worker: prevent deadlock by flooding worker.Messages channel

Send to worker.Messages in goroutine to prevent deadlocks: the UI can
fill the worker.Actions channel. The worker can generate more than one
Message per action, and if it generates enough to fill the
worker.Messages channel from a single message while the worker.Actions
channel is full, a deadlock occurs.

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Robin Jarry <robin@jarry.cc>

worker/types/worker.go

@@ -64,7 +64,10 @@ func (worker *Worker) PostMessage(msg WorkerMessage,
 	} else {
 		logging.Debugf("PostMessage %T", msg)
 	}
-	worker.Messages <- msg
+	// This one needs to be in a separate goroutine to prevent deadlocks
+	go func() {
+		worker.Messages <- msg
+	}()
 
 	if cb != nil {
 		worker.messageCallbacks[msg.getId()] = cb