[Mono-list] XmlTextReader: MS compatibility, or W3C conformance?

Atsushi Eno atsushi@ximian.com
Fri, 09 Jul 2004 13:18:29 +0900

Ian MacLean wrote:

> Atsushi Eno wrote:
>> Hello,
>> On bugzilla we (Ian and I) were discussing on XmlTextReader conformance
>> to XML specification. MS XmlTextReader is buggy since it accepts
>> XML declaration as element content (that violates W3C XML specification
>> section 3 Logical Structures).
>> http://bugzilla.ximian.com/show_bug.cgi?id=61274
>> However, there is another discussion that it is useful that new
>> XmlTextReader (xmlText, XmlNodeType.Element, null) accepts XML 
>> declaration.
>> Well, I agree that
>>     - that error-prone XmlTextReader might be useful (especially
>>       for people who already depends on that behavior).
>>     - we did not always reject Microsoft badness; for example
>>       we are copying System.Xml.XmlCDataSection that violates
>>       W3C DOM interface hierarchy (!)
>> So it is case by case. I believe we should not allow such use of
>> XmlTextReader, but I understand what Ian wants me to do. The "fix"
>> can be very easily done.
>> I don't think it is major problem. Users can easily fix this problem
>> by calling MoveToContent(), or by skipping XmlDeclaration node with
>> Read() method (well, to call Read() safely, users have to check if
>> the reader state is Initial or not).
> Its not a major problem but your workaround above only works if every 
> fragment you want to parse follows Document constraints - eg single root 
> node. What I have done now is check the incoming xml fragment for an xml 
> decl and if present use XmlNodeType.Document otherwise use 
> XmlNodeType.Element.

If XmlTextReader created with XmlNodeType.Element does not accept
multiple top-level element, that is a bug (if so, please create
another bugzilla entry). If you want such xml that has "XML
declaration and multiple top-level elements", that sounds curious
needs and I wonder what kind of use case appreciates such fix :-?

Atsushi Eno