Use open poly variant to cover the FUTURE case

[rickyvetter]

Right now the SchemaAsset generated file uses a marker to signify that additional values could be added to the schema later so it is unsafe to exhaustively match. Could we instead use an open poly variant like so:

type t('a) = [> | `Case1 | `Case2 ] as 'a;`

[zth]

Sorry for missing this! You mean instead of including the FutureAddedValue case?

[rickyvetter]

Yeah - exactly. I am hoping that with the poly variant + some PR like rescript-lang/rescript#3801 but for poly variant would allow for a 0 runtime version of SchemaAsset. This would mean you'd have the very large Reason file, but JS byte size would be unaffected.

[zth]

@rickyvetter I'm intrigued! And I agree that would be the best thing to do. However, I'd like to wait until that actually lands in BuckleScript before I change anything. Do you have any insight on ongoing work for that particular feature?

At that point SchemaAssets.re could also be removed (although I plan on putting a few other things in there, so it might not after all), which would be nice.

[zth]

@rickyvetter likely starting work on this soon given that BS is approaching shipping that feature from what I can see. SchemaAssets.re is gone too now, for other reasons as well.

[zth]

This is implemented here #90 although in a slightly different shape. Waiting a stable BS release with the feature, and it'll be merged after that.

[zth]

Fixed in e36948f 🎉