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

[Ross Reedstrom <reedstrm rice edu>]

Nikolai - 
Glad to see someone attacking these. I've got some RNG schema that we've
had to use jing to validate, since libxml2 was giving similiar issues to
what you're seeing, and I was even more daunted by the code than you
seem to be. If you could get this branch somewhere I can pull it down,
I'd love to see if your fixes help my schema.

Ross


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 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.
>
> 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
> 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.
>
> 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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-- 
Ross Reedstrom, Ph.D.                                 reedstrm rice edu
Senior Developer         https://cnx.org            phone: 713-348-6166
OpenStax                 https://openstax.org         fax: 713-348-3665
Rice University MS-375, Houston, TX 77005
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