Re: [xml] State of schema validation

[Daniel Veillard <veillard redhat com>]

On Tue, Oct 26, 2010 at 09:42:33AM +0200, Marc Van Peteghem wrote:
> Hi,
>
> On http://xmlsoft.org/html/libxml-xmlschemas.html I read that validation of schemas is incomplete. Does 
> anybody know what is missing? The most recent message about this that I could find in the archives is from 
> March 2009, with a patch to solve a problem.

  Depends on your schemas. If you use things which are relatively
classic, you should be fine, but the Schemas spec has many grey areas.

<explicit>
 Have you tried to *read* it http://www.w3.org/TR/xmlschema-1/ for me
the structure part is mostly undecipherable jargon, just try to
extract from there the semantic of even a very simple schemas, needless
to say if there is a complex question I can't use the spec to try to
get an answer. Suppose you have a problem how am I supposed to handle
it considering this point and the fact that I don't have much time
for libxml2 ? My libxml2 support is mostly volunteer work, unless it's
a security issue where I can justify the time spent. And between
spending a few hours trying to decipher the spec and doing something
else for libxml2, the choice is rather obvious.
</explicit>

  If libxml2 Schemas support works for you, and this works for many people,
then fine use it, but if you have a problem, I can make no guarantee
that I will be able to help you. And to know what's missing, one would
need to understand all the spec, impossible for me.
  Sharp contrast with Relax-NG, where at least if there is a problem
I have no question about the semantic, it's "just" a matter of fixing
code (when possible).

  That said when people report obvious problems in XSD support I try to
plug it, if they have a patch that's even better, but in practice it
doesn't happen very often.

Daniel

-- 
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