[Rails5] Fix enum question mark methods

app/models/ci/pipeline.rb

@@ -530,6 +530,17 @@ module Ci
       @latest_builds_with_artifacts ||= builds.latest.with_artifacts_archive.to_a
     end
+    # Rails 5.0 autogenerated question mark enum methods return wrong result if enum value is nil.
+    # They always return `false`.
+    # These methods overwrite autogenerated ones to return correct results.
+    def unknown?
+      Gitlab.rails5? ? source.nil? : super
+    end
+
+    def unknown_source?
+      Gitlab.rails5? ? config_source.nil? : super
+    end
+
     private
     def ci_yaml_from_repo

app/models/commit_status.rb

@@ -189,4 +189,11 @@ 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