[ruby/open-uri] Make URI.open pass keywords

Fixes [Bug #19238]

https://github.com/ruby/open-uri/commit/f636d01b85

lib/open-uri.rb

@@ -31,6 +31,7 @@ module URI
       super
     end
   end
+  singleton_class.send(:ruby2_keywords, :open) if respond_to?(:ruby2_keywords, true)
 end
 
 # OpenURI is an easy-to-use wrapper for Net::HTTP, Net::HTTPS and Net::FTP.

test/open-uri/test_open-uri.rb

@@ -172,6 +172,16 @@ class TestOpenURI < Test::Unit::TestCase
     assert_raise(ArgumentError) { URI.open("http://127.0.0.1/", :invalid_option=>true) {} }
   end
 
+  def test_pass_keywords
+    require 'tempfile'
+    t = Tempfile.new
+    assert_kind_of File, URI.open(Tempfile.new.path, mode: 0666)
+
+    o = Object.new
+    def o.open(foo: ) foo end
+    assert_equal 1, URI.open(o, foo: 1)
+  end
+
   def test_mode
     with_http {|srv, dr, url|
       srv.mount_proc("/mode", lambda { |req, res| res.body = "mode" } )