Double-check the consistency of STF execution status

[Kailai-Wang]

Context

It's common that an STF execution will call both parentchain extrinsic and sgx-runtime extrinsic. Ideally we need to make sure the state is synchronised between these: what if one extrinsic succeeds while the other fails? Then we have an inconsistent state.

We seek the long-term solution for it.

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@litentry/parachain

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🔐 This issue was closed because there has been no activity for 7 days since it became stale.

[Kailai-Wang]

Still relevant

[clangenb]

@coax1d is now working on implementing a generic parentchain event checker. integritee-network/worker#1272

In this PR, we will add a handling that is very similar to how we approach indirect calls. We will introduce a ParentchainEvent enum, on which we will implement a trait:

impl HandleParentchainEvent for ParentchainEvent {
   fn handle(self, executor: &IndirectExecutor) -> Result {
      match self {
            ExtrinsicSuccess(event) => event.handle(executor)
            ExtrinsicFailed(event) => event.handle(executor)
        }
   }
}

This is where I would handle failures of parentchain callbacks, essentially and roll-back, unreserve, unlock some sidechain stuff.

Note: some details are still being worked out on our end.

[kziemianek]

Practically this is not a case for us, because our callback logic is limited to depositing an event (except requesting a VC).
At worst the event might not be recorded on parachain. Does it mean we should rollback all the changes on sidechain ? I'm not sure.

Once we remove indirect calls the only output reported back to parachain would be VC generation.
On the sidechain side the VC generation is a stateless operation, thus no state incosistency can happen if parachain extrinsic fails.

I think there is nothing that needs to be solved now.