Enable mapping to nil in enums

Enum in Rails 5 does not map nil values - IOW nil value remains nil,
even if there is a key with nil value in the enum definition.

This commit overrides the underlying Enum methods so nil value is
still mapped. This solution is far from being ideal: it uses dynamic
definition of methods which introduces more magic/confusion
into the codebase.

It would be better to get rid of the nil value in enums.

1 files changed, 2 insertions, 8 deletions

diff --git a/app/models/commit_status.rb b/app/models/commit_status.rb
index a7d05722287..97516079b66 100644
--- a/app/models/commit_status.rb
+++ b/app/models/commit_status.rb
@@ -3,6 +3,7 @@ class CommitStatus < ActiveRecord::Base
   include Importable
   include AfterCommitQueue
   include Presentable
+  include EnumWithNil
 
   self.table_name = 'ci_builds'
 
@@ -39,7 +40,7 @@ class CommitStatus < ActiveRecord::Base
   scope :retried_ordered, -> { retried.ordered.includes(project: :namespace) }
   scope :after_stage, -> (index) { where('stage_idx > ?', index) }
 
-  enum failure_reason: {
+  enum_with_nil failure_reason: {
     unknown_failure: nil,
     script_failure: 1,
     api_failure: 2,
@@ -190,11 +191,4 @@ class CommitStatus < ActiveRecord::Base
       v =~ /\d+/ ? v.to_i : v
     end
   end
-
-  # Rails 5.0 autogenerated question mark enum methods return wrong result if enum value is nil.
-  # They always return `false`.
-  # This method overwrites the autogenerated one to return correct result.
-  def unknown_failure?
-    Gitlab.rails5? ? failure_reason.nil? : super
-  end
 end