Remove EnumWithNil concern
What does this MR do?
With Rails version less than 6.1, we had the following behavior:
For the enum failure_reason: { unknown_failure: nil }
, when failure_reason
is nil
, we got:
object.failure_reason # => nil
while we expected
object.failure_reason # => "unknown_failure"
That's why EnumWithNil
has been implemented.
With Rails 6.1 we have the expected behaviour out-of-box, that's why we can remove EnumWithNil
.
The behaviour is tested implicitly in many places, we also have explicit tests: https://gitlab.com/gitlab-org/gitlab/blob/7b06f6bc577ab7b92af42f684ce81240d5707048/spec/models/commit_status_spec.rb#L686, so the coverage should be fine