Yes, it is definitively nicer to have others to work with--I've had a lot of lone wolf years on Liquibase, so all the more reason to work together.
LB4 has some significant changes and a much nicer codebase, but it is definitely still pre-alpha. Pieces are getting to be in place, but I'm stuck in the middle of the massive work of refactoring and testing all the Change (called Action) implementations. If you are looking for something useful now, LB4 is not the place to look...
That being said, I can watch your changes with an eye to the plans for LB4. You are right that 3.x is not a dead-end. My plan has been to to keep 3.x maintained for the foreseeable future but limit the changes to bugfixes and feature improvements that do not require extensive changes to the codebase. Changes in the 4.0 codebase will be backported back as it makes sense as well, but I would like to keep at Java 7.x support in the 3.x codebase which can limit some of the code sharing. You'd be surprised how many people are still on Java 7 and I don't want to cut them out of the maintained codebase.
I understand your need for to get something out right away for use and an independent project makes sense for that, but from an end-user-confusion standpoint, I think it would be nice to see if we could fold your changes into the main Liquibase codeline as soon as we can. If you have done the hard work of integrating and testing a large number of the pull requests that is hugely helpful and I'd definitely like to take advantage of that.
I'll take a look at your fork tomorrow and the changes you have made. Perhaps the majority of it can be brought in directly? I'll see what they look like. It is hard to break existing work into separate pull requests, but I can probably just look at the branch diffs as a whole.
Great to see you have working integration tests for the OSS databases. I'll definitely look at that. Sonar would also be helpful to use, is that set up within your CircleCI config currently?
My pressing deadlines actually ended a week or so ago and I had already started to return to Liquibase proper, but on the 4.0 side initially. However, if there is a pressing need and offers to help on the 3.x side I will gladly look at that instead.
Nathan