Re: [xml] bug 362989

On Tue, Oct 31, 2006 at 08:00:59PM -0500, Daniel Veillard wrote:
On Tue, Oct 31, 2006 at 02:25:49PM -0800, Yong Chen (yongche) wrote:
This is the epsilon transition elimination in the graph of transition.
Each time someone tried to point out that the implementation of this function
was broken it was something else, it's just where the problem usually show
up, the error being the construction of the graph automata. Of course the
construct in the automata are a bit more complex than in the book.
  It is not trivial, it takes serious concentration and time to really
understand where the problem comes from. The bigger the example, the bigger
the automatas, the more time it takes. You may start to understand why I insist
on getting a reduced problem.

  I spent 3 hours on the problem, a large part of it trying to understand
your schemas. And I found a bug, really not obvious, and a couple of

  I would also like to raise the point of the 'niceness' of that schemas.
It seems to me trying to understand the semantic of that is near impossible,
  <xs:group ref="optional_group_4" minOccurs="0" maxOccurs="1"/>
looks like automatically generated schemas with names without semantic
constant references to labels, making even harder to get the full picture.
It's a bit like asking to debug code which was automatically generated
i.e. even more painful than when you can extract the semantic of the

  I guess you will appreciate the fact that I think I fixed the bug:

paphio:~/XML -> xmllint --timing --noout --schema 362989.xsd test.xml
362989.xsd:23: element complexType: Schemas parser error : complex type 'access-list_type': The content model 
is not determinist.
WXS schema 362989.xsd failed to compile
Compiling the schemas took 1195 ms
Parsing took 0 ms
Freeing took 0 ms
paphio:~/XML -> 

  I guess you now need to fix your schemas, it it not deterministic, and
hence should be rejected by any correct XSD implementation. Let's say I
really did *not* enjoy debugging in your schemas, still I'm kind and will
give you the reason leading to my believing it's broken:
    - see the content model for access-list_type
    - notice how all groups direct or derived use minOccurs="0"
    - notice how all elements in the content model also have minOccurs="0"
    - notice that element "src_addr" is defined by both
      block_group_18 and block_group_3
    - block_group_18 is referenced by block_group_17
    - block_group_3 is referenced by block_group_2
    - block_group_2 is referenced by access-list_type
    - block_group_17 is referenced by access-list_type

 so this can't be determinist, your schemas is broken


Red Hat Virtualization group
Daniel Veillard      | virtualization library
veillard redhat com  | libxml GNOME XML XSLT toolkit | Rpmfind RPM search engine

[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]