* tool/downloader.rb (RubyGems.download): Don't download gem if the

version is already downloaded. A gem file is versioned and
  it must be identical if the version is the same.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48494 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Wed Nov 19 18:12:17 2014  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* tool/downloader.rb (RubyGems.download): Don't download gem if the
+	  version is already downloaded. A gem file is versioned and
+	  it must be identical if the version is the same.
+
 Wed Nov 19 17:59:25 2014  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* common.mk (ext/ripper/ripper.c): pass build directory as VPATH.

tool/downloader.rb

@@ -9,6 +9,10 @@ class Downloader
 
   class RubyGems < self
     def self.download(name, *rest)
+      if File.exist?(name)
+        $stdout.puts "#{name} already exists"
+        return
+      end
       super("https://rubygems.org/downloads/#{name}", name, *rest)
     end
   end