lxml.etree.XPathEvalError: Undefined namespace prefix

[slamer59]

Hello,
I want to make a diff with an archimate model (XML)

I have the following error

First model:

<?xml version="1.0" encoding="UTF-8"?>
<archimate:model xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:archimate="http://www.archimatetool.com/archimate" name="model_indep_1" id="id-1c8620d7bba6422daa2c194868f32e10" version="4.9.0">
  <folder name="Strategy" id="id-0701c8ef4dcc406488089b1540f80e60" type="strategy">
    <element xsi:type="archimate:Resource" name="Resource_1" id="id-2dc7c45e2dd740eb8a72c5726c13a748"/>
  </folder>
  <folder name="Business" id="id-3987d87d856c4bc9bc658c22c528bfd4" type="business"/>
  <folder name="Application" id="id-8ba93e0cda1c4d1e9b0ac95b5541830f" type="application"/>
  <folder name="Technology &amp; Physical" id="id-f1b639d8438f429c9105cf25addf0ed0" type="technology"/>
  <folder name="Motivation" id="id-5c8b65c0c4a9467dbfc30275a8f1f8c5" type="motivation"/>
  <folder name="Implementation &amp; Migration" id="id-7645db970d03422daa233d95d8aa7912" type="implementation_migration"/>
  <folder name="Other" id="id-238f0475a70442f08d2e39890c114506" type="other"/>
  <folder name="Relations" id="id-e44837d7eeac4b3587a59b0c6b42adba" type="relations"/>
  <folder name="Views" id="id-7af61afa9dba4d5aa16a3b65a2e295d0" type="diagrams">
    <element xsi:type="archimate:ArchimateDiagramModel" name="Default View" id="id-18eeb37134d743aa95f1ccb0910aae15">
      <child xsi:type="archimate:DiagramObject" id="id-339a26be3a4b413b98ac311837603ee1" archimateElement="id-2dc7c45e2dd740eb8a72c5726c13a748">
        <bounds x="455" y="323" width="120" height="55"/>
      </child>
    </element>
  </folder>
</archimate:model>

Second model:

<?xml version="1.0" encoding="UTF-8"?>
<archimate:model xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:archimate="http://www.archimatetool.com/archimate" name="model_indep_2" id="id-1c8620d7bba6422daa2c194868f32e10" version="4.9.0">
  <folder name="Strategy" id="id-0701c8ef4dcc406488089b1540f80e60" type="strategy">
    <element xsi:type="archimate:Resource" name="Resource_1" id="id-2dc7c45e2dd740eb8a72c5726c13a748"/>
  </folder>
  <folder name="Business" id="id-3987d87d856c4bc9bc658c22c528bfd4" type="business">
    <element xsi:type="archimate:BusinessActor" name="Business Actor" id="id-39d0e8e8a6d9468dada3aa69067010d9"/>
  </folder>
  <folder name="Application" id="id-8ba93e0cda1c4d1e9b0ac95b5541830f" type="application"/>
  <folder name="Technology &amp; Physical" id="id-f1b639d8438f429c9105cf25addf0ed0" type="technology"/>
  <folder name="Motivation" id="id-5c8b65c0c4a9467dbfc30275a8f1f8c5" type="motivation"/>
  <folder name="Implementation &amp; Migration" id="id-7645db970d03422daa233d95d8aa7912" type="implementation_migration"/>
  <folder name="Other" id="id-238f0475a70442f08d2e39890c114506" type="other"/>
  <folder name="Relations" id="id-e44837d7eeac4b3587a59b0c6b42adba" type="relations"/>
  <folder name="Views" id="id-7af61afa9dba4d5aa16a3b65a2e295d0" type="diagrams">
    <element xsi:type="archimate:ArchimateDiagramModel" name="Default View" id="id-18eeb37134d743aa95f1ccb0910aae15">
      <child xsi:type="archimate:DiagramObject" id="id-339a26be3a4b413b98ac311837603ee1" archimateElement="id-2dc7c45e2dd740eb8a72c5726c13a748">
        <bounds x="455" y="323" width="120" height="55"/>
      </child>
    </element>
  </folder>
</archimate:model>

Diff:

[update-attribute, /archimate:model[1], name, "model_indep_2"]
[move, /archimate:model/folder[2], /archimate:model[1], 6]
[insert, /archimate:model[1], folder, 1]
[insert-attribute, /archimate:model/folder[2], id, "id-3987d87d856c4bc9bc658c22c528bfd4"]
[insert-attribute, /archimate:model/folder[2], name, "Business"]
[insert-attribute, /archimate:model/folder[2], type, "business"]
[update-attribute, /archimate:model/folder[8], id, "id-e44837d7eeac4b3587a59b0c6b42adba"]
[update-attribute, /archimate:model/folder[8], name, "Relations"]
[update-attribute, /archimate:model/folder[8], type, "relations"]
[move, /archimate:model/folder[9], /archimate:model/folder[2], 0]
[rename, /archimate:model/folder[2]/folder[1], element]
[update-attribute, /archimate:model/folder[2]/element[1], id, "id-39d0e8e8a6d9468dada3aa69067010d9"]
[update-attribute, /archimate:model/folder[2]/element[1], name, "Business Actor"]
[insert-attribute, /archimate:model/folder[2]/element[1], {http://www.w3.org/2001/XMLSchema-instance}type, "archimate:BusinessActor"]
[delete-attribute, /archimate:model/folder[2]/element[1], type]

Here you can find the schema: http://www.opengroup.org/xsd/archimate/3.0/html-view/

How can I provide the namespace prefix archimate ?

[regebro]

I can't see any Undefined namespace prefix error? You got a diff out, then there you can't have gotten that error.
The diff is unnecessarily large, though.

This issue is easiest solved by specifying that "id" is a unique attribute in your files:

xmldiff --unique-attributes=id file1.xml file2.xml

But the matching here could be improved so that this isn't necessary.

[regebro]

I just had a brainwave when it comes to the node matching, so this will be improved in 2.5, which will be released soon.

[regebro]

And 2.6 improves namespace handling.