Rename CI config null node entry to undefined node

lib/gitlab/ci/config/node/configurable.rb

@@ -27,7 +27,7 @@ module Gitlab
 
           def create_node(key, factory)
             factory.with(value: @config[key], key: key)
-            factory.nullify! unless @config.has_key?(key)
+            factory.undefine! unless @config.has_key?(key)
             factory.create!
           end
 

lib/gitlab/ci/config/node/factory.rb

@@ -5,8 +5,6 @@ module Gitlab
         ##
         # Factory class responsible for fabricating node entry objects.
         #
-        # It uses Fluent Interface pattern to set all necessary attributes.
-        #
         class Factory
           class InvalidFactory < StandardError; end
 
@@ -20,8 +18,8 @@ module Gitlab
             self
           end
 
-          def nullify!
-            @entry_class = Node::Null
+          def undefine!
+            @entry_class = Node::Undefined
             self
           end
 

lib/gitlab/ci/config/node/undefined.rb

@@ -3,20 +3,15 @@ module Gitlab
     class Config
       module Node
         ##
-        # This class represents a configuration entry that is not being used
+        # This class represents a configuration entry that is not defined
         # in configuration file.
         #
-        # This implements Null Object pattern.
+        # This implements a Null Object pattern.
         #
-        class Null < Entry
-          def value
-            nil
-          end
-
-          def validate!
-            nil
-          end
-
+        # It can be initialized using a default value of entry that is not
+        # present in configuration.
+        #
+        class Undefined < Entry
           def method_missing(*)
             nil
           end

spec/lib/gitlab/ci/config/node/factory_spec.rb

@@ -45,14 +45,14 @@ describe Gitlab::Ci::Config::Node::Factory do
       end
     end
 
-    context 'when creating a null entry' do
+    context 'when creating undefined entry' do
       it 'creates a null entry' do
         entry = factory
           .with(value: nil)
-          .nullify!
+          .undefine!
           .create!
 
-        expect(entry).to be_an_instance_of Gitlab::Ci::Config::Node::Null
+        expect(entry).to be_an_instance_of Gitlab::Ci::Config::Node::Undefined
       end
     end
   end

spec/lib/gitlab/ci/config/node/undefined_spec.rb

@@ -1,7 +1,7 @@
 require 'spec_helper'
 
-describe Gitlab::Ci::Config::Node::Null do
-  let(:entry) { described_class.new(nil) }
+describe Gitlab::Ci::Config::Node::Undefined do
+  let(:entry) { described_class.new('some value') }
 
   describe '#leaf?' do
     it 'is leaf node' do
@@ -16,8 +16,8 @@ describe Gitlab::Ci::Config::Node::Null do
   end
 
   describe '#value' do
-    it 'returns nil' do
-      expect(entry.value).to be nil
+    it 'returns configured value' do
+      expect(entry.value).to eq 'some value'
     end
   end
 end