Fix OpenAPI nullable properties

lib/swagger_yard/openapi.rb

@@ -70,6 +70,16 @@ def response(resp, op)
       end
     end
 
+    def property(prop)
+      prop.type.schema_with(model_path: model_path).tap do |h|
+        unless h['$ref']
+          h["description"] = prop.description if prop.description && !prop.description.strip.empty?
+          h["nullable"] = true if prop.nullable
+          h["example"] = prop.example if prop.example
+        end
+      end
+    end
+
     def security_defs(security_objects)
       defs = super
       Hash[defs.map do |name, d|

spec/lib/swagger_yard/openapi_spec.rb

@@ -225,6 +225,31 @@
 
   end
 
+  context "models" do
+    let(:model) { SwaggerYard::Model.from_yard_object(yard_class('MyModel', content)) }
+    let(:spec) { stub(path_objects: SwaggerYard::Paths.new([]), tag_objects: [],
+                      security_objects: [], model_objects: { model.id => model }) }
+
+    subject { described_class.new(spec).to_h["components"]["schemas"] }
+
+    context 'nullables' do
+      subject { super()['MyModel']['properties'] }
+
+      context "with a nullable flag" do
+        let(:content) { ['@model MyModel', '@property name(nullable) [string]  Name'] }
+
+        its(['name', 'type'])     { is_expected.to eq('string') }
+        its(['name', 'nullable']) { is_expected.to eq(true) }
+      end
+
+      context "with a nullable model" do
+        let(:content) { ['@model MyModel', '@property name(nullable) [Name]  Name'] }
+
+        its(['name']) { is_expected.to eq('$ref' => '#/components/schemas/Name') }
+      end
+    end
+  end
+
   context 'with config.openapi_version set and Swagger.new' do
     subject { SwaggerYard::Swagger.new.to_h }
     before { SwaggerYard.config.openapi_version = '3.0.0' }