[SDK] Elastic Chain USDC (Circle) Bridge support in SDK

[pxrl]

Team or Project

Across Protocol

Select the SDK

JavaScript

ZK chain

Lens, any future Elastic chains supported by Across...

Environment

Mainnet

Issue Description

This issue relates to an incompatibility between the Matter Labs Elastic Chain USDC Bridge for Circle USDC (link) and the zkSync-ethers SDK. I have similarly not found any support in the corresponding viem package.

From what I can tell, it is impossible to finalize a USDC withdrawal via the Elastic Chain USDC bridge with the existing zksync-ethers SDK. The reason for this is that the Elastic Chain contracts diverge from the standard zkSync ERC20 shared bridge interface. Specifically, the SDK expects to query l2Brige.l1SharedBridge() to resolve a mainnet address. This function has been renamed to l2Bridge.l1USDCBridge() in the Elastic Chain USDC bridge, so the query to resolve l1SharedBridge() reverts.

The here for the commit where the interface incompatibility was introduced: matter-labs/usdc-bridge@29e76a6

I'm not aware of any alternative way of completing a USDC withdrawal with standard zkSync tooling (please correct me if I'm missing something). This is concretely an issue because the Elastic Chain USDC bridge has been deployed to (at least) Lens and is in production use, so guidance on how to complete a finalization with existing tooling would be appreciated.

Expected Behavior

It should be possible to finalize a withdrawal via the Elastic USDC bridge with standard zkSync tooling.

Code Example

No code example supplied.

Repo Link (Optional)

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[popzxc]

Hey. Thanks for reporting. Indeed, it makes sense to have support for USDC bridge in the SDK, although to avoid confusion it should be handled separately from the shared bridge.

I've created a task for that and we'll work on it soon: zksync-sdk/zksync-ethers#255

[pxrl]

Thanks @popzxc