Merge pull request #1860 from DarthSim/fix-new-model-blank-uploader

Memorize uploader instance when creating a blank uploader

lib/carrierwave/mount.rb

@@ -139,7 +139,7 @@ def mount_uploader(column, uploader=nil, options={}, &block)
       mod.class_eval <<-RUBY, __FILE__, __LINE__+1
 
         def #{column}
-          _mounter(:#{column}).uploaders[0] or _mounter(:#{column}).blank_uploader
+          _mounter(:#{column}).uploaders[0] ||= _mounter(:#{column}).blank_uploader
         end
 
         def #{column}=(new_file)

spec/mount_single_spec.rb

@@ -100,6 +100,11 @@ def rotate
         expect(@instance.image).to be_blank
       end
 
+      it "should return the same object every time when nothing has been assigned" do
+        expect(@instance).to receive(:read_uploader).with(:image).and_return(nil)
+        expect(@instance.image.object_id).to eq @instance.image.object_id
+      end
+
       it "should return a blank uploader when an empty string has been assigned" do
         expect(@instance).to receive(:read_uploader).with(:image).and_return('')
         expect(@instance.image).to be_an_instance_of(@uploader)