Handle warnings for param descriptions without a controller method

If we're generating swagger via
`SwaggerGenerator.json_schema_for_self_describing_class` we explicitly don't
have a `controller_method` being passed around so we can't use it for the
warnings. Introduce a test for type and builder to cover this scenario (first
spotted by a failing spec for `SwaggerGenerator`) and then change the
implementation to cope with it. Luckily,
`Apipie::Generator::Swagger::MethodDescription::Decorator` already had a
`ruby_name` implementation that handles being given `nil`, so we use that.

lib/apipie/generator/swagger/param_description/builder.rb

@@ -1,7 +1,7 @@
 class Apipie::Generator::Swagger::ParamDescription::Builder
   # @param [Apipie::ParamDescription] param_description
   # @param [TrueClass, FalseClass] in_schema
-  # @param [Apipie::MethodDescription] controller_method
+  # @param [Apipie::MethodDescription, nil] controller_method
   def initialize(param_description, in_schema:, controller_method:)
     @param_description = param_description
     @in_schema = in_schema
@@ -98,7 +98,7 @@ def required_from_path?
   def warn_optional_without_default_value(definition)
     if !required? && !definition.key?(:default)
       method_id =
-        if @param_description.is_a?(Apipie::ResponseDescriptionAdapter::PropDesc)
+        if @controller_method.present? && @param_description.is_a?(Apipie::ResponseDescriptionAdapter::PropDesc)
           @controller_method.method_name
         else
           Apipie::Generator::Swagger::MethodDescription::Decorator.new(@controller_method).ruby_name

lib/apipie/generator/swagger/param_description/type.rb

@@ -114,7 +114,11 @@ def validator
   def warn_hash_without_internal_typespec
     method_id =
       if @param_description.is_a?(Apipie::ResponseDescriptionAdapter::PropDesc)
-        @controller_method.method_name
+        if @controller_method.present?
+          @controller_method.method_name
+        else
+          Apipie::Generator::Swagger::MethodDescription::Decorator.new(nil).ruby_name
+        end
       else
         Apipie::Generator::Swagger::MethodDescription::Decorator.new(@param_description.method_description).ruby_name
       end

spec/lib/apipie/generator/swagger/param_description/builder_spec.rb

@@ -146,21 +146,33 @@
           ).to_stderr
         end
 
-        context 'and param is a prop desc with a delegated controller method' do
+        context 'and param is a prop desc' do
           let(:param_description) do
             Apipie.prop(:param, 'object', param_description_options, [])
           end
 
-          let(:method_desc) do
-            Apipie::Generator::Swagger::MethodDescription::Decorator.new(
-              Apipie::MethodDescription.new(:show, resource_desc, dsl_data)
-            )
+          context 'with a delegated controller method' do
+            let(:method_desc) do
+              Apipie::Generator::Swagger::MethodDescription::Decorator.new(
+                Apipie::MethodDescription.new(:show, resource_desc, dsl_data)
+              )
+            end
+
+            it 'warns' do
+              expect { subject }.to output(
+                /is optional but default value is not specified/
+              ).to_stderr
+            end
           end
 
-          it 'warns' do
-            expect { subject }.to output(
-              /is optional but default value is not specified/
-            ).to_stderr
+          context 'with a nil controller method' do
+            let(:method_desc) { nil }
+
+            it 'warns' do
+              expect { subject }.to output(
+                /is optional but default value is not specified/
+              ).to_stderr
+            end
           end
         end
       end

spec/lib/apipie/generator/swagger/param_description/type_spec.rb

@@ -180,19 +180,29 @@
         expect { subject }.to output(/is a generic Hash without an internal type specification/).to_stderr
       end
 
-      context 'and param is a prop desc with a delegated controller method' do
+      context 'and param is a prop desc' do
         let(:param_description) do
           Apipie.prop(param_description_name, 'object', {}, [])
         end
 
-        let(:controller_method) do
-          Apipie::Generator::Swagger::MethodDescription::Decorator.new(
-            method_desc
-          )
+        context 'with a delegated controller method' do
+          let(:controller_method) do
+            Apipie::Generator::Swagger::MethodDescription::Decorator.new(
+              method_desc
+            )
+          end
+
+          it 'outputs a hash without internal typespec warning' do
+            expect { subject }.to output(/is a generic Hash without an internal type specification/).to_stderr
+          end
         end
 
-        it 'outputs a hash without internal typespec warning' do
-          expect { subject }.to output(/is a generic Hash without an internal type specification/).to_stderr
+        context 'and controller method is nil' do
+          let(:controller_method) { nil }
+
+          it 'outputs a hash without internal typespec warning' do
+            expect { subject }.to output(/is a generic Hash without an internal type specification/).to_stderr
+          end
         end
       end
     end