Re: contrib/xml2 vs core xml in 8.3

On Sun, Feb 28, 2010 at 06:57:33PM -0500, Tom Lane wrote:
> So I started to work on back-patching the no-pallocs change in xml2.
> It seems to work fine in 8.4, but it crashes in 8.3. The reason is
> that we never back-patched the 8.4 change to make utils/adt/xml.c
> not change the libxml2 memory allocation functions. That means that
> if you try to intermix core xml operations with contrib/xml2
> operations, it fails because libxml2 is still trying to use the
> core's substituted memory alloc functions, and the contrib module
> isn't doing what's needful to make those actually work.
>
> This may explain the previous observations that 8.3's contrib/xml2
> didn't crash in as many cases as 8.4's does. If core and contrib
> code both replace the allocation hooks, they're somewhat independent
> of each other. When only one does, big trouble is what you've got.
>
> It seems like the most rational response to this is to go ahead and
> back-patch the 8.4 changes, specifically this patch
> http://archives.postgresql.org/pgsql-committers/2009-05/msg00229.php
> into 8.3 so that we can also fix xml2. I was afraid to do that back
> in May when the patch was committed, but by now we have enough field
> testing to suggest that 8.4 is no worse than 8.3 as far as the core
> xml operations go.
>
> Comments?

+1 for back-patching.

Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david(dot)fetter(at)gmail(dot)com
iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics

Remember to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate