Kanstantsin Shautsou Thank you for the response.
Rob Winch will it be possible to create Proxy or backward compatible migration?
Unfortunately, I don't think there is a way to make the transition completely seamless (i.e. using a Proxy). There may be steps we can provide to make the transition easier. However, this is difficult to determine at this point since I'm not familiar with the Jenkins code base.
If not, could you provide some PR to core (there is a spring-security branch but with 0 work).
Although not clear, my initial intention was to answer any concrete questions that arose when someone else put the PR together.
I put together a branch at rwinch/jeknins/tree/security that updates to the latest Spring and Spring Security. At the moment, mvn -Plight-test test passes, but a full build fails. One of the issues appears to be that there are external libraries that will need updating as well (i.e. matrix-auth). There is also some clean up that needs to be done (i.e. whitespace changes that should be removed, etc).
I'm not certain I will get time to spend on this again in the near future. Perhaps someone can take what I have put together and polish it?
PS: At this point I'm fully relying on the tests to catch any errors. it is possible there are logic errors in my changes as I went through them rather abruptly