecessary (I think it arose from a false analogy
to the need to cast to unsigned char when dealing with the <ctype.h>
functions).  Per bug #8970 from Marco Atzeri.

In the same functions, the code path for C locale with a multibyte encoding
simply ANDed each wide character with 0xFF before passing it to the
corresponding <ctype.h> function.  This could result in false positive
answers for some non-ASCII characters, so use a range test instead.
Noted by me while investigating Marco's complaint.

Also, remove some useless though not actually buggy maskings and casts
in the hand-coded p_isalnum and p_isalpha functions, which evidently
got tested a bit more carefully than the macro-generated functions.

WalSndKill was doing things exactly backwards: it should first clear
MyWalSnd (to stop signal handlers from touching MyWalSnd->latch),
then disown the latch, and only then mark the WalSnd struct unused by
clearing its pid field.

Also, WalRcvSigUsr1Handler and worker_spi_sighup failed to preserve
errno, which is surely a requirement for any signal handler.

Per discussion of recent buildfarm failures.  Back-patch as far
as the relevant code exists.

The preferred method is to use "cc -shared", and this allows binaries
to be rebased if required, unlike dllwrap.

Backpatch to 9.0 where we have buildfarm coverage.

There are still some issues with Cygwin, especially modern Cygwin, but
this helps us get closer to good support.

Marco Atzeri.

This has long been done by the MSVC build system, and has caused
confusion in the past when programs like psql have failed to start
because they can't find the DLL. If it's in the same directory as it now
will be they will find it.

Backpatch to all live branches.

Previously an input array string that started with a single-element
array dimension would then later accept a multi-dimensional segment.

BACKWARD INCOMPATIBILITY

Replication slots are a crash-safe data structure which can be created
on either a master or a standby to prevent premature removal of
write-ahead log segments needed by a standby, as well as (with
hot_standby_feedback=on) pruning of tuples whose removal would cause
replication conflicts.  Slots have some advantages over existing
techniques, as explained in the documentation.

In a few places, we refer to the type of replication slots introduced
by this patch as "physical" slots, because forthcoming patches for
logical decoding will also have slots, but with somewhat different
properties.

Andres Freund and Robert Haas

Mentioned in substring() and regexp_replace() sections.

per report from Josh Kupershmidt

Evidence from buildfarm member crake suggests that the new test_shm_mq
module is routinely crashing the server due to the arrival of a SIGUSR1
after the shared memory segment has been unmapped.  Although processes
using the new dynamic background worker facilities are more likely to
receive a SIGUSR1 around this time, the problem is also possible on older
branches, so I'm back-patching the parts of this change that apply to
older branches as far as they apply.

It's already generally the case that code checks whether these pointers
are NULL before deferencing them, so the important thing is mostly to
make sure that they do get set to NULL before they become invalid.  But
in master, there's one case in procsignal_sigusr1_handler that lacks a
NULL guard, so add that.

Patch by me; review by Tom Lane.

Takayuki Tsunakawa

Report from Jozef Mlich using Coverity

Backpatch to 9.3

Adjusted patch from Ian Lawrence Barwick

Commit 820f08ca claimed to make the server
and libpq handle SSL protocol versions identically, but actually the server
was still accepting SSL v3 protocol while libpq wasn't.  Per discussion,
SSL v3 is obsolete, and there's no good reason to continue to accept it.
So make the code really equivalent on both sides.  The behavior now is
that we use the highest mutually-supported TLS protocol version.

Marko Kreen, some comment-smithing by me

Dean Rasheed

Michael Paquier

Suggested by David Tonhofer

Document that FOR UPDATE/SHARE are incompatible with GROUP BY, DISTINCT,
HAVING and window functions.

Michael Paquier

Report form Antonin Houska

Allows typedefs to be specified on the command line, per request from
Andrew.

Add new entab options to process only C comment whitespace after
periods, and to protect leading whitespace.

Per gripe from hubert depesz lubaczewski.

Also improve examples for this and json_array_elements so they match the
example results.

The buildfarm says commit 58274728 doesn't
work so well on Windows.  This is because the encoding part of Windows
locale names can be just a code page number, eg "1252", which we don't
consider to be a valid encoding name.  Add a check to accept encoding
parts that are case-insensitively string equal; this at least ensures
that the new code doesn't reject any cases that the old code allowed.

This requires a new version of pg_bsd_indent, version 1.3, to be
downloaded.

Even though the server tries to canonicalize stored locale names, the
platform often doesn't cooperate, so it's entirely possible that one DB
thinks its locale is, say, "en_US.UTF-8" while the other has "en_US.utf8".
Rather than failing, we should try to allow this where it's clearly OK.

There is already pretty robust encoding lookup in encnames.c, so make
use of that to compare the encoding parts of the names.  The locale
identifier parts are just compared case-insensitively, which we were
already doing.  The major problem known to exist in the field is variant
encoding-name spellings, so hopefully this will be Good Enough.  If not,
we can try being even laxer.

Pavel Raiskup, reviewed by Rushabh Lathia

Thinko in error report (and a typo in the message text, too).  We're
failing anyway, but it would be good to print something useful first.
Noted while reviewing a patch to make pg_upgrade's locale code laxer.

Vik Fearing, reviewed by Pavel Stehule and myself

When pulling a "postponed" qual from a LATERAL subquery up into the quals
of an outer join, we must make sure that the postponed qual is included
in those seen by make_outerjoininfo().  Otherwise we might compute a
too-small min_lefthand or min_righthand for the outer join, leading to
"JOIN qualification cannot refer to other relations" failures from
distribute_qual_to_rels.  Subtler errors in the created plan seem possible,
too, if the extra qual would only affect join ordering constraints.

Per bug #9041 from David Leverton.  Back-patch to 9.3.

Backpatch to 9.3

Greg Smith

New checks include input, month/day/time internal adjustments, addition,
subtraction, multiplication, and negation.  Also adjust docs to
correctly specify interval size in bytes.

Report from Rok Kralj

Various places were supposing that errno could be expected to hold still
within an ereport() nest or similar contexts.  This isn't true necessarily,
though in some cases it accidentally failed to fail depending on how the
compiler chanced to order the subexpressions.  This class of thinko
explains recent reports of odd failures on clang-built versions, typically
missing or inappropriate HINT fields in messages.

Problem identified by Christian Kruse, who also submitted the patch this
commit is based on.  (I fixed a few issues in his patch and found a couple
of additional places with the same disease.)

Back-patch as appropriate to all supported branches.

They are in fact set in every case where they are needed, but the
compiler doesn't know that.

Per gripe from Tom Lane.

This doesn't work for prepared queries, but it's not too easy to get
the information in that case and there's some debate as to exactly
what the right thing to measure is, so just do this for now.

Andreas Karlsson, with slight doc changes by me.

This was a notable omission from the json functions added in 9.3 and
there have been numerous complaints about its absence.

Laurence Rowe.

We calculated the rounded-up size for the allocation, but then failed to
use the rounded-up value in the mmap() call. Oops.

Also, initialize allocsize, to silence warnings seen with some compilers,
as pointed out by Jeff Janes.