map_reduce.rb in mongo-2.17.0

- old
+ new

@@ -113,10 +113,12 @@
         def initialize(view, map, reduce, options = {})
           @view = view
           @map_function = map.dup.freeze
           @reduce_function = reduce.dup.freeze
           @options = BSON::Document.new(options).freeze
+
+          client.log_warn('The map_reduce operation is deprecated, please use the aggregation pipeline instead')
         end
 
         # Set or get the jsMode flag for the operation.
         #
         # @example Set js mode for the operation.
@@ -246,23 +248,10 @@
         def new(options)
           MapReduce.new(view, map_function, reduce_function, options)
         end
 
         def initial_query_op(session)
-          spec = map_reduce_spec(session)
-          # Read preference isn't simply passed in the command payload
-          # (it may need to be converted to wire protocol flags).
-          # Passing it in command payload produces errors on at least
-          # 5.0 mongoses.
-          # In the future map_reduce_command should remove :read
-          # from its return value, however we cannot do this right now
-          # due to Mongoid 7 relying on :read being returned as part of
-          # the command - see RUBY-2932.
-          # Delete :read here for now because it cannot be sent to mongos this way.
-          spec = spec.dup
-          spec[:selector] = spec[:selector].dup
-          spec[:selector].delete(:read)
-          Operation::MapReduce.new(spec)
+          Operation::MapReduce.new(map_reduce_spec(session))
         end
 
         def valid_server?(server)
           if secondary_ok?
             true