1 files changed, 48 insertions, 3 deletions
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index db18fb7c0f..b7cd466e13 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -131,6 +131,14 @@ module ActiveRecord
         @sanitized_conditions ||= klass.send(:sanitize_sql, options[:conditions]) if options[:conditions]
       end
 
+      # TODO: Remove these in the final patch. I am just using them for debugging etc.
+      def inspect
+        "#<#{code_name}>"
+      end
+      def code_name
+        "#{active_record.name}.#{macro} :#{name}"
+      end
+
       private
         def derive_class_name
           name.to_s.camelize
@@ -241,6 +249,10 @@ module ActiveRecord
       def through_reflection
         false
       end
+      
+      def through_reflection_chain
+        [self]
+      end
 
       def through_reflection_primary_key_name
       end
@@ -304,6 +316,16 @@ module ActiveRecord
       def belongs_to?
         macro == :belongs_to
       end
+      
+      # TODO: Remove for final patch. Just here for debugging.
+      def inspect
+        str = "#<#{code_name}, @source_reflection="
+        str << (source_reflection.respond_to?(:code_name) ? source_reflection.code_name : source_reflection.inspect)
+        str << ", @through_reflection="
+        str << (through_reflection.respond_to?(:code_name) ? through_reflection.code_name : through_reflection.inspect)
+        str << ">"
+        str
+      end
 
       private
         def derive_class_name
@@ -352,6 +374,27 @@ module ActiveRecord
       def through_reflection
         @through_reflection ||= active_record.reflect_on_association(options[:through])
       end
+      
+      # TODO: Documentation
+      def through_reflection_chain
+        @through_reflection_chain ||= begin
+          if source_reflection.through_reflection
+            # If the source reflection goes through another reflection, then the chain must start
+            # by getting us to the source reflection.
+            chain = source_reflection.through_reflection_chain
+          else
+            # If the source reflection does not go through another reflection, then we can get
+            # to this reflection directly, and so start the chain here
+            chain = [self]
+          end
+          
+          # Recursively build the rest of the chain
+          chain += through_reflection.through_reflection_chain
+          
+          # Finally return the completed chain
+          chain
+        end
+      end
 
       # Gets an array of possible <tt>:through</tt> source reflection names:
       #
@@ -378,9 +421,11 @@ module ActiveRecord
           raise HasManyThroughAssociationPolymorphicError.new(active_record.name, self, source_reflection)
         end
 
-        unless [:belongs_to, :has_many, :has_one].include?(source_reflection.macro) && source_reflection.options[:through].nil?
-          raise HasManyThroughSourceAssociationMacroError.new(self)
-        end
+        # TODO: Presumably remove the HasManyThroughSourceAssociationMacroError class and delete these lines.
+        # Think about whether there are any cases which should still be disallowed.
+        # unless [:belongs_to, :has_many, :has_one].include?(source_reflection.macro) && source_reflection.options[:through].nil?
+        #   raise HasManyThroughSourceAssociationMacroError.new(self)
+        # end
 
         check_validity_of_inverse!
       end