canonicalize crashes on namespace with no prefix

[Paul Prescod]

https://repl.it/repls/TrustworthyStimulatingRedundancy

Python : sys.version_info(major=3, minor=8, micro=1, releaselevel='final', serial=0)
lxml.etree : (4, 5, 0, 0)
libxml used : (2, 9, 10)
libxml compiled : (2, 9, 10)
libxslt used : (1, 1, 34)
libxslt compiled : (1, 1, 34)

Script:

xml="""
<X xmlns="http://soap.sforce.com/2006/04/metadata">
    <Y targets="lightning__AppPage,lightning__HomePage"></Y>
</X>"""
print(etree.canonicalize(xml))

Exception:

  File "src/lxml/serializer.pxi", line 1079, in lxml.etree.C14NWriterTarget._qname
ValueError: Namespace "" is not declared in scope

[scoder (scoder)]

Interesting. Thanks for reporting this (and sorry for missing it earlier this year).
This also needs fixing in CPython then, since both ElementTree and lxml are using (mostly) the same implementation here.

[scoder (scoder)]

https://github.com/lxml/lxml/commit/45aa5a1cf518ba529afb56a55150bcec683cf2e4

[scoder (scoder)]

Proposed fix for CPython is here:
https://github.com/python/cpython/pull/22474

[Paul Prescod (prescod)]

Thank you!

On Sun, Oct 18, 2020 at 6:50 AM scoder <email address hidden> wrote:

> ** Changed in: lxml
> Status: Fix Committed => Fix Released
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1869455
>
> Title:
> canonicalize crashes on namespace with no prefix
>
> Status in lxml:
> Fix Released
>
> Bug description:
> https://repl.it/repls/TrustworthyStimulatingRedundancy
>
> Python : sys.version_info(major=3, minor=8, micro=1,
> releaselevel='final', serial=0)
> lxml.etree : (4, 5, 0, 0)
> libxml used : (2, 9, 10)
> libxml compiled : (2, 9, 10)
> libxslt used : (1, 1, 34)
> libxslt compiled : (1, 1, 34)
>
> Script:
>
> xml="""
> <X xmlns="http://soap.sforce.com/2006/04/metadata">
> <Y targets="lightning__AppPage,lightning__HomePage"></Y>
> </X>"""
> print(etree.canonicalize(xml))
>
> Exception:
>
> File "src/lxml/serializer.pxi", line 1079, in
> lxml.etree.C14NWriterTarget._qname
> ValueError: Namespace "" is not declared in scope
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/lxml/+bug/1869455/+subscriptions
>