Here's a quick hack at a patch that does this. It makes me quite nervous. It looks remarkably like some of our test code, creating a temporary directory, copying the conf directory over, and then trying to load it. If you navigate away from the edit page, it loses any changes you've made.
It also takes a while longer, and will take even longer from ZooKeeper. Do we really want to bring the conf directory down from ZK, test it, and throw it away? Or is there a better way?
It has to clean up after itself by doing a FileUtils.deleteDirectory().
I've walked through it by hand and modified one of the local filesystem tests to try it and it appears to work.
Stefan Matheis (steffkes) The response returned will now have an error in it, but that's not displayed. This is a marker, I'm not sure whether we want to go forward with this or not. And if an error is returned the progress indicator on the save button never stops.
Mark Miller is this anything like what you had in mind?
NOTE: I need to clean it up, but another instance of throwing something up that's not ready to see what people think.
Still to do is the ZooKeeper version.