L2 integration

[yrong]

Resolves: https://linear.app/snowfork/issue/SNO-1656

Context

This PR includes a POC demonstrating L2 integration using the Stargate composability call, based primarily on the following documentation:
https://docs.stargate.finance/developers/protocol-docs/composability

The dependent contract components have already been deployed on Sepolia (Ethereum and Optimism). We only need to configure the .env file in the contracts directory and run this command:

contracts git:(ron/l2-stargate) ✗ pnpm bridge-l2

• L1 transaction
  https://sepolia.etherscan.io/tx/0x8659d5360b65aaaa5d0f7d435a596da702db60f84ab227e49f5469909eecab73

• L2 transact
  https://testnet-explorer.optimism.io/tx/0x05fe693c2888a961f33797415cd1910070384410bd63ee11c3b810f7e7ff0e97

[yrong]

Though EURC on Base is not listed in the supported chain/token list (here), I checked the codebase (here) and it appears that support exists for Mainnet. I’ll double-check with the team to confirm.

[claravanstaden]

Hey @yrong! Looks very cool! Would we need to deploy these adapter, receiver, etc contracts on Mainnet? Would that be through Polkadot governance, or how do you imagine that would work?

[alistair-singh]

Though EURC on Base is not listed in the supported chain/token list (here), I checked the codebase (here) and it appears that support exists for Mainnet. I’ll double-check with the team to confirm.

I think we need to use the official Circle bridge for USDC/EUROC.

[alistair-singh]

Hey @yrong! Looks very cool! Would we need to deploy these adapter, receiver, etc contracts on Mainnet? Would that be through Polkadot governance, or how do you imagine that would work?

No governance at all, no upgrades, we just deploy the contracts. Then route xcm to the deployed contracts to complete the transfer. We build the xcm offchain so no governance required to route to these contracts. If we need to upgrade, we deploy a new set of contracts and then change the xcm to route to those contracts.

[alistair-singh]

I think whats missing from this, is a script which issues a transact from asset hub, that uses the composer to send ETH to base.

[yrong]

No governance at all, no upgrades, we just deploy the contracts. Then route xcm to the deployed contracts to complete the transfer. We build the xcm offchain so no governance required to route to these contracts. If we need to upgrade, we deploy a new set of contracts and then change the xcm to route to those contracts.

Yeah, I assume governance control won’t be required. For transactions from P to E, the user-controlled agent will communicate with the adaptor to perform certain L2 calls.

This is just a proof of concept to demonstrate the integration of a transfer and how to compose a message that is later executed on the destination side. For a pure token transfer from P to Ethereum L2, we might not even need the receiver contract.

For the reverse direction—from L2 back to Polkadot—the receiver on Ethereum L1 will forward the XCM and invoke the send function on the Gateway.

[yrong]

I think whats missing from this, is a script which issues a transact from asset hub, that uses the composer to send ETH to base.

We've done this before in the canonical bridge integration here: https://github.com/Snowfork/snowbridge/blob/main/smoketest/tests/v2/transact_p2e_l2.rs

I'll add another test for this integration as well.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.94%. Comparing base (2ab4c6f) to head (1b892f1).
⚠️ Report is 10 commits behind head on main.

Additional details and impacted files

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  Files          21       21           
  Lines         925      925           
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[yrong]

I think we need to use the official Circle bridge for USDC/EUROC.

I'd assume Stargate is a high-level ommichain protocol that leverages appropriate underlying messaging protocols such as LayerZero or Circle’s CCTP to execute the cross-chain token transfers.

Based on the code and comments here, it appears that this functionality is already supported.

[yrong]

Closed in favor of #1649