Re: [xslt] Segmentation fault in the latest release by processing some DocBook XML files

["William M. Brack" <wbrack mmm com hk>]

Daniel Veillard wrote:
> On Thu, Jul 26, 2007 at 02:52:09PM +0200, Daniel Leidert wrote:
>> Hi,
>>
>> I normally wouldn't bother you directly, but the issue
>>
>> http://bugzilla.gnome.org/show_bug.cgi?id=459713
>>
>> prevents me from some important testing that needs to be done. Can you
>> have a look at it? I will provide any information you need.
>
>   Bill was looking at it yesterday.
> Any chance you could reduce this to a simpler example than the full
> DocBook stylesheets ? That would really make it less scary and help
> fixing it.
>   I can see how removing the namespace while it could still be in use
> in the subtree could really mess things up. It don't think one can
> xmlFreeNs(ns) at that point without taking huge risks.
>
>   Bill, do you remember wy you wanted to get rid of it ?
>

I remember it fairly well (which, in itself, is unusual for a person with
a memory as mature mine).  While checking on some other unrelated
problem, I noticed that, when running in the special test environment
which you and I use for all compilations, there was an error being
generated by debugXML concerning namespaces related to
exclude-result-prefixes processing.  I discussed it with you briefly on
the Chat channel, and you suggested that it might be better to leave it
alone, since 1) this only occurs when debugXML has been enabled, 2) there
had never been any problem reported with it, and 3) my suggested "fix"
for this included deleting the troublesome (duplicate) node, which you
warned me might cause trouble with pointers to the node which may have
been previously created.

However, being a "purist" at heart, I decided to go ahead and put in the
"fix", which very nicely took care of the debugXML warning.  Further, I
ran through all of the regression tests (including several for DocBook)
and convinced myself that there would be no problem.  Obviously, this has
been proven to be badly mistaken :-(.

I am, therefore, reverting the xslt.c code to it's previous state, and
will just close my eyes when the debugXML warning shows up again in the
future!

> Daniel
>
> --
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> Daniel Veillard      | virtualization library  http://libvirt.org/
> veillard redhat com  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
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Bill