xml_parse, all arising from the same sloppy usage of parse_xml_decl.
The original coding had that function returning its output string
parameters in the libxml context, which is long-lived, and all but one
of its callers neglected to free the strings afterwards.  The easiest
and most bulletproof fix is to return the strings in the local palloc
context instead, since that's short-lived.  This was only costing a
dozen or two bytes per function call, but that adds up fast if the
function is called repeatedly ...

Noted while poking at the more general problem of what to do with our
libxml memory allocation hooks.  Back-patch to 8.3, which has the
identical coding.

map_sql_value_to_xml_value() instead of directly through the data type output
function.  This is per SQL standard, and consistent with XMLELEMENT().

while converting to XML.  Bernd Helmle

not include postgres.h nor anything else it doesn't directly need.  Add
#includes to calling files as needed to compensate.  Per my proposal of
yesterday.

This should be noted as a source code change in the 8.4 release notes,
since it's likely to require changes in add-on modules.

the length of a UTF8 character with pg_mblen (wrong if DB encoding isn't
UTF8), and the latter was blithely assuming that a static buffer would somehow
revert to all zeroes for each use.

the timestamp types.  Turns out this doesn't even reduce the available
range of dates, since the restriction to dates that work for Julian-date
arithmetic is much tighter than the int32 range anyway.  Per a longstanding
TODO item.

Report and fix by Michael McMaster.  Some minor code beautification by me,
also avoid memory leaks in the special-case paths.

into nodes/nodeFuncs, so as to reduce wanton cross-subsystem #includes inside
the backend.  There's probably more that should be done along this line,
but this is a start anyway.

fix by Kris Jurka.

unnecessary #include lines in it.  Also, move some tuple routine prototypes and
macros to htup.h, which allows removal of heapam.h inclusion from some .c
files.

For this to work, a new header file access/sysattr.h needed to be created,
initially containing attribute numbers of system columns, for pg_dump usage.

While at it, make contrib ltree, intarray and hstore header files more
consistent with our header style.

These changes assume that the varchar and xml data types are represented
the same as text.  (I did not, however, accept the portions of the proposed
patch that wanted to assume bytea is the same as text --- tgl.)

Brendan Jurd

xmloption GUC variables into enums..

strings.  This patch introduces four support functions cstring_to_text,
cstring_to_text_with_len, text_to_cstring, and text_to_cstring_buffer, and
two macros CStringGetTextDatum and TextDatumGetCString.  A number of
existing macros that provided variants on these themes were removed.

Most of the places that need to make such conversions now require just one
function or macro call, in place of the multiple notational layers that used
to be needed.  There are no longer any direct calls of textout or textin,
and we got most of the places that were using handmade conversions via
memcpy (there may be a few still lurking, though).

This commit doesn't make any serious effort to eliminate transient memory
leaks caused by detoasting toasted text objects before they reach
text_to_cstring.  We changed PG_GETARG_TEXT_P to PG_GETARG_TEXT_PP in a few
places where it was easy, but much more could be done.

Brendan Jurd and Tom Lane

friends.  Avoid double translation of some messages, ensure other messages
are exposed for translation (and make them follow the style guidelines),
avoid unsafe passing of an unpredictable message text as a format string.

left in the code though it was not meant to be provided.  It represents a
security hole because unprivileged users could use it to look at (at least the
first line of) any file readable by the backend.  Fortunately, this is only
possible if the backend was built with XML support, so the damage is at least
mitigated; and 8.3 probably hasn't propagated into any security-critical uses
yet anyway.  Per report from Sergey Burladyan.

in whichever context happens to be current during a call of an xml.c function,
use a dedicated context that will not go away until we explicitly delete it
(which we do at transaction end or subtransaction abort).  This makes recovery
after an error much simpler --- we don't have to individually delete the data
structures created by libxml.  Also, we need to initialize and cleanup libxml
only once per transaction (if there's no error) instead of once per function
call, so it should be a bit faster.  We'll need to keep an eye out for
intra-transaction memory leaks, though.  Alvaro and Tom.

Therefore we must xmlCleanupParser(), or we risk leaving behind
dangling pointers to whatever memory context is current when xml_init()
is called.  This seems to fix bug #3860, though we might still want
the more invasive solution being worked on by Alvaro.

SPI_prepare() and SPI_cursor_open(), to silence a Coverity warning.

anyway, it is faster to memcpy() than to strcpy().

immutable and indexable.  Also fix the volatility settings of some other
XML-related functions.

happened to be right up against the end of memory, per report from
Matt Magoffin.  While at it, avoid useless multiple copying of string
by not depending on xmlStrncatNew.

avoid this problem in the future.)

spaces for consistency.  Per bug #3734 from Ben Leslie; fix by
Euler Taveira de Oliveira.

uninitialized value, and avoid invoking the function nine separate
times in the pg_xmlIsNameChar macro.  Should resolve buildfarm failures.
Per report from Ben Leslie.

those being exactly "xml".  Bug #3735 from Ben Leslie

Add some more xml_init() calls that might not be necessary, but seem like a
good idea to avoid possible problems like we saw in xmlelement().
Fix unsafe assumption that you can keep using the tupledesc of a relcache
entry you don't have open.
Add missing error checks for SearchSysCache failure.
Get rid of handwritten array traversal in xpath() and O(N^2), broken-for-nulls
array access code in map_sql_value_to_xml_value(), in favor of using
deconstruct_array.
Manually adjust a lot of line breaks in places where the code is otherwise
gonna look pretty awful after pg_indent hacks it up (original author seems to
have liked to lay out code for a 200-column window).

assuming that evaluation of its input expressions won't change the state of
libxml.  This requires refactoring xml_init() to not call xmlInitParser(),
since now not all of its callers want that.  I also tweaked things to avoid
repeated execution of one-time-only tests inside xml_init(), though this is
mostly for clarity rather than in hopes of saving any noticeable amount of
runtime.  Per report from Sheikh Amjad and subsequent discussion.
In passing, fix a couple of inadequately schema-qualified queries.

functions.  Patch for the reported issue from Kris Jurka, some
other potential trouble spots plugged by Tom.

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.