This project is now incorporated into Apache Spark. Could you open the pull request there? if it's accepted, I will back-port it here just in case.

Can you give an example of what no longer works (and should not), and/or what didn't work before and does now?

Thanks for the quick response @srowen! Looks like it's being added to spark 4.0 here https://github.com/apache/spark/blame/29d077fbbd5464f64e0eeb495f7a955850915cc5/sql/core/src/main/scala/org/apache/spark/sql/functions.scala#L7146? Reading this path it seems like it isn't using the same constructor as this library so I think we should be good to just back port this here?

I can't think of an example of something that doesn't work now that would have worked before...

Cases that previously didn't work and do now:

from_xml(new Literal("<root><name>foo</name></root>"), schema) <- string literal is read by the SQL parser as sql which is clearly isn't.
functions.transform(new Column("array"), (element, _index) -> from_xml(element, schema)) <- the variable reference is removed here when you use the SQL parser so this throws when planning.

@srowen is there a way for us to tag a new version for this fix?

Possibly, but does this block anything? it seems like the issues it avoids are things the caller can just not do, or do I misunderstand

I got around this by under the underlying spark expression rather than using functions so yes there's a work around but it's causing unexpected errors at the moment when using string literals and when used within an array transform.

I just released 0.18.0 with this change: https://github.com/databricks/spark-xml/releases/tag/v0.18.0