A real check for infinite loops in the :url interpolation.

lib/paperclip/interpolations.rb

@@ -42,7 +42,7 @@ def filename attachment, style_name
     # contains ":url" to prevent infinite recursion. This interpolation
     # is used in the default :path to ease default specifications.
     def url attachment, style_name
-      raise InfiniteInterpolationError if attachment.options[:url].include?(":url")
+      raise InfiniteInterpolationError if caller.any?{|b| b.index("#{__FILE__}:#{__LINE__ + 1}") }
       attachment.url(style_name, false)
     end
 

lib/paperclip/storage.rb

@@ -144,7 +144,6 @@ def self.extended base
           @s3_headers     = @options[:s3_headers]     || {}
           @s3_host_alias  = @options[:s3_host_alias]
           unless @url.to_s.match(/^:s3.*url$/)
-            @path         = @url
             @url          = ":s3_path_url"
           end
           AWS::S3::Base.establish_connection!( @s3_options.merge(

test/interpolations_test.rb

@@ -82,14 +82,17 @@ class InterpolationsTest < Test::Unit::TestCase
 
   should "reinterpolate :url" do
     attachment = mock
-    attachment.expects(:options).returns({:url => ":id"})
     attachment.expects(:url).with(:style, false).returns("1234")
     assert_equal "1234", Paperclip::Interpolations.url(attachment, :style)
   end
 
   should "raise if infinite loop detcted reinterpolating :url" do
-    attachment = mock
-    attachment.expects(:options).returns({:url => ":url"})
+    attachment = Object.new
+    class << attachment
+      def url(*args)
+        Paperclip::Interpolations.url(self, :style)
+      end
+    end
     assert_raises(Paperclip::InfiniteInterpolationError){ Paperclip::Interpolations.url(attachment, :style) }
   end