jackson-databind VS polars

Jackson had this problem a few months back, where someone reported a critical CVE against the project and broke builds all around the planet https://github.com/FasterXML/jackson-databind/issues/3972

Basically the programmer (not the attacker) had to write code where an object contained itself

HashMap map=new HashMap<>();

map.put("recursive",map);

After this, Jackson would indeed stack overflow if you asked it to wrap the object to JSON. Then again, half the build-in Java functions (e.g. getting an object hashcode for the map object) also fail for a recursive structure.

The issue remains open 3 months later, Mitre still thinks it's hella serious, and people have yet again learned to just ignore their CI warning about CVEs

jackson-databind maintainer responds to a similar occurrence few weeks ago: https://github.com/FasterXML/jackson-databind/issues/3972#is...

As to Jackson itself see https://github.com/FasterXML/jackson-databind/issues/1970 for example on startup issues. There are others.

after reading https://github.com/FasterXML/jackson-databind/issues/2239 but setting JsonCreator and adding the JsonFormat didn't work.

Jackson should support records out of the box https://github.com/FasterXML/jackson-databind/issues/2709

Its not like this vulnerability is something new. Similar issues have been public knowledge for at least four years and discussed widely. The fact that str to int and int to str conversions are slow for huge ints is hardly news.

In C#, Newtonsoft Json has similar functionality, and in Java — Jackson2 ObjectMapper.

This is because 0.1 is in actuality the floating point value value 0.1000000000000000055511151231257827021181583404541015625, and thus 1 divided by it is ever so slightly smaller than 10. Nevertheless, fpround(1 / fpround(1 / 10)) = 10 exactly.

I found out about this recently because in Polars I defined a // b for floats to be (a / b).floor(), which does return 10 for this computation. Since Python's correctly-rounded division is rather expensive, I chose to stick to this (more context: https://github.com/pola-rs/polars/issues/14596#issuecomment-...).

https://github.com/pola-rs/polars/releases/tag/py-0.19.0

That turned out to be related to pola-rs/polars#11912, and this linked comment provided a deceptively simple solution - use PARSE_DECLTYPES when creating the connection: