Re: [xml] Problem with data in interleave in RELAX NG validation

[Daniel Veillard <veillard redhat com>]

On Sun, Oct 14, 2018 at 09:02:29PM +0200, Nikolai Weibull via xml wrote:
> Hi!
>
> OK, I managed to decode it somewhat.  The issue seems to be that we build
> groups of what can be matched by the interleave, but that these groups don’t
> include data, list, and value elements, only element and text elements.

  this may be an oversight when going from the RNG data model to what
is the libxml2 insternal structures reflecting this. Among the mismatches
are also TEXT vs CDATA which are separated in libxml2 model and unified as
simple text nodes in the RelaxNG one.

> This patch extends xmlRelaxNGGetElements so that it can return these
> elements for us in xmlRelaxNGComputeInterleaves.  Then we make sure to
> updatexmlRelaxNGNodeMatchesList as well so that it accepts the correct
> types.

  That sounds reasonable

> The testsuite passes and my test below does as well.
>
> I’m a bit surprised that interleaves simply wouldn’t allow for data, list,
> and value elements previously, so I’m wondering if there was a reason for
> the code to be the way it was and that the fix should be placed somewhere
> else or if it was simply an oversight.  Either way, this does seem to be the

  I honnestly can't remember !

> correct solution. If someone could confirm that this solution is what we’re
> looking for, I’ll add some proper test cases and apply another merge request
> on git.gnome.org.

  This indeed seems to be working, would you mind sending patches to add
regression tests for this, that way I can incorporate those into an upcoming
release.

   thanks a lot !

Daniel

> Best regards,
>  Nikolai
>
> ---
> relaxng.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/relaxng.c b/relaxng.c
> index 8306e546..3ed03ff4 100644
> --- a/relaxng.c
> +++ b/relaxng.c
> @@ -3993,7 +3993,7 @@ xmlRelaxNGGenerateAttributes(xmlRelaxNGParserCtxtPtr
> ctxt,
>  * xmlRelaxNGGetElements:
>  * @ctxt:  a Relax-NG parser context
>  * @def:  the definition definition
> - * @eora:  gather elements (0) or attributes (1)
> + * @eora:  gather elements (0), attributes (1) or elements and text (2)
>  *
>  * Compute the list of top elements a definition can generate
>  *
> @@ -4019,7 +4019,12 @@ xmlRelaxNGGetElements(xmlRelaxNGParserCtxtPtr ctxt,
>     while (cur != NULL) {
>         if (((eora == 0) && ((cur->type == XML_RELAXNG_ELEMENT)         ||
>                              (cur->type == XML_RELAXNG_TEXT))) ||
> -            ((eora == 1) && (cur->type ==
> XML_RELAXNG_ATTRIBUTE))) {
> +            ((eora == 1) && (cur->type == XML_RELAXNG_ATTRIBUTE)) ||
> +            ((eora == 2) && ((cur->type == XML_RELAXNG_DATATYPE) ||
> +                             (cur->type == XML_RELAXNG_ELEMENT) ||
> +                             (cur->type == XML_RELAXNG_LIST) ||
> +                             (cur->type == XML_RELAXNG_TEXT) ||
> +                             (cur->type == XML_RELAXNG_VALUE)))) {
>             if (ret == NULL) {
>                 max = 10;
>                 ret = (xmlRelaxNGDefinePtr *)
> @@ -4374,7 +4379,7 @@ xmlRelaxNGComputeInterleaves(void *payload, void
> *data,
>         if (cur->type == XML_RELAXNG_TEXT)
>             is_mixed++;
>         groups[nbgroups]->rule = cur;
> -        groups[nbgroups]->defs = xmlRelaxNGGetElements(ctxt, cur,
> 0);
> +        groups[nbgroups]->defs = xmlRelaxNGGetElements(ctxt, cur, 2);
>         groups[nbgroups]->attrs = xmlRelaxNGGetElements(ctxt,         cur,
> 1);
>         nbgroups++;
>         cur = cur->next;
> @@ -9280,7 +9285,10 @@ xmlRelaxNGNodeMatchesList(xmlNodePtr node,
> xmlRelaxNGDefinePtr * list)
>                 return (1);
>         } else if (((node->type == XML_TEXT_NODE) ||
>                     (node->type == XML_CDATA_SECTION_NODE)) &&
> -                   (cur->type == XML_RELAXNG_TEXT)) {
> +                   ((cur->type == XML_RELAXNG_DATATYPE) ||
> +                    (cur->type == XML_RELAXNG_LIST) ||
> +                    (cur->type == XML_RELAXNG_TEXT) ||
> +                    (cur->type == XML_RELAXNG_VALUE))) {
>             return (1);
>         }
>         cur = list[i++];
> -- 
> 2.19.1
>
>
> Nikolai Weibull, 2018-10-13 00:23:
>
> > Hi!
> >
> > This remains unfixed.  I have absolutely no idea what’s going on in
> > the interleave validation code.  Daniel, could you please put together
> > some minor documentation on how the interleave validation code works?
> > It’s very complicated.
> >
> > Thank you,
> >
> >  Nikolai
> >
> > Nikolai Weibull, 2018-09-09 21:26:
> >
> > > Hi!
> > >
> > > Given the following input RELAX NG grammar:
> > >
> > > <grammar xmlns="http://relaxng.org/ns/structure/1.0";
> > >         datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes";>
> > >  <start>
> > >    <element name="a">
> > >      <interleave>
> > >        <attribute name="b"/>
> > >        <data type="string"/>
> > >      </interleave>
> > >    </element>
> > >  </start>
> > > </grammar>
> > >
> > > and the following input document a.xml:
> > >
> > > <a b="1">c</a>
> > >
> > > xmllint reports:
> > >
> > > a.xml:1: element a: Relax-NG validity error : Element a has extra
> > > content: text
> > > a.xml fails to validate
> > >
> > > Changing the interleave to a group solves the issue, so the problem
> > > is
> > > with how interleaves are validated.
> > >
> > > I looked at xmlRelaxNGValidateInterleave() and I sadly have no idea
> > > what’s going on.  Please point me in the right direction and I’ll
> > > gladly write a patch.
> > >
> > >  Nikolai
>
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Daniel Veillard      | Red Hat Developers Tools http://developer.redhat.com/
veillard redhat com  | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
http://veillard.com/ | virtualization library  http://libvirt.org/