replica_set.rb in mongo-2.6.2

- old
+ new

@@ -211,10 +211,16 @@
                 description.hosts.empty? ||
                   !member_of_this_set?(description))
         end
 
         # Whether a specific server in the cluster can be removed, given a description.
+        # As described in the SDAM spec, a server should be removed if the server's
+        # address does not match the "me" field of the isMaster response, if the server
+        # has a different replica set name, or if an isMaster response from the primary
+        # does not contain the server's address in the list of known hosts. Note that as
+        # described by the spec, a server determined to be of type Unknown from its
+        # isMaster response is NOT removed from the topology.
         #
         # @example Check if a specific server can be removed from the cluster.
         #   topology.remove_server?(description, server)
         #
         # @param [ Mongo::Server::Description ] description The description.
@@ -222,12 +228,14 @@
         #
         # @return [ true, false ] Whether the server can be removed from the cluster.
         #
         # @since 2.0.6
         def remove_server?(description, server)
+          ((server.address == description.address) && description.me_mismatch?) ||
           remove_self?(description, server) ||
             (member_of_this_set?(description) &&
+                description.server_type == :primary &&
                 !description.servers.empty? &&
                   !description.lists_server?(server))
         end
 
         # A replica set topology is not sharded.
@@ -314,13 +322,17 @@
         def member_of_this_set?(description)
           description.replica_set_member? &&
             description.replica_set_name == replica_set_name
         end
 
+        # As described by the SDAM spec, a server should be removed from the
+        # topology upon receiving its isMaster response if no error occurred
+        # and replica set name does not match that of the topology.
         def remove_self?(description, server)
-          !member_of_this_set?(description) &&
-            description.is_server?(server) &&
-              !description.ghost?
+          !description.unknown? &&
+            !member_of_this_set?(description) &&
+              description.is_server?(server) &&
+                !description.ghost?
         end
       end
     end
   end
 end