[Expat-bugs] [ expat-Bugs-692964 ] Case where expat 1.95.6 doesn't report duplicate attributes.

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Bugs item #692964, was opened at 2003-02-25 10:28
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Category: None
Group: None
Status: Open
Resolution: Accepted
Priority: 5
Submitted By: Mark E. (snowballville)
Assigned to: Karl Waclawek (kwaclaw)
Summary: Case where expat 1.95.6 doesn't report duplicate attributes.

Initial Comment:
I believe I found a bug in the Expat parser in
detecting duplicate attributes when using namespaces.
I'm using Expat 1.95.6 with PyXML 0.8.2.

Section 6.3 of the Namespaces 1.1 recommendation
requires that no element have two attributes with the
same expanded name. Expat 1.95.6 does indeed report a
duplicate attribute error with the example given in
that section of the document:
<?xml version="1.1"?>
<x xmlns:n1="http://www.w3.org" 
   xmlns:n2="http://www.w3.org" >
  <bad a="1"     a="2" />
  <bad n1:a="1"  n2:a="2" />
</x>

I've attached a file with the first <bad> element
removed. Expat doesn't report a duplicate attribute
error when processing this file as I believe the
recommendation requires.


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>Comment By: Mark E. (snowballville)
Date: 2003-02-25 17:33

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I tried expat 1.95.5 with the same result.


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Comment By: Karl Waclawek (kwaclaw)
Date: 2003-02-25 14:02

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Well, if it is not too much effort, it certainly would
be useful information. Thanks,

Karl

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Comment By: Mark E. (snowballville)
Date: 2003-02-25 13:24

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Correction: I have used expat 1.95.5 (with pyxml 0.8.1), but
I haven't tested this case with it. I will if you want me
to. I would expect the same result though.


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Comment By: Karl Waclawek (kwaclaw)
Date: 2003-02-25 13:23

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It looks to me as if this error has always been there,
since the modifications required would be significant.
No need to test 1.95.5.

Karl

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Comment By: Mark E. (snowballville)
Date: 2003-02-25 13:21

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I just got started with using xml with python, so expat
1.95.6 (installed with pyxml 0.8.2) is the only version I've
used. I could temporarily download to pyxml 0.8.1 (which
includes expat 1.95.5) if you think it informative.


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Comment By: Karl Waclawek (kwaclaw)
Date: 2003-02-25 11:35

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Had a look. Won't be a quick fix.
The problem function is StoreAtts().

The solution might be to have a separate function
getAttributeIdNS() that looks up attribute id structs
by expanded instead of prefixed name.

But that may require adjustments to other parts of
the code. Hope I have time soon, unless someone else
is quicker.

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Comment By: Karl Waclawek (kwaclaw)
Date: 2003-02-25 10:44

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Expat only supports XML Namespaces 1.0, but the bug
still applies (section 5.3 of the spec).
Will look into it.

Does this happen with previous versions of Expat?

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