diff --git a/lib/gitlab/ci/config/node/factory.rb b/lib/gitlab/ci/config/node/factory.rb
index 707b052e6a8..5387f29ad59 100644
--- a/lib/gitlab/ci/config/node/factory.rb
+++ b/lib/gitlab/ci/config/node/factory.rb
@@ -37,8 +37,8 @@ module Gitlab
             # See issue #18775.
             #
             if @value.nil?
-              Node::Undefined.new(
-                fabricate_undefined
+              Node::Unspecified.new(
+                fabricate_unspecified
               )
             else
               fabricate(@node, @value)
@@ -47,13 +47,13 @@ module Gitlab
 
           private
 
-          def fabricate_undefined
+          def fabricate_unspecified
             ##
             # If node has a default value we fabricate concrete node
             # with default value.
             #
             if @node.default.nil?
-              fabricate(Node::Null)
+              fabricate(Node::Undefined)
             else
               fabricate(@node, @node.default)
             end
diff --git a/lib/gitlab/ci/config/node/null.rb b/lib/gitlab/ci/config/node/null.rb
deleted file mode 100644
index 88a5f53f13c..00000000000
--- a/lib/gitlab/ci/config/node/null.rb
+++ /dev/null
@@ -1,34 +0,0 @@
-module Gitlab
-  module Ci
-    class Config
-      module Node
-        ##
-        # This class represents an undefined node.
-        #
-        # Implements the Null Object pattern.
-        #
-        class Null < Entry
-          def value
-            nil
-          end
-
-          def valid?
-            true
-          end
-
-          def errors
-            []
-          end
-
-          def specified?
-            false
-          end
-
-          def relevant?
-            false
-          end
-        end
-      end
-    end
-  end
-end
diff --git a/lib/gitlab/ci/config/node/undefined.rb b/lib/gitlab/ci/config/node/undefined.rb
index 45fef8c3ae5..33e78023539 100644
--- a/lib/gitlab/ci/config/node/undefined.rb
+++ b/lib/gitlab/ci/config/node/undefined.rb
@@ -3,15 +3,34 @@ module Gitlab
     class Config
       module Node
         ##
-        # This class represents an unspecified entry node.
+        # This class represents an undefined node.
         #
-        # It decorates original entry adding method that indicates it is
-        # unspecified.
+        # Implements the Null Object pattern.
         #
-        class Undefined < SimpleDelegator
+        class Undefined < Entry
+          def initialize(*)
+            super(nil)
+          end
+
+          def value
+            nil
+          end
+
+          def valid?
+            true
+          end
+
+          def errors
+            []
+          end
+
           def specified?
             false
           end
+
+          def relevant?
+            false
+          end
         end
       end
     end
diff --git a/lib/gitlab/ci/config/node/unspecified.rb b/lib/gitlab/ci/config/node/unspecified.rb
new file mode 100644
index 00000000000..a7d1f6131b8
--- /dev/null
+++ b/lib/gitlab/ci/config/node/unspecified.rb
@@ -0,0 +1,19 @@
+module Gitlab
+  module Ci
+    class Config
+      module Node
+        ##
+        # This class represents an unspecified entry node.
+        #
+        # It decorates original entry adding method that indicates it is
+        # unspecified.
+        #
+        class Unspecified < SimpleDelegator
+          def specified?
+            false
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/lib/gitlab/ci/config/node/factory_spec.rb b/spec/lib/gitlab/ci/config/node/factory_spec.rb
index d26185ba585..a699089c563 100644
--- a/spec/lib/gitlab/ci/config/node/factory_spec.rb
+++ b/spec/lib/gitlab/ci/config/node/factory_spec.rb
@@ -65,7 +65,8 @@ describe Gitlab::Ci::Config::Node::Factory do
           .value(nil)
           .create!
 
-        expect(entry).to be_an_instance_of Gitlab::Ci::Config::Node::Undefined
+        expect(entry)
+          .to be_an_instance_of Gitlab::Ci::Config::Node::Unspecified
       end
     end
 
diff --git a/spec/lib/gitlab/ci/config/node/global_spec.rb b/spec/lib/gitlab/ci/config/node/global_spec.rb
index 2f87d270b36..dfe75bd09e5 100644
--- a/spec/lib/gitlab/ci/config/node/global_spec.rb
+++ b/spec/lib/gitlab/ci/config/node/global_spec.rb
@@ -156,9 +156,9 @@ describe Gitlab::Ci::Config::Node::Global do
           expect(global.descendants.count).to eq 8
         end
 
-        it 'contains undefined nodes' do
+        it 'contains unspecified nodes' do
           expect(global.descendants.first)
-            .to be_an_instance_of Gitlab::Ci::Config::Node::Undefined
+            .to be_an_instance_of Gitlab::Ci::Config::Node::Unspecified
         end
       end
 
diff --git a/spec/lib/gitlab/ci/config/node/null_spec.rb b/spec/lib/gitlab/ci/config/node/null_spec.rb
deleted file mode 100644
index 1ab5478dcfa..00000000000
--- a/spec/lib/gitlab/ci/config/node/null_spec.rb
+++ /dev/null
@@ -1,41 +0,0 @@
-require 'spec_helper'
-
-describe Gitlab::Ci::Config::Node::Null do
-  let(:null) { described_class.new(nil) }
-
-  describe '#leaf?' do
-    it 'is leaf node' do
-      expect(null).to be_leaf
-    end
-  end
-
-  describe '#valid?' do
-    it 'is always valid' do
-      expect(null).to be_valid
-    end
-  end
-
-  describe '#errors' do
-    it 'is does not contain errors' do
-      expect(null.errors).to be_empty
-    end
-  end
-
-  describe '#value' do
-    it 'returns nil' do
-      expect(null.value).to eq nil
-    end
-  end
-
-  describe '#relevant?' do
-    it 'is not relevant' do
-      expect(null.relevant?).to eq false
-    end
-  end
-
-  describe '#specified?' do
-    it 'is not defined' do
-      expect(null.specified?).to eq false
-    end
-  end
-end
diff --git a/spec/lib/gitlab/ci/config/node/undefined_spec.rb b/spec/lib/gitlab/ci/config/node/undefined_spec.rb
index 2d43e1c1a9d..6bde8602963 100644
--- a/spec/lib/gitlab/ci/config/node/undefined_spec.rb
+++ b/spec/lib/gitlab/ci/config/node/undefined_spec.rb
@@ -1,32 +1,41 @@
 require 'spec_helper'
 
 describe Gitlab::Ci::Config::Node::Undefined do
-  let(:undefined) { described_class.new(entry) }
-  let(:entry) { spy('Entry') }
+  let(:entry) { described_class.new }
+
+  describe '#leaf?' do
+    it 'is leaf node' do
+      expect(entry).to be_leaf
+    end
+  end
 
   describe '#valid?' do
-    it 'delegates method to entry' do
-      expect(undefined.valid).to eq entry
+    it 'is always valid' do
+      expect(entry).to be_valid
     end
   end
 
   describe '#errors' do
-    it 'delegates method to entry' do
-      expect(undefined.errors).to eq entry
+    it 'is does not contain errors' do
+      expect(entry.errors).to be_empty
     end
   end
 
   describe '#value' do
-    it 'delegates method to entry' do
-      expect(undefined.value).to eq entry
+    it 'returns nil' do
+      expect(entry.value).to eq nil
+    end
+  end
+
+  describe '#relevant?' do
+    it 'is not relevant' do
+      expect(entry.relevant?).to eq false
     end
   end
 
   describe '#specified?' do
-    it 'is always false' do
-      allow(entry).to receive(:specified?).and_return(true)
-
-      expect(undefined.specified?).to be false
+    it 'is not defined' do
+      expect(entry.specified?).to eq false
     end
   end
 end
diff --git a/spec/lib/gitlab/ci/config/node/unspecified_spec.rb b/spec/lib/gitlab/ci/config/node/unspecified_spec.rb
new file mode 100644
index 00000000000..ba3ceef24ce
--- /dev/null
+++ b/spec/lib/gitlab/ci/config/node/unspecified_spec.rb
@@ -0,0 +1,32 @@
+require 'spec_helper'
+
+describe Gitlab::Ci::Config::Node::Unspecified do
+  let(:unspecified) { described_class.new(entry) }
+  let(:entry) { spy('Entry') }
+
+  describe '#valid?' do
+    it 'delegates method to entry' do
+      expect(unspecified.valid?).to eq entry
+    end
+  end
+
+  describe '#errors' do
+    it 'delegates method to entry' do
+      expect(unspecified.errors).to eq entry
+    end
+  end
+
+  describe '#value' do
+    it 'delegates method to entry' do
+      expect(unspecified.value).to eq entry
+    end
+  end
+
+  describe '#specified?' do
+    it 'is always false' do
+      allow(entry).to receive(:specified?).and_return(true)
+
+      expect(unspecified.specified?).to be false
+    end
+  end
+end