Re: [xml] XPath crashes with 2.6.27 - any workaround?

[Daniel Veillard <veillard redhat com>]

On Mon, Sep 17, 2007 at 05:58:52PM +0200, Stefan Behnel wrote:
> Hi,
> 
> we keep getting bug reports from lxml users about XPath crashes with libxml2
> 2.6.27 when errors occur (such as an unknown function). This has been fixed in
> 2.6.28, however, 2.6.27 happens to be pretty frequently installed on Linux
> systems, so people keep using it and then complain when it crashes.

  Sorry, backport of bug fixes is left as a work for the distro maintainance.
I do that for RHEL for example, otherwise, either upgrade or get the given
distro to distribute a bug fix. That's one of the places where distributions
can actually compete, but here in upstream we fix bugs in head.
  Different goals, different jobs, different prices.

> Is there anything we could try to work around this problem? I would at least
> like to detect it when errors occur *before* libxml2 crashes.

  Since I don't know how the error manifests itself, I can't answer how you
could prevent it, but IIRC it's a double free in an XPath evaluation, I see
no way to catch that upfront exept doing preanalysis of queries.
  The version number is available from the API if you want to warn.

Daniel

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