Re: xpath processing brain dead

On Thu, Feb 26, 2009 at 3:18 PM, Andrew Dunstan <andrew(at)dunslane(dot)net> wrote:
>> I dunno, aren't XML document fragments sort of a pretty common case?
>
> They are. So what? How does that contradict either of the statements made
> above?
>
> Programmers using libxml2 are used to handling this problem. Why must
> postgres alone use a totally brain dead and utterly incorrect wrapping to
> solve a problem that everyone else leaves up to the programmer to handle?

I can't think of any reason, especially not when you put it that way. :-)

> People in this thread are not concentrating on the fact that what we do now
> can break correct input. That makes it an unquestionable bug, IMNSHO. There
> seems to be agreement about what to do for 8.4, so we seem to be arguing
> about what to do for 8.3. Are you *really* arguing that prepending the xpath
> expression with '/x' in all cases should be allowed to continue? If you are
> I can only assume your use of xml/xpath is probably fairly light.

Mine is very light indeed. But the change you're proposing seems like
it could CONCEIVABLY break a working application that counts on
PostgreSQL's particular flavor of misbehavior, and therefore it seems
questionable to put that into a stable branch. The fact that the
application perhaps should not have been written that way to begin
with is neither here nor there. We don't want people to be afraid of
upgrading to the latest point release when we fix, say, a backend
crash or a data corruption bug.

...Robert