Fix inconsistencies with Dash defaults

The normal behavior of Dash with respect to property defaults differed
from the behavior of a Dash/Trash with IgnoreUndeclared mixed in. This
is because some situations called the defaults and some did not.

This change normalizes the behavior so that all situations where the
defaults should be used to override unset values behave consistently,
as well as all situations where the default should not override a `nil`
value.

1 files changed, 9 insertions, 16 deletions

diff --git a/lib/hashie/dash.rb b/lib/hashie/dash.rb
index 460790b..785d94d 100644
--- a/lib/hashie/dash.rb
+++ b/lib/hashie/dash.rb
@@ -104,19 +104,6 @@ module Hashie
     def initialize(attributes = {}, &block)
       super(&block)
 
-      self.class.defaults.each_pair do |prop, value|
-        self[prop] = begin
-          val = value.dup
-          if val.is_a?(Proc)
-            val.arity == 1 ? val.call(self) : val.call
-          else
-            val
-          end
-        rescue TypeError
-          value
-        end
-      end
-
       initialize_attributes(attributes)
       assert_required_attributes_set!
     end
@@ -173,13 +160,19 @@ module Hashie
       update_attributes(attributes)
 
       self.class.defaults.each_pair do |prop, value|
-        next unless self[prop].nil?
+        next unless fetch(prop, nil).nil?
         self[prop] = begin
-          value.dup
+          val = value.dup
+          if val.is_a?(Proc)
+            val.arity == 1 ? val.call(self) : val.call
+          else
+            val
+          end
         rescue TypeError
           value
         end
       end
+
       assert_required_attributes_set!
     end
 
@@ -189,7 +182,7 @@ module Hashie
       return unless attributes
 
       cleaned_attributes = attributes.reject { |_attr, value| value.nil? }
-      update_attributes(cleaned_attributes)
+      update_attributes!(cleaned_attributes)
     end
 
     def update_attributes(attributes)