Write concern should not have nil or extra values

RUBY-740

Author: gjmurakami-10gen

lib/mongo/functional/uri_parser.rb

@@ -234,12 +234,12 @@ def connection_options
         warn "Using wtimeout in a URI is deprecated, please use wtimeoutMS. It will be removed in v2.0."
         opts[:wtimeout] = @wtimeout
       end
-      opts[:wtimeout] = @wtimeoutms
+      opts[:wtimeout] = @wtimeoutms if @wtimeoutms
 
       opts[:w]     = 1 if @safe
       opts[:w]     = @w if @w
-      opts[:j]     = @journal
-      opts[:fsync] = @fsync
+      opts[:j]     = @journal if @journal
+      opts[:fsync] = @fsync if @fsync
 
       opts[:connect_timeout] = @connecttimeoutms if @connecttimeoutms
       opts[:op_timeout]      = @sockettimeoutms if @sockettimeoutms
@@ -260,7 +260,7 @@ def connection_options
 
       opts[:db_name] = @db_name if @db_name
       opts[:auths]   = @auths if @auths
-      opts[:ssl]     = @ssl
+      opts[:ssl]     = @ssl if @ssl
       opts[:connect] = connect?
 
       opts

lib/mongo/functional/write_concern.rb

@@ -14,6 +14,8 @@
 
 module Mongo
   module WriteConcern
+    VALID_KEYS = [:w, :j, :fsync, :wtimeout]
+    DEFAULT_WRITE_CONCERN = {:w => 1}
 
     attr_reader :legacy_write_concern
 
@@ -44,14 +46,9 @@ def write_concern_from_legacy(opts)
     # todo: throw exception for conflicting write concern options
     def get_write_concern(opts, parent=nil)
       write_concern_from_legacy(opts) if opts.key?(:safe) || legacy_write_concern
-      write_concern = {
-        :w        => 1,
-        :j        => false,
-        :fsync    => false,
-        :wtimeout => nil
-      }
+      write_concern = DEFAULT_WRITE_CONCERN.dup
       write_concern.merge!(parent.write_concern) if parent
-      write_concern.merge!(opts.reject {|k,v| !write_concern.keys.include?(k)})
+      write_concern.merge!(opts.reject {|k,v| !VALID_KEYS.include?(k)})
       write_concern[:w] = write_concern[:w].to_s if write_concern[:w].is_a?(Symbol)
       write_concern
     end

test/functional/client_test.rb

@@ -144,6 +144,20 @@ def test_db_from_uri_from_string_param_no_db_name
     assert_equal db.name, MongoClient::DEFAULT_DB_NAME
   end
 
+  def test_from_uri_write_concern
+    con = MongoClient.from_uri("mongodb://#{host_port}")
+    db = con.db
+    coll = db.collection('from-uri-test')
+    assert_equal BSON::ObjectId, coll.insert({'a' => 1}).class
+    [con, db, coll].each do |component|
+      component.write_concern.each do |key,value|
+        assert_not_nil(value, "component #{component.class.inspect} should not have write concern #{key.inspect} field with nil value")
+      end
+    end
+    assert_equal({:w => 1}, con.write_concern, "write concern should not have extra pairs that were not specified by the user")
+    assert_equal({:w => 1}, db.write_concern, "write concern should not have extra pairs that were not specified by the user")
+    assert_equal({:w => 1}, coll.write_concern, "write concern should not have extra pairs that were not specified by the user")
+  end
 
   def test_server_version
     assert_match(/\d\.\d+(\.\d+)?/, @client.server_version.to_s)