Re: [BuildStream] Proposal: Artifact as a Proto

[Jim MacArthur <jim macarthur codethink co uk>]

On 14/01/2019 17:10, Raoul Hidalgo Charman via BuildStream-list wrote:
> As the ref just points to a digest, could it make sense to have it be 
> a digest
> of either an artifact proto or a directory proto? This would keep the reference
> service generic (and require no changes), and allow use of the new artifact proto.
> This means you would get an error if you used the wrong ref that was pointing to
> the other type, but you'd want an error to be raised if this happens anyway.
> There could be some issue with this I haven't thought of however.
I have no problem with the idea but the implementation might be a bit 
tricky - you need to know what type of object a ref is before decoding 
it; trying to decode something to the wrong protocol type will 
/probably/ throw an error, but I would rather not rely on that behaviour.