make status startDate optional for Context

[gidsg]

Context

• RFC code: 0018

Explanation

https://github.com/openregister/registers-rfcs/blob/master/content/context-resource/index.md#status mandates a start-date but there is no logical value for this for an empty register, so in reality I think this field should be optional. See implementation in openregister/openregister-java#561 CC @MatMoore

[MatMoore]

In the data model I would express this by adding another case to "either active or retired" for the empty register case.

type Status
  = Pending
  | Active { startDate : Timestamp }
  | Retired { startDate : Timestamp
            , endDate : Timestamp
            , replacement : Maybe Url
            , reason : Text
            }

https://spec.openregister.org/v2/glossary/context#status

[arnau]

If the register is empty, the context resource has no meaning right? It means that there is no name, no hashing algorithm etc. Instead of making this value optional perhaps we should assess what does it mean for the API if we have a truly empty register. And what is a minimal viable register (as per the api).