Adjusting the methods that dealt with the encoding/decoding data for attributes in ActiveRecord's :serialized_attributes hash so that it will fall back on YAML as the default serializer. Close #197

CHANGELOG.md

@@ -1,5 +1,8 @@
 ## 2.7.1 (Unreleased)
 
+  - [#197](https://github.com/airblade/paper_trail/issues/197) - PaperTrail now falls back on using YAML for serialization of
+    serialized model attributes for storage in the `object` and `object_changes` columns in the `Version` table. This fixes
+    compatibility for `Rails 3.0.x` for projects that employ the `serialize` declaration on a model.
   - [#194](https://github.com/airblade/paper_trail/issues/194) - A JSON serializer is now included in the gem.
   - [#192](https://github.com/airblade/paper_trail/pull/192) - `object_changes` should store serialized representation of serialized
     attributes for `create` actions (in addition to `update` actions, which had already been patched by
@@ -14,7 +17,7 @@
   - [#183](https://github.com/airblade/paper_trail/pull/183) - Fully qualify the `Version` class to help prevent
     namespace resolution errors within other gems / plugins.
   - [#180](https://github.com/airblade/paper_trail/pull/180) - Store serialized representation of serialized attributes
-    on the `object` and `object_changes` column in the `Version` table.
+    on the `object` and `object_changes` columns in the `Version` table.
   - [#164](https://github.com/airblade/paper_trail/pull/164) - Allow usage of custom serializer for storage of object attributes.
 
 ## 2.6.4

lib/paper_trail/has_paper_trail.rb

@@ -84,13 +84,19 @@ module PaperTrail
       # Used for Version#object attribute
       def serialize_attributes_for_paper_trail(attributes)
         serialized_attributes.each do |key, coder|
-          attributes[key] = coder.dump(attributes[key]) if attributes.key?(key)
+          if attributes.key?(key)
+            coder = PaperTrail::Serializers::Yaml unless coder.respond_to?(:dump) # Rails 3.0.x's default serializers don't have a `dump` method
+            attributes[key] = coder.dump(attributes[key])
+          end
         end
       end
 
       def unserialize_attributes_for_paper_trail(attributes)
         serialized_attributes.each do |key, coder|
-          attributes[key] = coder.load(attributes[key]) if attributes.key?(key)
+          if attributes.key?(key)
+            coder = PaperTrail::Serializers::Yaml unless coder.respond_to?(:dump)
+            attributes[key] = coder.load(attributes[key])
+          end
         end
       end
 
@@ -98,6 +104,7 @@ module PaperTrail
       def serialize_attribute_changes(changes)
         serialized_attributes.each do |key, coder|
           if changes.key?(key)
+            coder = PaperTrail::Serializers::Yaml unless coder.respond_to?(:dump) # Rails 3.0.x's default serializers don't have a `dump` method
             old_value, new_value = changes[key]
             changes[key] = [coder.dump(old_value),
                             coder.dump(new_value)]
@@ -108,6 +115,7 @@ module PaperTrail
       def unserialize_attribute_changes(changes)
         serialized_attributes.each do |key, coder|
           if changes.key?(key)
+            coder = PaperTrail::Serializers::Yaml unless coder.respond_to?(:dump)
             old_value, new_value = changes[key]
             changes[key] = [coder.load(old_value),
                             coder.load(new_value)]