Refactor only/except configuration policies

This commit refactors only/except policies so that these policies could
be self-contained. This also adds some changes to YAML configuration
library to provide more context to default entry value fabrication
process.

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

@@ -16,13 +16,6 @@ module Gitlab
                             dependencies before_script after_script variables
                             environment coverage retry parallel extends].freeze
 
-          DEFAULT_ONLY_POLICY = {
-            refs: %w(branches tags)
-          }.freeze
-
-          DEFAULT_EXCEPT_POLICY = {
-          }.freeze
-
           validations do
             validates :config, allowed_keys: ALLOWED_KEYS
             validates :config, presence: true
@@ -156,8 +149,8 @@ module Gitlab
               services: services_value,
               stage: stage_value,
               cache: cache_value,
-              only: DEFAULT_ONLY_POLICY.deep_merge(only_value.to_h),
-              except: DEFAULT_EXCEPT_POLICY.deep_merge(except_value.to_h),
+              only: only_value,
+              except: except_value.to_h,
               variables: variables_defined? ? variables_value : nil,
               environment: environment_defined? ? environment_value : nil,
               environment_name: environment_defined? ? environment_value[:name] : nil,

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

@@ -14,7 +14,7 @@ module Gitlab
             validates :config, key: true
           end
 
-          def self.default
+          def self.default(**)
             'default'
           end
         end

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

@@ -64,7 +64,14 @@ module Gitlab
             end
           end
 
-          def self.default
+          def value
+            self.class.default(key: @key).yield_self do |default|
+              default.to_h.deep_merge(@subject.value.to_h)
+            end
+          end
+
+          def self.default(**attributes)
+            { refs: %w(branches tags) } if attributes[:key] == :only
           end
         end
       end

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

@@ -82,9 +82,6 @@ module Gitlab
               'retry config'
             end
           end
-
-          def self.default
-          end
         end
       end
     end

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

@@ -14,7 +14,7 @@ module Gitlab
             validates :config, type: String
           end
 
-          def self.default
+          def self.default(**)
             'test'
           end
         end

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

@@ -14,7 +14,7 @@ module Gitlab
             validates :config, array_of_strings: true
           end
 
-          def self.default
+          def self.default(**)
             %w[build test deploy]
           end
         end

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

@@ -14,7 +14,7 @@ module Gitlab
             validates :config, variables: true
           end
 
-          def self.default
+          def self.default(**)
             {}
           end
 

lib/gitlab/config/entry/factory.rb

@@ -53,10 +53,10 @@ module Gitlab
           # If entry has a default value we fabricate concrete node
           # with default value.
           #
-          if @entry.default.nil?
+          if @entry.default(@attributes).nil?
             fabricate(Entry::Undefined)
           else
-            fabricate(@entry, @entry.default)
+            fabricate(@entry, @entry.default(@attributes))
           end
         end
 

lib/gitlab/config/entry/node.rb

@@ -85,7 +85,7 @@ module Gitlab
           "#<#{self.class.name} #{unspecified}{#{key}: #{val.inspect}}>"
         end
 
-        def self.default
+        def self.default(**)
         end
 
         def self.aspects

lib/gitlab/config/entry/simplifiable.rb

@@ -17,7 +17,7 @@ module Gitlab
 
           entry = self.class.entry_class(strategy)
 
-          super(entry.new(config, metadata))
+          super(@subject = entry.new(config, metadata))
         end
 
         def self.strategy(name, **opts)
@@ -37,6 +37,9 @@ module Gitlab
             self::UnknownStrategy
           end
         end
+
+        def self.default(**)
+        end
       end
     end
   end