Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

I don't think we need this. We do not offer BWC guarantees with pre-releases, we can skip to "5.99.99" and master will do the right thing against the 6.0 branch here (and against 6.0.x GA releases).

@jasontedor Thanks for your comments. I'll close this. I have a question is I want to skip - 6.0.0-rc1. And I tried both 5.99.99 and 5.6.3, none of them can skip. What version should I use ? Thanks in advance.

I'm not sure what you mean. When you run BWC tests they run against 6.0 in the elastic/elasticsearch repo. That branch does not have your change so I would expect any BWC tests expecting this code to be in 6.0 to fail. Instead, you have to backport your change to 6.0 and 6.x and push it to your remote. Then you can run BWC tests against your remote with -Dtests.bwc.remote=liketic.

That said, I'm not sure if that change that you're referencing should be backported to 6.0 and 6.x. I think master only is fine for this one.

I appreciate the work that you're doing here, thanks for contributing.

@liketic I commented on your original PR, as your change will not be backported, you need to skip up to 6.99.99, as any 6.x version will return 500 instead of 400 as a response code. That should work. And like Jason said, this PR is not needed, sorry for misleading you at first. Closing this one.