[PERSISTENCE][FIX] Changing instance properties should not affect pro…

…perty default

Hash and Array... were passed to property as reference, not object

lib/tire/model/persistence/attributes.rb

@@ -27,7 +27,7 @@ def property(name, options = {})
 
             # Define attribute reader:
             define_method("#{name}") do
-              instance_variable_get(:"@#{name}") || self.class.property_defaults[name.to_sym]
+              instance_variable_get(:"@#{name}")
             end
 
             # Define attribute writer:
@@ -82,7 +82,14 @@ module InstanceMethods
           attr_accessor :id
 
           def initialize(attributes={})
-            __update_attributes(attributes)
+            # Make a copy of objects in the property defaults hash, so default values such as `[]` or `{ foo: [] }` are left intact
+            property_defaults = self.class.property_defaults.inject({}) do |hash, item|
+              key, value = item
+              hash[key.to_s] = value.class.respond_to?(:new) ? value.clone : value
+              hash
+            end
+
+            __update_attributes(property_defaults.merge(attributes))
           end
 
           def attributes

test/models/persistent_article_with_defaults.rb

@@ -6,5 +6,6 @@ class PersistentArticleWithDefaults
   property :published_on
   property :tags,   :default => []
   property :hidden, :default => false
+  property :options,  :default => {:switches => []}
 
 end

test/unit/model_persistence_test.rb

@@ -201,6 +201,16 @@ class << a
             assert_equal false, article.hidden
           end
 
+          should "not affect default value" do
+            article = PersistentArticleWithDefaults.new :title => 'Test'
+            article.tags << "ruby"
+
+            article.options[:switches] << "switch_1"
+
+            assert_equal [], PersistentArticleWithDefaults.new.tags
+            assert_equal [], PersistentArticleWithDefaults.new.options[:switches]
+           end
+
           should "have query method for attribute" do
             assert_equal true, @article.title?
           end