Add CI config entry validator for allowed keys

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

@@ -18,23 +18,7 @@ module Gitlab
             description: 'Specify which paths should be cached across builds.'
 
           validations do
-            validate :keys
-
-            def unknown_keys
-              return [] unless config.is_a?(Hash)
-              config.keys - allowed_keys
-            end
-
-            def keys
-              if unknown_keys.any?
-                unknown_list = unknown_keys.join(', ')
-                errors.add(:config, "contains unknown keys: #{unknown_list}")
-              end
-            end
-          end
-
-          def allowed_keys
-            self.class.nodes.keys
+            validates :config, allowed_keys: true
           end
         end
       end

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

@@ -51,7 +51,7 @@ module Gitlab
               @config
             else
               defined = @nodes.select { |_key, value| value.defined? }
-              Hash[(defined).map { |key, node| [key, node.value] }]
+              Hash[defined.map { |key, node| [key, node.value] }]
             end
           end
 

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

@@ -21,6 +21,11 @@ module Gitlab
             'Validator'
           end
 
+          def unknown_keys
+            return [] unless config.is_a?(Hash)
+            config.keys - @node.class.nodes.keys
+          end
+
           private
 
           def location

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

@@ -3,6 +3,16 @@ module Gitlab
     class Config
       module Node
         module Validators
+          class AllowedKeysValidator < ActiveModel::EachValidator
+            def validate_each(record, attribute, value)
+              if record.unknown_keys.any?
+                unknown_list = record.unknown_keys.join(', ')
+                record.errors.add(:config,
+                                  "contains unknown keys: #{unknown_list}")
+              end
+            end
+          end
+
           class ArrayOfStringsValidator < ActiveModel::EachValidator
             include LegacyValidationHelpers