The problem:
* Node that is Up joins a cluster and becomes Joining in that cluster
* The joining node receives gossip, which results in conflict,
merge results in Up
* It became Up in the new cluster without passing the ordinary leader
action to move it to Up
The solution:
* Change priority order of Up and Joining so that Joining is used when
merging
- introducing RepointableActorRef, which starts out with an
UnstartedActorCell which can cheaply be created; the Supervise()
message will trigger child.activate() in the supervisor, which means
that the actual creation (now with normal ActorCell) happens exactly
in the right place and with the right semantics. Messages which were
enqueued to the dummy cell are transferred atomically into the
ActorCell (using normal .tell()), so message sends keep working
exactly as they used to
- this enables getting rid of the brittle synchronization around
RoutedActorRef by replacing that one with a RepointableActorRef
subclass which creates RoutedActorCells upon activate(), with the nice
benefit that there is no hurry then to get it right because the new
cell is constructed “on the side”
misc fixes:
- InvalidMessageException is now actually enforced when trying to send
“null”
- Mailboxes may be created without having an ActorCell, which can come
in handy later, because the cell is only needed when this mailbox is
going to be scheduled on some executor
- remove occurrences of Props(), which is equivalent to Props[Nothing],
which is equivalent to «bug»
- add test case which verifies that context.actorOf is still synchronous
- plus all the stuff I have forgotten.
* Merge unreachable using highestPriorityOf
* Avoid merge result in node existing in both members and unreachable
* Fix joining only allowed when !alreadyMember && !isUnreachable (non Down)
* Fix filter bug of unreachable in downing and leaderActions
* Minor cleanups
* All members must be in seen table for convergence
* Added extra debug logging due to convergence issues
* Enabled test of convergence for node joining singleton
cluster
