Implement composed operations

[MathieuDutSik]

Motivation

Due to the control of the order of the operations by the signer of the blocks, the signer can choose the return of one operation to be the input of the next one.

Fixes #2037

Proposal

The idea is simply to introduce a

enum OperationInput {
  Composed,
  Direct(Vec<u8>),
}

with Direct being the previous mechanism. Since the BlockTracker has all the needed data, this works fine.

Where some problems occur is with the typed operations of Wasm smart contracts. We could introduce an OperationInput taking a typed input. But this introduces a number of type complications, and the method instead is to have two functions:

schedule_operation(A::Oeration)
schedule_composed_operation()

And so we get a relatively simple

Test Plan

The CI.
One test uses the Counter example which was modified to return a CounterOperation and so to be composed.

Release Plan

• Nothing to do / These changes follow the usual release cycle.

Links

None.

[ma2bd]

This is related to "scripts" or Sui's PTB. Great direction but we're going to need some solid design first.