Jackson 2.10.x fails to deserialize xsi:nil with multiple child elements

[henrik242]

This XML:

<Silly xmlns:a="http://www.w3.org/2001/XMLSchema-instance" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
  <a:Hey i:nil="true"/>
  <a:Ho>to</a:Ho>
</Silly>

.. fails to properly deserialize in Jackson 2.10.x. Both Hey and Ho are null, while in 2.9.9 they were "" and "to".

See test project at https://github.com/henrik242/jackson-xml-problem/tree/jackson-xml-nil-problem

First reported in #354 (comment) and #358 (comment)

[henrik242]

Happy new year! Any ideas to a workaround or fix for this, @cowtowncoder ?

[cowtowncoder]

Happy new year!

No, unfortunately I have not had time to work on xml module. But I think I can probably add a failing test for this soon at least.

[cowtowncoder]

Hmmh. Ok, from some digging it looks like second element gets skipped for some reason.

[henrik242]

Happy new year! Weird. It's got something to do with using the http://www.w3.org/2001/XMLSchema-instance schema, at least.

[cowtowncoder]

Sort of; I think it is really "transformation" of element into null, skipping until end, and not properly synchronizing. I really should rewrite the backend, one of these days, but for that to happen would probably need one of 2 things to happen -- either finding XML to be higher priority than other formats (aside from json), or, find a way to maintain Jackson for living and not just as a hobby.
But I digress. :)

I think I can figure out a fix/work-around for this particular problem. It's just more difficult than it should be, because of complexity of backend implementation which at this point is patch-over-patch, transforming one stream of events into another with sort of minimal state keeping.

[henrik242]

Thanks!

[cowtowncoder]

2.10.2 now released, I hope things work as expected. Also, reports for other edge cases (if any) would be welcome.

[henrik242]

FasterXML/jackson-module-kotlin#396 might be related to this (jackson 2.12.0-rc1 regression)