Only nil and valid files clobber the existing attachment.

git-svn-id: https://svn.thoughtbot.com/plugins/paperclip/trunk@431 7bbfaf0e-4d1d-0410-9690-a8bb5f8ef2aa

lib/paperclip/attachment.rb

@@ -3,6 +3,17 @@ module Paperclip
   # deletes when the model is destroyed, and processes the file upon assignment.
   class Attachment
     
+    def self.defaults
+      @defaults ||= {
+        :url => "/:attachment/:id/:style/:basename.:extension",
+        :path => ":rails_root/public/:attachment/:id/:style/:basename.:extension",
+        :styles => {},
+        :default_url => "/:attachment/:style/missing.png",
+        :default_style => :original,
+        :validations => []
+      }
+    end
+
     attr_reader :name, :instance, :file, :styles, :default_style
 
     # Creates an Attachment object. +name+ is the name of the attachment, +instance+ is the
@@ -11,6 +22,9 @@ module Paperclip
     def initialize name, instance, options
       @name              = name
       @instance          = instance
+
+      # options = options.merge(self.class.defaults)
+
       @url               = options[:url]           || 
                            "/:attachment/:id/:style/:basename.:extension"
       @path              = options[:path]          || 
@@ -34,11 +48,13 @@ module Paperclip
     # assigns attributes, processes the file, and runs validations. It also queues up
     # the previous file for deletion, to be flushed away on #save of its host.
     def assign uploaded_file
+      return nil unless valid_file?(uploaded_file) || uploaded_file.nil?
+
       queue_existing_for_delete
       @errors            = []
       @validation_errors = nil 
 
-      return nil unless valid_file?(uploaded_file)
+      return nil if uploaded_file.nil?
 
       @file                               = uploaded_file.to_tempfile
       @instance[:"#{@name}_file_name"]    = uploaded_file.original_filename

test/test_attachment.rb

@@ -5,6 +5,49 @@ class Dummy
 end
 
 class AttachmentTest < Test::Unit::TestCase
+#  context "Attachment defaults" do
+#    setup do
+#      @old_defaults = Paperclip::Attachment.defaults
+#      @new_defaults = @old_defaults.merge({
+#        :path => "argle/bargle",
+#        :url => "fooferon",
+#        :default_url => "not here.png"
+#      })
+#    end
+#
+#    should "be overrideable" do
+#      Paperclip::Attachment.defaults.merge!(@new_defaults)
+#      @new_defaults.keys.each do |key|
+#        assert_equal @new_defaults[key], Paperclip::Attachment.defaults[key]
+#      end
+#    end
+#
+#    context "on an Attachment" do
+#      setup do
+#        @attachment = Dummy.new
+#      end
+#
+#      should "be the defaults" do
+#        @old_defaults.keys.each do |key|
+#          assert_equal @old_defaults[key], @attachment.instance_variable_get("@#{key}"), key
+#        end
+#      end
+#
+#      context "when redefined" do
+#        setup do
+#          Paperclip::Attachment.defaults.merge!(@new_defaults)
+#          @attachment = Dummy.new
+#        end
+#
+#        should "be the new defaults" do
+#          @new_defaults.keys.each do |key|
+#            assert_equal @new_defaults[key], @attachment.instance_variable_get("@#{key}"), key
+#          end
+#        end
+#      end
+#    end
+#  end
+
   context "An attachment" do
     setup do
       @default_options = {

test/test_integration.rb

@@ -38,6 +38,15 @@ class PaperclipTest < Test::Unit::TestCase
       assert_equal "100x15", `identify -format "%wx%h" #{@d2.avatar.to_io(:medium).path}`.chomp
       assert_equal "32x32",  `identify -format "%wx%h" #{@d2.avatar.to_io(:thumb).path}`.chomp
 
+      @dummy.avatar = "not a valid file but not nil"
+      assert_equal File.basename(@file.path), @dummy.avatar_file_name
+      assert @dummy.valid?
+      assert @dummy.save
+
+      saved_paths.each do |p|
+        assert File.exists?(p)
+      end
+
       @dummy.avatar = nil
       assert_nil @dummy.avatar_file_name
       assert @dummy.valid?