Bug#862405: libjson-xs-perl: dropped support for to_json

[Dominic Hargreaves]

Package: libjson-xs-perl
Version: 3.030-1
Severity: important

3.0 (released 2013) removed to_json/from_json with no further
information given
(https://sources.debian.net/src/libjson-xs-perl/3.030-1/Changes/#L40)

This seems to break a documented interface of libjson-perl's if installed.
I don't know the full history but it seems that there are other known
issues with JSON::XS not working nicely with JSON, and the recommendation
is to not use it at all.

https://rt.cpan.org/Public/Bug/Display.html?id=94784

This was observed with #848041 in request-tracker4. I'm honestly not sure
about the best route forward on that ticket; looking at the rdeps of
libjson-xs-perl, Conflicting on it may be too invasive...

Thoughts welcomed!

Dominic.