Even though this patch had no user-visible difference, better keep the code
in psqlscan.l sync with the backend lexer. And of course it's nice to shrink
the psql binary, too. Ecpg's version of the lexer doesn't have the error
rule, it doesn't try to avoid backing up, so it doesn't need to be modified.

As reminded by Tom Lane

Fully update git head, and update back branches in ./COPYRIGHT and
legal.sgml files.

Per discussion on-hackers. psql is converted to use the new code.

Follows a suggestion from Heikki Linnakangas.

client encoding and the client encoding is not *safe* one. Such an
example is, file encoding is UTF-8 and client encoding SJIS. Patch
contributed by Jiang Guiqing.

We had a number of variants on the theme of "malloc or die", with the
majority named like "pg_malloc", but by no means all.  Standardize on the
names pg_malloc, pg_malloc0, pg_realloc, pg_strdup.  Get rid of pg_calloc
entirely in favor of using pg_malloc0.

This is an essentially cosmetic change, so no back-patch.  (I did find
a couple of places where psql and pg_dump were using plain malloc or
strdup instead of the pg_ versions, but they don't look significant
enough to bother back-patching.)

For those variables only used when asserts are enabled, use a new
macro PG_USED_FOR_ASSERTS_ONLY, which expands to
__attribute__((unused)) when asserts are not enabled.

Still an exercise in satisfying pedants.

These changes allow backtick command evaluation and psql variable
interpolation to happen on substrings of a single meta-command argument.
Formerly, no such evaluations happened at all if the backtick or colon
wasn't the first character of the argument, and we considered an argument
completed as soon as we'd processed one backtick, variable reference, or
quoted substring.  A string like 'FOO'BAR was thus taken as two arguments
not one, not exactly what one would expect.  In the new coding, an argument
is considered terminated only by unquoted whitespace or backslash.

Also, clean up a bunch of omissions, infelicities and outright errors in
the psql documentation of variables and metacommand argument syntax.

As in the backend, the implementation actually accepts any non-ASCII
character, but we only document that you can use letters.

Per previous experimentation, backtracking slows down lexing performance
significantly (by about a third).  It's usually pretty easy to avoid, just
need to have rules that accept an incomplete construct and do whatever the
lexer would have done otherwise.

The backtracking was introduced by the patch that added quoted variable
substitution.  Back-patch to 9.0 where that was added.

This is recommended in the flex manual, and there seems no good reason
not to use it everywhere.

This warning is new in gcc 4.6 and part of -Wall.  This patch cleans
up most of the noise, but there are some still warnings that are
trickier to remove.

Original patch failed to include new exclusive states in a switch that
needed to include them; and also was guilty of very fuzzy thinking
about how to handle error cases.  Per bug #5729 from Alan Choi.

"val AS name" to "name := val", as per recent discussion.

This patch catches everything in the original named-parameters patch,
but I'm not certain that no other dependencies snuck in later (grepping
the source tree for all uses of AS soon proved unworkable).

In passing I note that we've dropped the ball at least once on keeping
ecpg's lexer (as opposed to parser) in sync with the backend.  It would
be a good idea to go through all of pgc.l and see if it's in sync now.
I didn't attempt that at the moment.

refers to itself (directly or indirectly).  Instead, print a message when
recursion is detected, and don't expand the repeated reference.  Per bug
#5448 from Francis Markham.

Back-patch to 8.0.  Although the issue exists in 7.4 as well, it seems
impractical to fix there because of the lack of any state stack that
could be used to track active expansions.

Loosely based on a patch by Pavel Stehule.

directly.  This was a lot of trouble, but should be worth it in terms of
not having to keep the plpgsql lexer in step with core anymore.  In addition
the handling of keywords is significantly better-structured, allowing us to
de-reserve a number of words that plpgsql formerly treated as reserved.

Marko Kreen, Tom Lane

results (ie, an empty "broken" buffer) if memory overrun occurs anywhere
along the way to filling the buffer.  The previous coding would just silently
discard portions of the intended buffer contents, as exhibited in trouble
report from Sam Mason.  Also, tweak psql's main loop to correctly detect
and report such overruns.  There's probably much more that should be done
in this line, but this is a start.

began to realize that the input() function isn't used and printed warnings.

This has been the only documented and encouraged syntax for a long time, and
with extension facilities such as aliases being proposed, it is a good time to
clean up the legacy syntax a bit.

Author: Bernd Helmle <mailings@oopsware.de>

renumbering of encoding IDs done between 8.2 and 8.3 turns out to break 8.2
initdb and psql if they are run with an 8.3beta1 libpq.so.  For the moment
we can rearrange the order of enum pg_enc to keep the same number for
everything except PG_JOHAB, which isn't a problem since there are no direct
references to it in the 8.2 programs anyway.  (This does force initdb
unfortunately.)

Going forward, we want to fix things so that encoding IDs can be changed
without an ABI break, and this commit includes the changes needed to allow
libpq's encoding IDs to be treated as fully independent of the backend's.
The main issue is that libpq clients should not include pg_wchar.h or
otherwise assume they know the specific values of libpq's encoding IDs,
since they might encounter version skew between pg_wchar.h and the libpq.so
they are using.  To fix, have libpq officially export functions needed for
encoding name<=>ID conversion and validity checking; it was doing this
anyway unofficially.

It's still the case that we can't renumber backend encoding IDs until the
next bump in libpq's major version number, since doing so will break the
8.2-era client programs.  However the code is now prepared to avoid this
type of problem in future.

Note that initdb is no longer a libpq client: we just pull in the two
source files we need directly.  The patch also fixes a few places that
were being sloppy about checking for an unrecognized encoding name.

back-stamped for this.

NOT the thing to use here.

throw warnings for 100%-SQL-standard constructs, clean up some minor
infelicities, try to un-break ecpg to the best of my ability.  (It's not clear
how ecpg is going to find out the setting of standard_conforming_strings,
though.)  I think pg_dump still needs work, too.

Kevin Grittner

with main, avoid using a SQL-defined SQLSTATE for what is most definitely
not a SQL-compatible error condition, fix documentation omissions,
adhere to message style guidelines, don't use two GUC_REPORT variables
when one is sufficient.  Nothing done about pg_dump issues.

broke it.  Maybe we do need an automated check ...