Added Property#to_child_key.

The method by default returns the property class but there might be
some exceptions like Serial, which returns Integer. This is required
so that custom properties that are used as PKs can work correctly with
ManyToOne assocations - UUID from dm-types is a good example.

[#1348 status:resolved]

lib/dm-core/associations/many_to_one.rb

@@ -55,8 +55,7 @@ def child_key
             properties[property_name] || begin
               # create the property within the correct repository
               DataMapper.repository(repository_name) do
-                type = parent_property.send(parent_property.type == DataMapper::Property::Boolean ? :type : :primitive)
-                model.property(property_name, type, child_key_options(parent_property))
+                model.property(property_name, parent_property.to_child_key, child_key_options(parent_property))
               end
             end
           end

lib/dm-core/property/object.rb

@@ -27,6 +27,11 @@ def load(value)
             value
           end
       end
+
+      # @api private
+      def to_child_key
+        self.class
+      end
     end
   end
 end

lib/dm-core/property/serial.rb

@@ -3,6 +3,11 @@ class Property
     class Serial < Integer
       serial    true
       min       1
+
+      # @api private
+      def to_child_key
+        Property::Integer
+      end
     end # class Text
   end # module Property
 end # module DataMapper

spec/public/associations/many_to_one_with_custom_fk_spec.rb

@@ -0,0 +1,49 @@
+require File.expand_path(File.join(File.dirname(__FILE__), '..', '..', 'spec_helper'))
+
+# TODO: combine this into many_to_one_spec.rb
+
+describe 'Many to One Associations when foreign key is a custom property' do
+  before :all do
+    class ::CustomPK < DataMapper::Property::String
+      key true
+    end
+
+    class ::Animal
+      include DataMapper::Resource
+
+      property :id,   Serial
+      property :name, String
+
+      belongs_to :zoo
+    end
+
+    class ::Zoo
+      include DataMapper::Resource
+
+      property :id, ::CustomPK
+
+      has n, :animals
+    end
+
+    DataMapper.finalize
+  end
+
+  supported_by :all do
+    before :all do
+      @zoo    = Zoo.create(:id => 'foo')
+      @animal = @zoo.animals.create(:name => 'marty')
+    end
+
+    it 'should have FK of the same property type as zoo PK' do
+      Animal.properties[:zoo_id].class.should be(Zoo.properties[:id].class)
+    end
+
+    it 'should be able to access parent' do
+      @animal.zoo.should == @zoo
+    end
+
+    it 'should be able to access the children' do
+      @zoo.animals.should == [ @animal ]
+    end
+  end
+end

spec/semipublic/resource/state/dirty_spec.rb

@@ -51,7 +51,7 @@ class ::Author
         it 'should set the child key if the parent key changes' do
           original_id = @parent.id
           @parent.update(:id => 42).should be(true)
-          method(:subject).should change(@resource, :parent_id).from(original_id.to_s).to('42')
+          method(:subject).should change(@resource, :parent_id).from(original_id).to(42)
         end
 
         it 'should update the resource' do