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Remove outdated method='c14n' references from ElementTree #118318
Description
Feature or enhancement
Proposal:
Remove some unused code and docstring descriptions.
Some references to a removed c14n serialization method remained in ElementTree.py. Attempting to use method='c14n' in the write() method would result in ValueError: unknown method 'c14n'.
Removes the write_c14n() method that uses method='c14n' and also raises the same error.
Has this already been discussed elsewhere?
This is a minor feature, which does not need previous discussion elsewhere
Links to previous discussion of this feature:
No response
Activity
danielquinn commentedon Apr 21, 2025
I just wasted about an hour trying to figure out why
c14nwasn't working, only to find this issue. Removal sounds like an obvious move.serhiy-storchaka commentedon May 24, 2026
@scoder, what are your thoughts?
scoder commentedon May 24, 2026
Hmm, right. Fredrik's original
ElementC14N.pymodule never made its way into CPython.lxml uses
method="c14n"for C14N version 1 andmethod="c14n2"for version 2.xml.etreecould support the latter but not currently the first, though that is the one that is documented.Since this never worked, removing it seems fine.
Making
method="c14n2"work in CPython would require a bit of work to map an existing tree to theC14NWriterTarget(or a parser target in general). Certainly a cool feature, but it would be a new feature, independent of the currently documentedc14nserialisation method. lxml uses itsiterwalk()tool for this (likeiterparse(), just not as a parser but for existing trees):https://github.com/lxml/lxml/blob/0e9989972a6c430277f962054db9c4cf19ec28c0/src/lxml/serializer.pxi#L928-L948
But this could probably be implemented quite easily using a recursive tree walker function.
So, yes, remove the existing dead&confusing option and method, and then (independently) consider adding
method="c14n2"as a new feature, duplicating the C14N serialisation optionswith_commentsandstrip_texttoET.write()andtostring(). (Or, which might be a more general feature, allow serialising to a parser Target object.)gh-118318: Remove outdated c14n references from ElementTree (GH-118319)
pythongh-118318: Remove outdated c14n references from ElementTree (py…