[doc bug] StateNotConstructed not documented and hard to find the right incatation to import

[katfang]

Describe the bug

StateNotConstructed (and potentially other errors reboot throws) is either not in the docs, or the search doesn't turn them up, which makes it hard to know how to catch and handle the error.

Reboot server spat out

Exiting: LocPieceIndexGetAborted: rbt.v1alpha1.StateNotConstructed
    at Function.fromStatus (/Users/katfang/reboot/cheaoss/api/cheaoss/v1/piece_rbt.ts:2053:14)
    at LocPieceIndexWeakReference.__externalServiceCallGet (/Users/katfang/reboot/cheaoss/api/cheaoss/v1/piece_rbt.ts:3134:10)
    at async LocPieceIndexWeakReference.get (/Users/katfang/reboot/cheaoss/api/cheaoss/v1/piece_rbt.ts:3144:18)
    at async validateMoveWithBoard (/Users/katfang/reboot/cheaoss/backend/src/piece_servicer.ts:189:29) {
  error: StateNotConstructed { requiresConstructor: false },
  code: 10
}
unhandled error in runQueue PieceMovePieceAborted: rbt.v1alpha1.Unavailable: Socket closed
    at Function.fromStatus (/Users/katfang/reboot/cheaoss/api/cheaoss/v1/piece_rbt.ts:1781:14)
    at PieceWeakReference.__externalServiceCallMovePiece (/Users/katfang/reboot/cheaoss/api/cheaoss/v1/piece_rbt.ts:2587:10)
    at async PieceWeakReference.movePiece (/Users/katfang/reboot/cheaoss/api/cheaoss/v1/piece_rbt.ts:2597:18)
    at async GameServicer2.runQueue (/Users/katfang/reboot/cheaoss/backend/src/game_servicer.ts:322:7)
    at async Module.runWithContext (file:///Users/katfang/reboot/cheaoss/node_modules/@reboot-dev/reboot/index.js:138:12)
    at async GameServicer2._RunQueue (/Users/katfang/reboot/cheaoss/api/cheaoss/v1/game_rbt.ts:452:24) {
  error: Unavailable {},
  code: 14
}

Which is cool. The state not being constructed is not a problem, but I would like to catch it because that's a valid state to be in for me.

The following worked for me:

import { errors_pb } from "@reboot-dev/reboot-api";

// ...

      try {
        await LocPieceIndex.ref(refId).get(context);
      } catch (e) {
        if (e instanceof LocPieceIndex.GetAborted && e.error instanceof errors_pb.StateNotConstructed) {
          // handling non existence
        }
      }

Related to reboot-dev/mono#3943

To Reproduce
Steps to reproduce the behavior:

1. Attempt to call a reader method on a state id that doesn't exist.

Expected behavior

I expect the docs to tell me what errors can be thrown by Reboot itself (and ideally have examples for how I can import / catch them myself).

Impact
How severely does this bug impact your use of Reboot?

• It's not having any negative impact
• It's annoying
• It's a serious problem
• It makes it impossible for me to use Reboot

I only figured out the import via trial and error and some searching of StateNotConstructed in the docs (not found by search) and the repo (which is how I decided, maybe I attempting to import errors_pb instead of StateNotConstructed would work)

[rjhuijsman]

Seems like we should expand the docs section on Catching Expected Errors to include examples for the Reboot "built-in" errors in addition to self-declared errors.