chore(rln-relay): deprecate tree sync strategy

Background

With the changes to the rln-v2 contracts, it is now possible to fetch the merkleProofElements from the contract and use that to generate proofs instead.

Details

Add a proc to the contract definition in

nwaku/waku/waku_rln_relay/group_manager/on_chain/group_manager.nim

Lines 31 to 50 in 8d107b0

    
           contract(WakuRlnContract): 
        
             # this serves as an entrypoint into the rln membership set 
        
             proc register( 
        
               idCommitment: UInt256, userMessageLimit: UInt32 
        
             ) 
        
             # Initializes the implementation contract (only used in unit tests) 
        
             proc initialize(maxMessageLimit: UInt256) 
        
             # this event is raised when a new member is registered 
        
             proc MemberRegistered( 
        
               rateCommitment: UInt256, index: Uint32 
        
             ) {.event.} 
        
             # this function denotes existence of a given user 
        
             proc memberExists(idCommitment: Uint256): UInt256 {.view.} 
        
             # this constant describes the next index of a new member 
        
             proc commitmentIndex(): UInt256 {.view.} 
        
             # this constant describes the block number this contract was deployed on 
        
             proc deployedBlockNumber(): UInt256 {.view.} 
        
             # this constant describes max message limit of rln contract 
        
             proc MAX_MESSAGE_LIMIT(): UInt256 {.view.}

like so -

  # this function returns the merkleProof for a given index
  proc merkleProofElements(index: Uint32): seq[Uint256] {.view.}

and fetch it every time an event is emitted by the contract. Use this to generate proofs instead.

Acceptance criteria

A list of tasks that need to be done for the issue to be considered resolved.

Cache the root of the tree every time an event is emitted by the contract
Use the new api in zerokit to generate proofs by passing in the serialized witness
Cache the merkleProof every time an event is emitted by the contract
Override the GroupManager.generateProof in the OnchainGroupManager by using the custom witness we will pass in

This issue is blocked at the moment due to our nim-web3 dependency being out of date. The version we use does not support returning a sequence of elements from the smart contract.

After bumping to the latest version of nim-web3, transaction signing seems to not work as expected, and hence we're blocked

@seemenkina I know with this issue being blocked your focus has been elsewhere, but do you know if there's an update on the nim-web3 limitation?

@jm-clius as I see yesterday they started using a newer version of nim in the dependencies - I suspect it will now be possible to continue with this task

@seemenkina, thanks for the feedback. My understanding from nwaku is that the dependencies in nwaku will be updated within the next few days. :) cc @NagyZoltanPeter

	contract(WakuRlnContract):
	# this serves as an entrypoint into the rln membership set
	proc register(
	idCommitment: UInt256, userMessageLimit: UInt32
	)
	# Initializes the implementation contract (only used in unit tests)
	proc initialize(maxMessageLimit: UInt256)
	# this event is raised when a new member is registered
	proc MemberRegistered(
	rateCommitment: UInt256, index: Uint32
	) {.event.}

	# this function denotes existence of a given user
	proc memberExists(idCommitment: Uint256): UInt256 {.view.}
	# this constant describes the next index of a new member
	proc commitmentIndex(): UInt256 {.view.}
	# this constant describes the block number this contract was deployed on
	proc deployedBlockNumber(): UInt256 {.view.}
	# this constant describes max message limit of rln contract
	proc MAX_MESSAGE_LIMIT(): UInt256 {.view.}