Closed Bug 326994 Opened 18 years ago Closed 18 years ago

XMLSerializer adds namespace declaration for non-empty prefix with empty namespace name

Categories

(Core :: XML, defect)

Product:
Core
Component:
XML
Type:
defect
Priority:
Not set
Severity:
normal

Tracking

()

Status:
RESOLVED FIXED

People

(Reporter: surkov, Assigned: peterv)

References

Details

Attachments

(2 files, 3 obsolete files)

v1
5.52 KB, patch
bzbarsky
: review+
bzbarsky
: superreview+
Details | Diff | Splinter Review
Testcase
4.14 KB, application/xml
Details 
User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.9a1) Gecko/20051212 Firefox/1.6a1
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.9a1) Gecko/20051212 Firefox/1.6a1

When instance is created dynamically then instance document submitted with namespace prefix "a0". Something like that: 
<a0:root xmlns:a0="" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"/>

The problem is DOMParser fails when it parse such document.

Probably it is isn't xforms problem and I just want to understand what's happen.

Reproducible: Always
Attached file testcase (obsolete) — 

    
    

    
  

      
      
      
      

        Attached file
          
        testcase (obsolete)
        — 
      

    


  

        Attachment #211719 -
        Attachment is obsolete: true

    
    

    
  

      
      
      
      

        Attached file
          
        xml parse feature (obsolete)
        — 
      

    


  
The first issue isn't related with XForms. I'm not sure whether the issue is bug or not but the strange behaviour surely. If element has attribute xmlns="uri1" and I set attribute xmlns="uri2" on it then element has two attributes xmlns="uri2" and xmlns:a0="uri1". When I serialize the element and then I parse it then I get exception.

    
    

    
  
The second issue is related with xforms, and it probably isn't a bug too. But I guess it is needed in some discussion. The question is following. If instance document root contains default empty namespace (xmlns="") then why we should change default namespace on it from owner document? In instance:

<html xmlns="xhtml namespace uri"
      xmlns:xforms="xforms namespace uri">

<xforms:model>
  <xforms:instance>
    <instanceRoot xmlns=""/>
  </xforms:instance>
</xforms:model>

</html>

Result:
<a0:instanceRoot xmlns:a0="" xmlns="html namespace uri"/>

I can't see the utility of it. Any reason?

    
  

        Attachment #211720 -
        Attachment mime type: text/plain → application/xhtml+xml

    
    

    
  
Hmm, there seems to be something weird happening. At least you should be able to serialize some XML, and then parse it afterwards.

Peter, can you educate us here? :)

    
    

    
  
About what?

    
    

    
  
(In reply to comment #6)
> About what?

About why we get a parseerror in attachment 211807 [details]

This happens on trunk, but on on 1.8.0.

    
    

    
  
You need to use setAttributeNS to set xmlns attributes. You're adding a xmlns attribute with no namespace, there's no good way to serialize that. Also see http://lxr.mozilla.org/seamonkey/source/content/base/src/nsXMLContentSerializer.cpp#600

    
    

    
  
IMHO we should throw on the setAttribute call.

    
    

    
  
(In reply to comment #8)
> You need to use setAttributeNS to set xmlns attributes. You're adding a xmlns
> attribute with no namespace, there's no good way to serialize that. Also see
> http://lxr.mozilla.org/seamonkey/source/content/base/src/nsXMLContentSerializer.cpp#600

Ah.

(In reply to comment #9)
> IMHO we should throw on the setAttribute call.

That would be nice. I would have caught the error earlier at least.

    
    

    
  
(In reply to comment #8)
> You need to use setAttributeNS to set xmlns attributes. You're adding a xmlns
> attribute with no namespace, there's no good way to serialize that. Also see
> http://lxr.mozilla.org/seamonkey/source/content/base/src/nsXMLContentSerializer.cpp#600
> 

Do you mean I should write the something like that?

root.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns", "http://www.w3.org/1999/xhtml");

The behaviour remains the same.

    
    

    
  
(In reply to comment #4)
> The second issue is related with xforms, and it probably isn't a bug too. But I
> guess it is needed in some discussion. The question is following. If instance
> document root contains default empty namespace (xmlns="") then why we should
> change default namespace on it from owner document? 
> 
> I can't see the utility of it. Any reason?
> 

I can't find anything in the specs about inheritance default namespace. Note, if I understand right, model owner document, model element, instance element and instance document can have different default namespaces. There is not a way to control default naemspaces. Imo the default namespaces should not be inherited. Am I wrong?

Btw #default value in @includenamespaceprefixes isn't supported.

    
    

    
  
Morphing this bug, please file the XForms issue as a separate bug if it is one. We should not add a namespace declaration for a non-empty prefix with an empty namespace name, see http://www.w3.org/TR/REC-xml-names/#dt-prefix
Assignee: aaronr → xml
Status: UNCONFIRMED → NEW
Component: XForms → XML
Ever confirmed: true
QA Contact: spride → ashshbhatt
Summary: dynamic instance submission issue → XMLSerializer adds namespace declaration for non-empty prefix with empty namespace name

    
    

    
  

      
      
      
      

        Attached patch
          
          
        v1
        — 
          — Splinter Review
      

    


  
Boris, what do you think? This patch makes us drop an attribute in the case of:

  var doc = ParseXML('<root xmlns=""/>')
  var root = doc.documentElement;
  root.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns",
                      "http://www.w3.org/1999/xhtml");

so when serializing root we end up with:

<root/>

The alternative is to output:

<root xmlns:a0="http://www.w3.org/1999/xhtml"/>

Note that in the case of

  var doc = ParseXML('<root xmlns="http://www.w3.org/1999/xhtml"/>')
  var root = doc.documentElement;
  root.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns",
                      "");

we output:

<a0:root xmlns:a0="http://www.w3.org/1999/xhtml" xmlns=""/>
Assignee: xml → peterv
Status: NEW → ASSIGNED

        Attachment #212110 -
        Flags: superreview?(bzbarsky)

        Attachment #212110 -
        Flags: review?(bzbarsky)

    
    

    
  

      
      
      
      

        Attached file
          
        Testcase
        — 
      

    


  

        Attachment #211720 -
        Attachment is obsolete: true

        Attachment #211807 -
        Attachment is obsolete: true

    
    

    
  
Comment on attachment 212110 [details] [diff] [review]
v1

>Index: content/base/src/nsXMLContentSerializer.cpp
>+          skipAttr = index;

Right before that, assert that skipAttr == count?  Or can we not do that?  That is, can we have two separate prefix-less "xmlns" attrs?  If we can, it seems like this fix won't work...

Or is the plan to do this and then throw on prefix-less xmlns attrs not in the xmlns namespace?

r+sr=bzbasky with that sorted out.

        Attachment #212110 -
        Flags: superreview?(bzbarsky)

        Attachment #212110 -
        Flags: superreview+

        Attachment #212110 -
        Flags: review?(bzbarsky)

        Attachment #212110 -
        Flags: review+

    
    

    
  
(In reply to comment #16)
> Or is the plan to do this and then throw on prefix-less xmlns attrs not in the
> xmlns namespace?

Yes, and it's bug 315805.

    
  
Status: ASSIGNED → RESOLVED
Closed: 18 years ago
Resolution: --- → FIXED
Blocks: 301260

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