Fixed bug where many to one query would be unscoped

[#881 state:resolved]

lib/dm-core/query.rb

@@ -977,16 +977,15 @@ def append_condition(subject, bind_value, operator = :eql)
           subject
 
         when Associations::Relationship
-          # TODO: handle compound keys.  Consider pushing this into the adapter
-          source_key = subject.source_key.first
-          target_key = subject.target_key.first
-
           # TODO: when the bind_value is a Collection, and it is not loaded
           # then use a subquery to scope the results rather than lazy loading
           # it just to retrieve the Resource key
 
-          if (resources = Array(bind_value).select { |r| r.saved? }).any?
-            source_values = resources.map { |r| target_key.get(r) }
+          # TODO: handle compound keys.  Consider pushing this into the adapter
+          source_key = subject.source_key.first
+          target_key = subject.target_key.first
+
+          if (source_values = Array(bind_value).map { |resource| target_key.get!(resource) }.compact).any?
             append_condition(source_key, source_values, operator)
           end
 

spec/public/model/relationship_spec.rb

@@ -507,6 +507,27 @@ def n
       end
 
       supported_by :all do
+        describe 'querying for a parent resource when only the foreign key is set' do
+          before :all do
+            # create a car that would be returned if the query is not
+            # scoped properly to retrieve @car
+            Car.create
+
+            @car = Car.create
+            engine = Engine.new(:car_id => @car.id)
+
+            @return = engine.car
+          end
+
+          it 'should return a Resource' do
+            @return.should be_kind_of(DataMapper::Resource)
+          end
+
+          it 'should return expected Resource' do
+            @return.should eql(@car)
+          end
+        end
+
         describe 'querying for a parent resource' do
           before :all do
             @car = Car.create