[Mono-dev] Issues with XElement.Load() & XmlReader.Create()

[Atsushi Eno]

1) I don't, without concrete patch. But any fixes are welcome.
2) That's non-issue, nor are we hobby copycats that are glad to
waste time on mimicking .net behavior.

Atsushi Eno

Sasha Kogan wrote:
> 
> 
> To reproduce the bug:
> 
> in MonoTests.System.Xml.Linq.XNodeReaderTest.CreateReader1() 
> (XNodeReaderTest.cs:43) replace  XDocument.Parse(xml) call with 
> XDocument.Parse(xml, LoadOptions.PreserveWhitespace).
> 
> The test will fail with the following stack:
> 
>  
> 
> System.InvalidOperationException: Node type None is not supported
> 
>    at System.Xml.Linq.XNode.ReadFrom(XmlReader r, LoadOptions options) 
> in 
> C:\MonoSVN\source\trunk\mcs\class\System.Xml.Linq\System.Xml.Linq\XNode.cs:line 
> 184
> 
>    at System.Xml.Linq.XContainer.ReadContentFrom(XmlReader reader, 
> LoadOptions options) in 
> C:\MonoSVN\source\trunk\mcs\class\System.Xml.Linq\System.Xml.Linq\XContainer.cs:line 
> 196
> 
>    at System.Xml.Linq.XElement.LoadCore(XmlReader r, LoadOptions 
> options) in 
> C:\MonoSVN\source\trunk\mcs\class\System.Xml.Linq\System.Xml.Linq\XElement.cs:line 
> 421
> 
>    at System.Xml.Linq.XElement.Load(XmlReader reader, LoadOptions 
> options) in 
> C:\MonoSVN\source\trunk\mcs\class\System.Xml.Linq\System.Xml.Linq\XElement.cs:line 
> 395
> 
>    at System.Xml.Linq.XNode.ReadFrom(XmlReader r, LoadOptions options) 
> in 
> C:\MonoSVN\source\trunk\mcs\class\System.Xml.Linq\System.Xml.Linq\XNode.cs:line 
> 152
> 
>    at System.Xml.Linq.XContainer.ReadContentFrom(XmlReader reader, 
> LoadOptions options) in 
> C:\MonoSVN\source\trunk\mcs\class\System.Xml.Linq\System.Xml.Linq\XContainer.cs:line 
> 196
> 
>    at System.Xml.Linq.XDocument.ReadContent(XmlReader reader, 
> LoadOptions options) in 
> C:\MonoSVN\source\trunk\mcs\class\System.Xml.Linq\System.Xml.Linq\XDocument.cs:line 
> 150
> 
>    at System.Xml.Linq.XDocument.LoadCore(XmlReader reader, LoadOptions 
> options) in 
> C:\MonoSVN\source\trunk\mcs\class\System.Xml.Linq\System.Xml.Linq\XDocument.cs:line 
> 135
> 
>    at System.Xml.Linq.XDocument.Load(TextReader reader, LoadOptions 
> options) in 
> C:\MonoSVN\source\trunk\mcs\class\System.Xml.Linq\System.Xml.Linq\XDocument.cs:line 
> 114
> 
>    at System.Xml.Linq.XDocument.Parse(String s, LoadOptions options) in 
> C:\MonoSVN\source\trunk\mcs\class\System.Xml.Linq\System.Xml.Linq\XDocument.cs:line 
> 173
> 
>    ...
> 
>  
> 
>    The failure is due to "using (XmlReader r = XmlReader.Create (reader, 
> s))" statement in XElement.cs:394.
> 
>    In some cases the instance returned by XmlReader.Create() is 'reader' 
> itself, thus r.Dispose() at the end of the recursive call invalidates 
> the reader and the
> 
>    attempt to process the next element fails.
> 
>    Although MS API states that XmlReader.Create(XmlReader reader, 
> XmlReaderSettings settings) returns a wrapper that uses the given 
> instance as an underlying reader,
> 
>    MS implementation returns 'reader' itself in some cases (I think 
> that's true iff 'settings' is same as 'reader''s settings, but I'm not 
> 100% sure). Mono behavior is different –
> 
>    it returns the instance itself or a wrapper depending on specific 
> flags in settings.
> 
>  
> 
>    The bottom line is that we have 2 issues here:
> 
>   
> 
>    1) XElement.Load() should not dispose the XmlReader instance upon 
> completion of recursive calls (if you approve, I’ll fix that).
> 
>    2) Inconsistent XmlReader.Create() behavior (meaning not consistent 
> with the API-breaking MS implementation...).
> 
>  
> 
> Pls your comments & suggestions.
> 
>  
> 
> ** /Sasha **
> 
>  
>