Sort of the opposite of
NMS-6030, if I create a user with the REST API the user is not available for login immediately after creation. If I log in to the web UI as an admin and click the edit button for the new user, then click the Finish button that's enough to make the account work. Restarting OpenNMS also makes the account work. Touching the users and groups XML files does not help.
I see that the UserRestService uses UserManager.save(OnmsUser user) rather than UserManager.saveUser(String name, User details) like all the web UI stuff does, but I hacked on UserRestService to convert the OnmsUser instance to a User instance and changed it to use saveUser but that didn't fix it. (I also added encryption to the supplied password while I was in there but I'll submit that as a separate enhancement).