113438 - bugzilla.dtd is wrong

Status: RESOLVED FIXED

(Bugzilla :: Bugzilla-General, defect, P3)

Description

[Jochen Rollwagen]

The dtd of the bugzilla-distribution is wrong and leads to XML-Parser-Errors 
when reading bugs created by xml.cgi. Specifically, long_desc? has to be 
replaced by long_desc*, since there may be one or more long_desc's of a bug.

Comment 1

[Jan]

Attachment: valid dtd for bugzilla

valid dtd which can be used to validate complete bugzilla xml docs

Comment 2

[Jan]

Attachment: valid dtd for bugzilla (option 2)

valid dtd which can be used for validating bugzilla xml docs. Even xml docs
containing just 
<bug error="NotFound">
  <bug_id>133400</bug_id> 
</bug> 
will be validated correctly (in contrast to bugzilla-option1.dtd

Comment 3

[Jacob Steenhagen]

This is probably an error in libxml2, but I'll mention it here anyway since I
don't know for sure :)

I was working on using XML::LibXML (which is an "Interface to the gnome libxml2
library" - http://search.cpan.org/doc/MSERGEANT/XML-LibXML-1.31/LibXML.pm), and
came across the $doc->is_valid() method.  I got the following results:

bugzilla.dtd as found in CVS:
    It always reports and invalid document

"option 1" attached here:
    Valid for normal bugs
    Invalid for bugs that are NotPermitted or NotFound (as expected)

"option 2" attached here:
    Valid for bug that are NotPermitted or NotFound
    core dump for normal bugs (stating an "Illegal Instruction")

I don't know enough about DTD's to be certain that the synax used in the
<!ELEMENT bug> is correct or not, so I don't know for sure if this in an error
with this DTD or with libxml2 (or even XML::LibXML).

Comment 4

[Jacob Steenhagen]

Reassigning to author...

Jan, see my previous comment.

Comment 5

[Jan]

Hi,

the syntax of the "option 2" DTD should be okay according "3.2.1 Element 
Content" of W3C XML Recommendation (see http://www.w3.org/TR/2000/REC-xml-
20001006 ).

Comment 6

[Jan]

Attachment: bugzilla final version 1 DTD

Comment 7

[Jan]

Hi,

I had a closer look at the XML spec and bugzilla dtd (option 2): 

Unfortunately the dtd (option 2) leads to a non-deterministic content model 
which is not conform to the XML spec, I cite from the XML spec:

################################
The content of an element matches a content model if and only if it is possible 
to trace out a path through the content model, obeying the sequence, choice, 
and repetition operators and matching each element in the content against an 
element type in the content model. For compatibility, it is an error if an 
element in the document can match more than one occurrence of an element type 
in the content model. For more information, see E Deterministic Content Models.

E Deterministic Content Models (Non-Normative)
As noted in 3.2.1 Element Content, it is required that content models in 
element type declarations be deterministic. This requirement is for 
compatibility with SGML (which calls deterministic content 
models "unambiguous"); XML processors built using SGML systems may flag non-
deterministic content models as errors.

For example, the content model ((b, c) | (b, d)) is non-deterministic, because 
given an initial b the XML processor cannot know which b in the model is being 
matched without looking ahead to see which element follows the b. In this case, 
the two references to b can be collapsed into a single reference, making the 
model read (b, (c | d)). An initial b now clearly matches only a single name in 
the content model. The processor doesn't need to look ahead to see what 
follows; either c or d would be accepted.

################################

CONCLUSION:

!!! do not use bugzilla option 2 dtd because it is non-deterministic !!!


SOLUTION:

Use the "bugzilla final version 1 dtd" which I attached. Please check whether 
this
dtd works for you. I checked it with XML-Spy, generated an XML Schema from
this dtd with Tamino Schema editor and loaded this XML schema into Tamino. 
Now it is possible to store and retrieve bugzilla xml docs using Software AG's
Tamino XML server.

Best regards,

Jan

Comment 8

[Jacob Steenhagen]

Comment on attachment 63969 [details]
bugzilla final version 1 DTD

With this last revision, xml.cgi output on my local install validates properly
and doesn't cause LibXML to crash.  Low risk as it only effects XML output
validation, so no second review needed.

Comment 9

[Jacob Steenhagen]

Checking in bugzilla.dtd;
/cvsroot/mozilla/webtools/bugzilla/bugzilla.dtd,v  <--  bugzilla.dtd
new revision: 1.4; previous revision: 1.3
done

Comment 10

[Bradley Baetz (:bbaetz)]

Comment on attachment 63969 [details]
bugzilla final version 1 DTD

Yeah, but it misses the InvalidBugId error I added as part of the taint
stuff.....

Comment 11

[Bradley Baetz (:bbaetz)]

but jake fixed that, so ignore me ;)

Comment 12

[Jacob Steenhagen]

Gotta click that darned Resolve button :)