don't raise an error if an uploaded file has no original filename

Browsers tend to send a filename, but some API clients don't.

fixes CNVS-4233

test plan: do a multipart file upload to an api endpoint, such as a sis
api, and leave out the filename=/original/filename component of the
parameter. the upload should still be accepted and no error raised.

Change-Id: I9be8d425693cfb9d8d44644e57358f5dc9cee4c1
Reviewed-on: https://gerrit.instructure.com/18114
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Reviewed-by: Jacob Fugal <jacob@instructure.com>
QA-Review: Clare Hetherington <clare@instructure.com>

config/initializers/ruby_version_compat.rb

@@ -98,7 +98,7 @@ else
           o.force_encoding(Encoding::UTF_8)
           raise ActionController::InvalidByteSequenceErrorFromParams unless o.valid_encoding?
         end
-        if o.respond_to?(:original_filename)
+        if o.respond_to?(:original_filename) && o.original_filename
           o.original_filename.force_encoding(Encoding::UTF_8)
           raise ActionController::InvalidByteSequenceErrorFromParams unless o.original_filename.valid_encoding?
         end

spec/initializers/ruby_version_compat_spec.rb

@@ -20,4 +20,16 @@ describe 'ruby_version_compat' do
       output.should == ['', '']
     end
   end
+
+  describe "force_utf8_params" do
+    it "should allow null filenames through" do
+      testfile = ActionController::TestUploadedFile.new(File.join(File.dirname(__FILE__), "/../fixtures/scribd_docs/txt.txt"), "text/plain", true)
+      testfile.instance_variable_set(:@original_filename, nil)
+      controller = ApplicationController.new
+      controller.stubs(:params).returns({ :upload => { :file1 => testfile } })
+      controller.stubs(:request).returns(mock(:path => "/upload"))
+      expect { controller.force_utf8_params() }.to_not raise_error
+      testfile.original_filename.should be_nil
+    end
+  end
 end