Delegate methods to default CI entry if undefined

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

@@ -14,6 +14,7 @@ module Gitlab
           def initialize(config)
             @config = config
             @nodes = {}
+
             @validator = self.class.validator.new(self)
             @validator.validate
           end
@@ -71,6 +72,10 @@ module Gitlab
             true
           end
+          def attributes
+            { key: @key, parent: @parent, description: @description }
+          end
+
           def self.default
           end

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

@@ -5,8 +5,9 @@ module Gitlab
         ##
         # This class represents an undefined entry node.
         #
-        # It takes original entry class as configuration and returns default
-        # value of original entry as self value.
+        # It takes original entry class as configuration and creates an object
+        # if original entry has a default value. If there is default value
+        # some methods are delegated to it.
         #
         #
         class Undefined < Entry
@@ -16,13 +17,35 @@ module Gitlab
             validates :config, type: Class
           end
+          def initialize(node)
+            super
+
+            unless node.default.nil?
+              @default = fabricate_default(node)
+            end
+          end
+
           def value
-            @config.default
+            @default.value if @default
+          end
+
+          def valid?
+            @default ? @default.valid? : true
+          end
+
+          def errors
+            @default ? @default.errors : []
           end
           def defined?
             false
           end
+
+          private
+
+          def fabricate_default(node)
+            Node::Factory.fabricate(node, node.default, attributes)
+          end
         end
       end
     end

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

@@ -9,11 +9,13 @@ describe Gitlab::Ci::Config::Node::Factory do
       it 'fabricates entry with attributes set' do
         fabricated = described_class
           .fabricate(entry_class, ['ls'],
-                     parent: factory, key: :test)
-        expect(fabricated.parent).to be factory
+                     parent: true, key: :test)
+        expect(fabricated.parent).to be true
         expect(fabricated.key).to eq :test
         expect(fabricated.value).to eq ['ls']
+        expect(fabricated.attributes)
+          .to eq(parent: true, key: :test, description: nil)
       end
     end

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

@@ -2,33 +2,62 @@ require 'spec_helper'
 describe Gitlab::Ci::Config::Node::Undefined do
   let(:undefined) { described_class.new(entry) }
-  let(:entry) { Class.new }
-  describe '#leaf?' do
-    it 'is leaf node' do
-      expect(undefined).to be_leaf
+  let(:entry) { spy('Entry') }
+  context 'when entry does not have a default value' do
+    before { allow(entry).to receive(:default).and_return(nil) }
+
+    describe '#leaf?' do
+      it 'is leaf node' do
+        expect(undefined).to be_leaf
+      end
     end
-  end
-  describe '#valid?' do
-    it 'is always valid' do
-      expect(undefined).to be_valid
+    describe '#valid?' do
+      it 'is always valid' do
+        expect(undefined).to be_valid
+      end
     end
-  end
-  describe '#errors' do
-    it 'is does not contain errors' do
-      expect(undefined.errors).to be_empty
+    describe '#errors' do
+      it 'is does not contain errors' do
+        expect(undefined.errors).to be_empty
+      end
+    end
+
+    describe '#value' do
+      it 'returns nil' do
+        expect(undefined.value).to eq nil
+      end
     end
   end
-  describe '#value' do
+  context 'when entry has a default value' do
     before do
       allow(entry).to receive(:default).and_return('some value')
+      allow(entry).to receive(:value).and_return('some value')
     end
-    it 'returns default value for entry' do
-      expect(undefined.value).to eq 'some value'
+    describe '#value' do
+      it 'returns default value for entry' do
+        expect(undefined.value).to eq 'some value'
+      end
+    end
+
+    describe '#errors' do
+      it 'delegates errors to default entry' do
+        expect(entry).to receive(:errors)
+
+        undefined.errors
+      end
+    end
+
+    describe '#valid?' do
+      it 'delegates valid? to default entry' do
+        expect(entry).to receive(:valid?)
+
+        undefined.valid?
+      end
     end
   end