Cache parent record when calling build on a has_many/one association

lib/her/model/associations/association.rb

@@ -68,6 +68,12 @@ def build_association_path(code)
         # @private
         def build_with_inverse(attributes = {})
           @klass.build(attributes.merge(:"#{@parent.singularized_resource_name}_id" => @parent.id)).tap do |resource|
+            if @opts[:inverse_of]
+              resource.send "#{@opts[:inverse_of]}=", @parent
+            elsif @klass.associations[:belongs_to].any? { |a| a[:name].to_s == @parent.singularized_resource_name.to_s }
+              resource.send "#{@parent.singularized_resource_name}=", @parent
+            end
+
             begin
               resource.request_path
             rescue Her::Errors::PathError => e

spec/model/associations_spec.rb

@@ -495,6 +495,7 @@ def present?
       end
       spawn_model "Foo::Comment" do
         collection_path "/users/:user_id/comments"
+        belongs_to :user
         has_many :likes
       end
       spawn_model "Foo::User" do
@@ -509,6 +510,12 @@ def present?
         expect(@comment.user_id).to eq(10)
       end
 
+      it "caches the parent record" do
+        @user = Foo::User.new(id: 10)
+        @comment = @user.comments.build
+        expect(@comment.user.object_id).to eq @user.object_id
+      end
+
       it "uses nested path parameters from the parent" do
         @like = Foo::User.new(:id => 10).comments.build(:id => 20).likes.build
         @like.request_path.should == "/users/10/comments/20/likes"