Only use Tempfile subclass in 1.8.6 and below. Fixes #278.

lib/paperclip/iostream.rb

@@ -5,7 +5,7 @@ module IOStream
   # Returns a Tempfile containing the contents of the readable object.
   def to_tempfile
     name = respond_to?(:original_filename) ? original_filename : (respond_to?(:path) ? path : "stream")
-    tempfile = Paperclip::Tempfile.new("stream" + File.extname(name))
+    tempfile = Paperclip::Tempfile.new(["stream", File.extname(name)])
     tempfile.binmode
     self.stream_to(tempfile)
   end

lib/paperclip/processor.rb

@@ -40,10 +40,19 @@ module Paperclip
   # on this blog post:
   # http://marsorange.com/archives/of-mogrify-ruby-tempfile-dynamic-class-definitions
   class Tempfile < ::Tempfile
-    # Replaces Tempfile's +make_tmpname+ with one that honors file extensions.
-    def make_tmpname(basename, n)
-      extension = File.extname(basename)
-      sprintf("%s,%d,%d%s", File.basename(basename, extension), $$, n.to_i, extension)
+    # This is Ruby 1.8.7's implementation.
+    if RUBY_VERSION <= "1.8.6"
+      def make_tmpname(basename, n)
+        case basename
+        when Array
+          prefix, suffix = *basename
+        else
+          prefix, suffix = basename, ''
+        end
+
+        t = time.now.strftime("%y%m%d")
+        path = "#{prefix}#{t}-#{$$}-#{rand(0x100000000).to_s(36)}-#{n}#{suffix}"
+      end
     end
   end
 end

lib/paperclip/storage/s3.rb

@@ -127,7 +127,10 @@ module Paperclip
       # style, in the format most representative of the current storage.
       def to_file style = default_style
         return @queued_for_write[style] if @queued_for_write[style]
-        file = Tempfile.new(path(style))
+        filename = path(style).split(".")
+        extname  = File.extname(filename)
+        basename = File.basename(filename, extname)
+        file = Tempfile.new(basename, extname)
         file.write(AWS::S3::S3Object.value(path(style), bucket_name))
         file.rewind
         return file

lib/paperclip/thumbnail.rb

@@ -45,7 +45,7 @@ module Paperclip
     # that contains the new image.
     def make
       src = @file
-      dst = Tempfile.new([@basename, @format].compact.join("."))
+      dst = Tempfile.new([@basename, @format ? ".#{@format}" : ''])
       dst.binmode
 
       begin

test/thumbnail_test.rb

@@ -4,10 +4,11 @@ class ThumbnailTest < Test::Unit::TestCase
 
   context "A Paperclip Tempfile" do
     setup do
-      @tempfile = Paperclip::Tempfile.new("file.jpg")
+      @tempfile = Paperclip::Tempfile.new(["file", ".jpg"])
     end
 
     should "have its path contain a real extension" do
+      p @tempfile.path
       assert_equal ".jpg", File.extname(@tempfile.path)
     end