Fix a bug when passing a method name to `:if` and `:unless` option in…

Fix a bug when passing a method name to `:if` and `:unless` option in `validates_attachment_presence`

Fixes #631

lib/paperclip.rb

@@ -385,13 +385,13 @@ module Paperclip
     # Places ActiveRecord-style validations on the presence of a file.
     # Options:
     # * +if+: A lambda or name of a method on the instance. Validation will only
-    #   be run is this lambda or method returns true.
+    #   be run if this lambda or method returns true.
     # * +unless+: Same as +if+ but validates if lambda or method returns false.
     def validates_attachment_presence name, options = {}
       message = options[:message] || :empty
       validates_each :"#{name}_file_name" do |record, attr, value|
-        if_clause_passed = options[:if].nil? || (options[:if].call(record) != false)
-        unless_clause_passed = options[:unless].nil? || (!!options[:unless].call(record) == false)
+        if_clause_passed = options[:if].nil? || (options[:if].respond_to?(:call) ? options[:if].call(record) != false : record.send(options[:if]))
+        unless_clause_passed = options[:unless].nil? || (options[:unless].respond_to?(:call) ? !!options[:unless].call(record) == false : !record.send(options[:unless]))
         if if_clause_passed && unless_clause_passed && value.blank?
           record.errors.add(name, message)
           record.errors.add("#{name}_file_name", message)

test/paperclip_test.rb

@@ -170,6 +170,7 @@ class PaperclipTest < Test::Unit::TestCase
     end
 
     context "a validation with an if guard clause" do
+      context "as a lambda" do
         setup do
           Dummy.send(:"validates_attachment_presence", :avatar, :if => lambda{|i| i.foo })
           @dummy = Dummy.new
@@ -187,7 +188,27 @@ class PaperclipTest < Test::Unit::TestCase
         end
       end
 
+      context "as a method name" do
+        setup do
+          Dummy.send(:"validates_attachment_presence", :avatar, :if => :foo)
+          @dummy = Dummy.new
+          @dummy.stubs(:avatar_file_name).returns(nil)
+        end
+
+        should "attempt validation if the guard returns true" do
+          @dummy.expects(:foo).returns(true)
+          assert ! @dummy.valid?
+        end
+
+        should "not attempt validation if the guard returns false" do
+          @dummy.expects(:foo).returns(false)
+          assert @dummy.valid?
+        end
+      end
+    end
+
     context "a validation with an unless guard clause" do
+      context "as a lambda" do
         setup do
           Dummy.send(:"validates_attachment_presence", :avatar, :unless => lambda{|i| i.foo })
           @dummy = Dummy.new
@@ -205,6 +226,25 @@ class PaperclipTest < Test::Unit::TestCase
         end
       end
 
+      context "as a method name" do
+        setup do
+          Dummy.send(:"validates_attachment_presence", :avatar, :unless => :foo)
+          @dummy = Dummy.new
+          @dummy.stubs(:avatar_file_name).returns(nil)
+        end
+
+        should "attempt validation if the guard returns true" do
+          @dummy.expects(:foo).returns(false)
+          assert ! @dummy.valid?
+        end
+
+        should "not attempt validation if the guard returns false" do
+          @dummy.expects(:foo).returns(true)
+          assert @dummy.valid?
+        end
+      end
+    end
+
     should "not have Attachment in the ActiveRecord::Base namespace" do
       assert_raises(NameError) do
         ActiveRecord::Base::Attachment